Building Systems, Materials, & Assemblies Flashcards
General comfort range
69-80 degrees with a stretch of 60-85 degrees
IMC andIBS requirements for heating systems
require any space for human occupancy to be provided with an active or passive space heating system capable of maintaining a min indoor temp of 68 degrees at a point of 3’ aff on the design heating day
Effective temp
a derived value that combines the effects of air temp, humidity, and air movement
Dry bulb temp
measured with standard thermometer
Wet bulb temp
measured with sling psychrometer, a thermometer with a moist cloth around the bulb; hygrometer systems have been taking the place of sling psychrometers
Relative humidity
the ratio of the percentage of moisture in the air to the maximum amount of moisture that the air can hold at a given temp without condensing; comfortable ranges between 30% and 65%; tolerable ranges between 20% and 70%
Windchill effect
a tolerable cold temp becomes unbearable when there is wind
Air movement speeds
50 ft/min - 200 ft/min is usually not annoying
Emissivity
a measure of an object’s ability to absorb and then radiate heat
Emittance
the ratio of the radiation given by an object or material to that emitted by a black body at the same temperature
Mean radiant temp
a weighted average of the various surface temps in a room and the angle of exposure of the occupant to these surfaces, as well as of any sunlight present
Operative temp
an average of the air temp of a space and the MRT of the space
Clo
the unit to quantify the effects of clothing; one clo is equal to the thermal insulation given by the typical business suit; 0.15 clo per pound of clothing
IMC requirements for ventilation
requires every occupied space to be provided with either natural or mechanical ventilation
Natural ventilation size
area to be opened to the outdoors equal to at least 4% of the floor area being ventilated; if through another room, the area must be equal to at least 8% of the interior space
Mechanical ventilation rate
rate of supply air brought into the room or space must be approx equal to the rate or return air, or exhaust air, carried out of it; positive pressure may be needed
Comfort carts
-Show the relationships among temp, humidity, and other comfort factors
-humidity limits of 30% to 65% are preferred to be used
Psychrometric chart
-A graphical representation of the complex interactions between heat, air, and moisture
-used to calculate how much heat and moisture needs to be added or removed by an HVAC system for comfort
Enthalpy
the total amount of both sensible and latent heat in the air-moisture mixture
Enthalpy line
used to determine the total amount of heat that must be either removed or added
Heat loss calculations
Helps determine the size of the heating system for the building
Thermal conductivity, k
the rate at which heat passes through 1 SF of a 1” thickness of the material when the temp differential is 1 degree
Conductance, C
Same as Thermal conductivity, but the thickness is other than 1”
Resistance, R
the number of hours needed for 1 Btu to pay through a material of a given thickness when the temp differential is 1 degree
R = k/C
A heat loss calculation; material values given in standard reference texts and ASHRAE Handbook of Fundamentals
Overall coefficient of heat transmission, U
the value used to calculate heat loss when a building assembly uses more than one material
U= 1/sum of R values
q=UA(temp difference)
total heat loss, q, when the entire area is made of one material
Calculating total heat loss of different assemblies
all assemblies and materials must first have their heat loss calculated and then added together
deltaT or temp difference
determined by subtracting the outdoor design temp from the desired indoor temp in the winter, usually 70 deg; outdoor design temp in ASHRAE or set by municipality
Vapor barrier is placed on which side of insulation
placed on the warm side of insulation
Thermal gradient
shows variance in temp through a cross section of a construction assembly to help locate the dew-point temp
Heat loss through infiltration calculation
qv = V(1.08)deltaT
V, volumetric flow rate of air infiltration
Design equivalent temperature difference (DETD)
takes into account the air temp differences, effects of the sun, thermal mass storage effects of materials, colors of finishes exposed to the sun, and daily temp range; values published in ASHRAE tables
design cooling load factor (DCLF)
takes into account type of glazing, type of interior shading, and outdoor design temp; multiplied by the area of glazing to determine the heat gain through glazing
Sensible heat
heat that causes a change in temp of a substance but not a change of state
Latent heat
heat that causes a change of state of a substance
Heat gain through infiltration calculation
Multiply the total area by an infiltration factor
If mechanical ventilation, calculation
the volume of air being introduced to the building is multiplied by the amount of heat that must be extracted both to cool and to remove excess humidity
Energy sources
Natural gas (propane)
Oil
Electricity
Steam
Heat pumps
Natural energy sources
Natural gas
-Most efficient; clean burning; and relatively low cost
-may not be readily available, especially in rural locations
-propane: a type of gas roar can be used in areas where natural gas is not available; delivered in pressurized tanks
Oil
-Usually widely available depending on region
-cost and availability depend on world and local market conditions
-stored in or near the building
-equipment for burning requires more maintenance
Electricity
-Easy and inexpensive to install
-simple to operate
-easy to control
-flexible in zoning
-cost for use is high compared to other fuels; sometimes more charged for peak use
-on-site photovoltaics can reduce the reliance on utility supplied electricity
-ideal for radiant heating
Steam
-Not basic
-used most often on campuses and in urban locations; available from a central plant; by-product of electricity
-not usually used for direct heating; piped into building and used to heat water and drive absorption type water chillers for ac
Heat pumps
-A device that reverses the natural flow of heat travel from warm to cool; absorbs heat from a cooler location and transfer to a warmer one using principles of refrigeration
-can heat in the winter and cool in the summer
-heating efficiency decreases as outdoor temp decreses
-more effective in milder temperate climates
-solar energy system or electrical resistance heating may be used supplementarily
Natural energy sources
-Solar, PV, geothermal, wind, and tidal
-solar readily available and cost efficient
-PV harder to justify cost
Degree days
rough measure of how much heating is needed for human comfort in a particular location over the course of a year; difference between base line indoor temp of 65 degrees and average outside temp for the day
Degree days are used to determine
how much fuel is needed; daily values for the year are added to get the total number of degree days for the year
Typical fuel efficiencies
-natural gas - 70-80%
-propane - 70-90%
-no.2 oil - 65-85%
-anthracite coal - 65-75%
-electricity - 95-100%
Most common fuel to heat converters
Furnaces and boilers
How furnaces work
furnace burns fuel inside a combustion chamber, air circulated around chamber by fan, cool air returning to chamber circulated and is heated for distribution; exhausts gases
Forced air furnace, upflow
the return air is supplied at the bottom of the unit and the heated air is delivered to the bonnet above the furnace where it is distributed through ductwork
Forced air furnace, downflow
opposite operation; used in cases where ductwork is located in a basement or crawl space and the furnace is located on the first floor
Forced air furnace, horizontal
designed to be used in areas where headroom is limited, like crawl spaces
How boilers work
uses fuel to create hot water or steam; fuel is gas, electricity, oil, or steam; tubes containing water to be heated are within the combustion chamber
If primary fuel source is electricity or steam
an exhaust flue is not needed
How compressive refrigeration works
Based on the transfer of heat during the liquefaction and evaporation of refrigerant; as refrigerant as a gas is compressed it liquefies and releases latent heat as it changes state; liquid expands and vaporizes back to gas, absorbs latent heat
Fundamental component of compressive refrigeration system, compressor
receives the refrigerant as a gas and compresses it, turning it into a liquid
Fundamental component of compressive refrigeration system, condenser
the liquid flows into here and its latent heat is released; usually located on outside of building
Fundamental component of compressive refrigeration system, evaporator
refrigerant enters here and draws heat from its surroundings (air or water) and expands, becoming gas again; leaves evaporator and reenters compressor to begin again
Absorption refrigeration
-most often done with steam, also with high temp water produces by solar collectors
-less efficient than compressive refrigerants
-most often used when waste heat is available for energy input to the generator part of the system
How Evaporative cooling works
Water dropped over pads or fin tubes through which outdoor air or water is circulated; water evaporated and heat is drawn from the air of water circulating; cooled air then distributed
only works in hot-arid climates ; can be more cost effective in these climates and simpler construction and operation
ton of refrigerant or ton of cooling
a unit to describe the capacity of a refrigeration system
HVAC System, Direct Expansion Systems
-Also known as incremental unit
-simplest type of HVAC
-self-contained; passes non ducted air over an evaporator which cools the air; air discharged into room
-ventilation comes from outside
-through-wall, roof mounted, or packaged
-⅓ to 2 ton capacity for individual rooms
-capacity over 2 ton serve several rooms in one zone
-add a heating oil and DX can heat too
HVAC System, All Air Systems
-Cools or heats using only condition air
-heat transferred via supply and return ducts
-most basic is constant volume single duct; single duct common in residential and small commercial; air heated or cooled in central furnace of air conditioner and distributed via ductwork at a constant volume; 1 central thermostat; simple but cannot be zoned
variable air volume systems VAV
heated or cooled as needed in central plan and distributed at a constant temp through a single duct; each zone has a thermostat controlling a sampler that varies volume of conditioned air entering; dampers at return allow variable amount of fresh air to be introduced for ventilation and cooling when outdoor temps mean the space doesn’t;t need to be mechanically conditioned; limited in a ability to compensate for extremes; very efficient
high-velocity dual-duct system
2 parallel ducts run to each space; one with hot air and one with cool air; both stream joined in mixing box in proportion to temp; thermostat control pneumatic valves in mixing box; zones can essentially be used; ducts can be smaller to save space; inefficient because both hot and cool are supplied at all times; larger fans, more energy; noisy; high initial cost for ducts
reheat (constant volume) system
return air and outdoor air mixed; cools and dehumidifies mixture; distributed at constant volume at low temp; air reheated as needed based on the cooling load at to neat the space; reheating with heated water, or sometimes with electricity;if reheating equipment is near space its terminal reheat system; if located in ductwork of an entire zone, unit is called a zone reheat system; thermostats control valves in the water supply line and regulate temp; sometime economizer cycle is used to allow outdoor air to be used for cooling when temps are low; humidity and temp can be carefully controlled and low supply temp equates to smaller ducts and lower fan horsepower; uses more energy
multizone system
supplies air to a central mixing unit where separate heating and cooling coils produce SPE rate hot and cold airstreams; mixed with dampers controlled by zone thermostats; offer same advantage as dual-duct systems in that simultaneous cooling and heating of different zones can be accommodated; disadvantage is duct space is larger when zones are added; usually only used for medium-sized buildings or where central mixing unit can be located on each floor
HVAC System, All Water Systems
-Uses a fan coil unit in each conditioned space; fan coils connected to one or two water circuits; ventilation provided with opening through the wall at the location of the fan coil unit, from interior zone air heating or by simple infiltration
-a supply pipe and return pipe
-efficient way to transfer heat
-easily controlled; thermostat in each room regulated how much water flows through the coils
-humidity control not possible at central unit
HVAC System, Air Water Systems
-Relies on a central air system to provide humidity control and ventilation air to conditioned spaces
-majority of heating and cooling is provided by fan coil units located in each space
-often used where return air cannot be recirculated because of the potential for contamination (hospitals and labs); 100% outside air is supplied and return air is exhausted to exterior
-induction system used to supply air throughout the building under high pressure and velocity to each induction unit, where velocity and noise are attenuated before the air passes over the coils and is heated or cooled as needed; water supply system delivers heated or chilled water to the coils through either a 2 or 4 pipe system; thermostatic control is provided to each unit or group of units by regulating the amount and temp of water flowing through coils
HVAC System, Electric System
-Common method uses a grid of wires in the ceiling to provide radiant heating
electric baseboard radiators
-provides a uniform, clean, inconspicuous form of heating that can be controlled with a separate thermostat in each room
-Ductwork and piping not needed
-not usually economical except where electricity is inexpensive
-mostly used for supplemental heating in localized radiant panels or where water or air systems may need a boost in temp
Selection of Systems, profile of the building
flexibility for tenants, multiple uses or variations in heating and cooling loads
Selection of Systems, building scale
central vs individual units
Selection of Systems, control needs
sleeping rooms or units and tenants need thermostatic control
Selection of Systems, fuels available
most often which fuel system is most readily and economically available
Selection of Systems, climatic zone
wide swings in temp, humidity
Selection of Systems, flexibility
change internally by tenants and added onto in future
Selection of Systems, integration with building systems
structure and height; coordination with disciplines
Selection of Systems, economics
initial costs, long term maintenance, cost of operating the system
Selection of Systems, HVAC systems for building types
-Direct expansion: residential - single family
-constant volume single duct: auditoriums/theaters, churches, hospitals, hotels/motels, laboratories, residential-single family, shopping centers
-variable air volume: auditoriums/theaters, churches, commercial-small, labs, libraries, office buildings, shopping centers
-dual duct, high velocity: hospitals, labs
-constant volume, terminal reheat: hospitals, labs
-multizone: auditoriums/theaters, churches, commercial-small, hospitals, libraries, office buildings
-all-water system: commercial-small, residential-single family
-all-water induction: hospitals, office buildings
-closed loop heat pumps: apartments, hotels/motels
-fan coil: apartments, hospitals, hotels/motels, office buildings, schools
-electric: commercial-small, residential-single family
Exhaust systems includes
Systems designed to handle hazardous and nonhazardous exhaust and systems needed for specific equipment operations and those intended to exhaust away from sources of contamination
Energy Conservation, Mechanical System Components
Reasonable to include energy-efficient mechanical systems in an overall strategy for energy conservation and sustainability
Energy Conservation, Economizer Cycle
-Uses outdoor air when it’s cooled enough to mix with recirculated indoor air
-reduces energy needed for refrigeration and useful when outdoor temp is ~60 degrees; as temps drop less outdoor air is used to reduce the need to heat it
-a mechanical substitute for a window
Energy Conservation, Dual Condenser Cooling
-Refrigeration equipment uses 2 condensers instead of one
-when heat is needed, the heat recovery condenser is used to send waste heat to fan coil units or other devices
-when heat is not needed, heat rejection condenser sends heat to the cooling towers
-multiple chiller sizes can be used instead of one large one to make use of the most efficient size
Energy Conservation, Gas Fired Absorption Cooling
-Do not rely on electricity and ozone-depleting refrigerants; usually powered by natural gas, a more economical fuel; if steam or high temp water is available it can be used
-not as efficient as electrically driven chillers; high initial costs reject more heat to cooling towers
-may be more efficient for larger buildings where electricity costs are high and low cost heat sources for steam or industrial processed are available
-equipment may also provide hot water for heating
Energy Conservation, Solar Powered Absorption Cooling
-Absorption chillers more efficient and sustainable if powered by hot water from solar collectors
-may be less expensive than running compressive chillers with electricity, even though efficiency of solar collectors is low; efficiency can be increased by using parabolic concentrating solar collectors to provide water at a higher temp
Energy Conservation, Solar Powered Desiccant Cooling
-Desiccants to dehumidify and cool air by means of evaporative cooling; a material, either liquid or solid, that absorbs water
-air passed over desiccant mounted to a wheel rotating in the airstream; it is cooled and dehumidified; thermal energy dries out desiccant to be used again
Energy Conservation, Direct Contact Water Heaters
-Passes hot gasses directly through water to heat it; natural gas burned to provide flue gases that transfer heat to the water; heat exchanger in combustion chamber reclaims heat lost
-water is considered safe for human consumption
-up to 99% efficient if inlet water is below 59 degrees
-lower emissions of carbon monoxide and nitrous oxide
-high-cost; best used where hot water is on continuous demand (food processing, laundries, and industrial purposes)
Energy Conservation, Recuperative Gas Boilers
-Also called fuel economizer or boiler economizer
-recovers the heat in the flue gases that would normally be discharged
-Designed to cool the flue gas enough to achieve condensation so both latent and sensible heat are recovered
-reclaimed heat used to preheat the cold water entering the boiler or to preheat combustion air
-efficiency at about 95%
-Some systems reduce carbon monoxide and nitrous oxide emissions
-flue gases cool when emitted, plastic vents can be used so easy installation
Energy Conservation, Displacement Ventilation
-An air distribution system in which supply air is dispensed at floor level and rises to return air grilles in the ceiling as it warms
-because at floor level does not have to be cooled as much, more energy efficient
-typically uses high percentage of outside air
-can be used with personal control and flexible underfloor wiring
-access and space in floor; only in new construction where floor to floor height can accommodate 12” or more for ductwork
-only for space next to an exterior wall to a depth of 16’
Energy Conservation, Water Loop Heat Pumps
-Uses a series of heat pumps for different zones; all connected to the same piping system of circulating water; water loop maintain between 60-90 degrees
-Some zones are in cooling mode and simultaneously some zones are in heating mode; no additional energy has to be added when they’re balanced
-automatic valves at the cooling tower and boiler direct water as needed
-very efficient when simultaneous need for heat and cooling in different parts of the building
Energy Conservation, Thermal Energy Storage
-Uses water, ice, or rock beds to store excess heat or coolness for use at a later time
-makes it possible to manage energy needs over climatic temp swings through the day or week and allows use of less expensive off-peak energy costs to cool
Heat Transfer, Energy Recovery Ventilators (or air-to-air heat exchangers)
-reclaim waste energy from the exhaust air stream and use it to condition incoming fresh air
-most efficient in very cold, hot, or humid climates where temp differential between indoor and outdoor is high; building with continuous occupancy such as hotels and hospitals
-3 conditions to meet:
—fresh air intake must be as far away from exhaust outlet as possible to avoid sucking exhaust in
—exhaust air that contains excessive moisture, grease, or other contaminants should be separated from the heat exchanger air
—in cold winter conditions, a defroster in the device may be needed to prevent the condensate in the exhaust air from freezing
I-MC allows up to 10% of recirculated air to allow the used of energy recovery ventilators
-prohibited in hazardous exhaust systems; dust, stock, and refuse systems that convey explosive or flammable vapors; smoke control systems; commercial kitchen exhaust systems; clothes dryer exhaust systems
3 common devices to facilitate air-to-air heat exchange
—flat-plate heat recovery units: 2 ducts separated by a thin wall, one for exhaust one for inlet; can only exchange sensible heat; no humidity control
—energy transfer wheels, or enthalpy heat exchangers: transfer heat between 2 airstreams through a heat exchanger wheel; air passes through small holes in wheel that are impregnated with lithium chloride or something that absorbs moisture and transfers it to the other airstream
—heat pipe: a self-contained device that transfers sensible heat energy from hot exhaust air to cool outdoor air; the hot air passes over the heat pipe and vaporizes a refrigerant in the pipe that then moves to a section of the pipe exposed to cool incoming air; the refrigerant condenses and released heat to the incoming air, warming it; incoming and outgoing pipes must be adjacent
Heat Transfer, Water-to Water Heat Exchangers (or runaround coils)
-use water or other liquid transfer medium to exchange heat
-incoming and exhaust airstreams do not have to be adjacent
-hot exhaust air passed over coils of heat transfer fluid; fluid pumped into coils that cool incoming air passes over; winter
-cooled indoor air exhausted is used to reduce the temp of hot incoming air; summer
-common in large buildings
-eliminate the possibility incoming air can be contaminated with exhaust air
-efficiency 50-70%
Heat Transfer, Extract-Air Windows
-Uses a double-panel insulated glass unit over which another pane of glass is placed on the inside of the building
-air drawn up between interior pane and the main window unit and extracted into return air system
-warms glass in winter and cools in summer; eliminates the need for separate perimeter heating system
Heat Transfer, Ground-Coupled Heat Exchangers
-Heat or cool outside air by circulating it though pipes buried in the ground
-suitable for low-rise buildings
-long runs of pipes for efficient operation
-The energy saved by using the system must outweigh the energy needed to run the fans
-Ground-source heat pump: an alternate that takes advantage of geothermal energy
Heat Transfer, Chilled Beams
-A ceiling mounted unit that uses water to provide cooling and heating
-2 types
-multiservice chilled beam system: combines an active chilled beam system with other building services such as lighting, sprinklers, data cabling, and building management system sensors
-high initial cost
-offer significant energy savings over radiation do all-air and all-water HVAC; lower maintenance; compact; quieter
passive chilled beam system
relies on natural convection; provides only cooling; usually above a suspended ceiling; air cooled by contact with piping attached to fins and sinks back down; seerate ventilation ducts required but they can be smaller; the water temp must be a little higher than the rooms dew point to avoid condensation, therefor the central chillers can be smaller; humidity of ventilation must be done through separate equipment
Active chilled beam system
integrated with ventilation system and can heat and cool; fresh air drawn in and heated or cooled and then forced out; can handle temp control and humidity at same time
Heat Transfer, Variable Refrigerant Floor (VRF) Systems
-uses a single compressor and condenser unit located outdoors, connected to multiple evaporators located in different zones
-refrigerant supplied at each zone instead of the chilled and heated water used in typical all-water systems; each evaporator individually controlled; the amount of refrigerant supplied to each zone varies
-power consumption is reduced
-can also use heat pump tech or heat recovery to allow simultaneous heating and cooling in different zones; reduces life-cycle energy costs
-Ideal for offices, hotels, schools, multifamily residential, and Andy building with varying loads and zones; Reno work because small size of piping and compressor and evaporators; not for large open volumes
-quicker installation; quiet; flexibility in location of equipment, reduced piping, central control, monitor energy use as part of building management system
Heat Transfer, Building Automation Systems (BAS)
-a computer-based system used to monitor and control building systems
-systems controlled will vary depending on the complexity of the building and the needs of the owner; typically include HVAC, energy management, lighting, life safety, and security; may also include vertical transportation, communications, material handling, and landscape irrigation
-reduces energy costs, allows for monitoring of large complex buildings, reduces the number of personnel needed to supervise a large building, improves occupant comfort, provides detailed documentation of the performance of the subsystems
-BAS informs building systems manager if problem arises
Heat Transfer, BAS, Energy Management System (EMS)
detects environmental conditions both inside and outside the building, monitors the status of all equipment (including temp, humidity, and flow rates), and optimizes the control of the equipment (including start and stop times and operation adjustments)
Ampere
amp; A; the unit flow of electrons in a conductor equal to 6.241 x 10^18 electrons passing a given section in 1 sec
Energy
the product of power and time, also called work
Impedance
the resistance in an alternating current (AC) circuit, measured in ohms
Ohm
the unit of resistance in an electrical conduit
Power factor
the phase difference between the voltage and current in an alternating current circuit
Reactance
part of the electrical resistance in an alternating current circuit, caused by inductance and capacitance
Volt
v; unit of electromotive force or potential difference. 1 V is the amount of force or potential difference that will cause a current of 1 A to flow through a conductor whose resistance is 1 ohm
Watt
W; unit of electrical power
Basic electrical circuit
consists of a conductor, the actual flow of electrons (current), an electric potential difference to cause the electrons to move (voltage), and some type of resistance to the flow of electrons; the circuit can be interrupted with a switch
Ohm’s law for DC circuits
the current in a circuit is directly proportional to the voltage and inversely proportional to the resistance: I=V/R
Power
the rate at which work is done or the rate at which energy is used; in electric circuits expressed as watts
DC Power
Watt is the amount of power in a circuit when V is one volt and I is one amp; P=VI
PIE
power (P) equals current (I) times electromotive force (E)(another term for voltage)
AC voltage
represented as sine wave; amplitude of waves is the voltage and distance between peaks is one cycle; frequency measured in hertz or cycles per second; frequency is 60Hz in America
the power factor can be a significant factor in calculating power in an AC circuit
Circuits with only restrictive loads
have a power factor of 1
Ohm’s law for AC circuits
I=V/Z
calculation for power in AC circuits
P=VI(pf)
Units of how energy is measured
in watt-hours (W-hr) but more commonly measured in thousands of watt-hours or kilowatt-hours (kW-hr)
To calculate energy used in a system
Multiply power by times E=Pt
2 basic types of electric circuits
—series circuit: loads (zig zag lines in diagrams) are placed in the circuit one after another; the current, I, remains constant but the voltage potential changes or drops across each load; not used in building construction
—parallel circuit: loads are placed between the same 2 points; voltage remains the same but the current is different across each load; adding up the individual currents results in a total current that is applied to the circuit as a whole
Conductor
Basic material of an electrical system
most common conductors are copper and aluminum; aluminum has to be larger but is lighter and lower installation cost in larger sizes; aluminum limited to primary circuits with careful installation
Cable
single insulated conductor, no.6 AWG or larger, or several conductors assembled into a single unit
Wire
8 American Wire Gauge and smaller
Ampacity
current carrying capacity of a conductor; depends on conductor size, the type of insulation around it, and the surrounding temp
Conduit
supports and protects wiring, serves as a system ground, and protects surrounding construction from fire if the wire overheats or shorts; usually needed in commercial or a large residential for individual conductors
How many 90 degree bends are allowed between pull boxes?
No more than 4
Underfloor raceway, underfloor ducts
steel raceways cast into concrete floor at regular intervals (4, 5, or 6 ft); feeder ducts run perpendicular and carry power and signal wiring from the main electrical closet to each distribution duct; preset inserts placed along distribution ducts at close intervals and tapped where an outlet connection is needed
Underfloor raceway, cellular metal floors
part of the structural floor; cells are closer together; alternating cells used for power, telephone, and signal cabling; cellular floors also have reset locations that can be easily tapped to install electrical outlets, telephone jacks, and computer outlets
AC, alternating current
most common for of electrical energy in buildings
DC, direct current
used for some types of elevator motors and low-voltage applications such as signal systems, controls, and similar equipment
Providing Electrical service
provided to property line; owner installed and pays for wiring, metering, transformers, and distribution beyond that point
overhead service at smaller projects connects a service cable to a weatherhead mounted at least 12’ above the ground
sometimes for larger commercial buildings its more cost effective to pay for a higher voltage for the transformer to step down rather than pay a higher charge for lower voltages
120/240 V , single phase, three-wire system
most common for residences and very small buildings
120/208 V , three phase, four-wire system
most common in larger buildings; allows for variety of electrical loads
277/480 V, three phase, four-wire system
also used in larger buildings; same as 120/208 V except voltage is higher; system can use smaller feeders, smaller conduit, and smaller switchgear; 277 V fluorescent lighting used; step-down transformers used where 120 V service is needed
2400/4160 V, three phase, four-wire system
used in very large commercial buildings and factories
Transformer
-Used to change alternating current voltages either up or down
-owner supplied the transformer unless its a residence or small building, in which case the utility company usually supplies step-down transformers to serve a small group of houses
-Rated on their capacity in units of kilovolt-empires (kVa); described by their type, phase, voltage, method of cooling, insulation, and noise level
-for cooling transformers are wither dry, oil-filled, or silicone filled
-transformers on outside wall and vented to outside
Watt-hour meter
most commons; registers the use of power over time in kilowatt-hours
Load factor
the ratio of the power used to the max power demand; low load factor is inefficient
Load control
a method used to avoid peak electricity use
Max interval demand
the average amount of energy used in a a certain time period such as 15 min or 30 min
most utility companies make charges based on this
Switchgear
-central electrical distribution center
-needed by large buildings
-switchgear consists of switches, circuit breakers, and cables or bus ducts that distribute power to other parts of the building; transformer and metering often included; equipment usually housed in separate room which may be required to have fire rated walls and doors and panic hardware
-power coming through meter and transformer split into separate circuits, each with a master switch and circuit breaker to protect the circuit from overload or short circuits; switchgear distributes power to substations
Power supplied is not always steady and regulated
individual power surge and voltage variation problems can be solved with specific pieces of equipment such as voltage regulators, surge suppressors, and filters
Power conditioning units can be used where?
in larger computer rooms or for sensitive electronic equipment
Harmonic current
voltage or current at a frequency that is a multiple of the fundamental frequency; a problem for many buildings containing computers and other electronic equipment; produced by electrical loads that are nonlinear which includes almost any load other than simple resistive loads such as incandescent lights, heaters, and motors; problems can include overheating of the neutral conductor wiring, nuisance tripping of circuit breakers, overheated transformers, and telephone interference ; solved by over sizing the neutral conductor and adding passive harmonic filters or active line conditioning that introduces the line voltage and adds and equal but out-of-phase voltage to cancel the harmonics
Secondary Distribution
-Power from main switch board distributed to individual panel boards where further split into individual branch circuits used for power, lighting, motors, and other needs
-involves the lower voltages of 120 V, 240 V, and 277 V
Each circuit is protected with what?
circuit breakers in panel board; rated for the amperage the circuit is expected to carry ranging from 15 A and 20 A for general lighting and power circuits to 100 A or more for main disconnect switches or large loads
Protection for electric circuits, grounding
provides a path for a fault; ground wire and neutral wire grounded at the building service entrance to either a grounding electrode buried in the earth or in the foundation or to a buried cold water pipe; all new construction grounded with a separate wire in addition to the hot and neutral wiring of each circuit
Protection for electric circuits, ground fault circuit interrupters (GFCIs)
devices that can detect current leaks; if detected the device disconnects the power to the circuit or appliance; can be part of a circuit breaker or installed as an outlet; required in bathrooms, garages, accessory buildings at or below grade, crawl spaces, unfinished basements, countertop receptacles in kitchens, laundry and utility rooms, and boathouses as well as outdoors and within 6’ of the outside edge of a wet bar (all in dwellings)
Protection for electric circuits, arc-fault circuit interrupter (AFCIs)
helps protect against the effects pf arc faults by recognizing characteristics that are unique to arching and by de-energizing the circuit when an arc fault is detected; sometimes required in bedroom branch circuits that serve both receptacles and lighting; NEC requires them on 15 A and 20 A branch circuits that supply outlets in family rooms, dining rooms, living rooms, libraries, dens, sunrooms, recreation rooms, closets, hallways, and similar rooms
Hardwired
electrical devices that are connected to the building circuits in junction boxes rather than plugged in
Split-wired receptacle
one outlet is always energized and the other is controlled from a wall switch
Receptacle mounting heights
typically mounted 12-18” aff; min 15” aff for forward and side reach accessibility
Most residential convenience outlet circuits are what amperage?
15 A but at least 2 20 A appliance circuits must be provided for kitchen, pantry, breakfast room, and dining room
Outlets in kitchens
not more than 24” from any point on the wall above the countertop; outlets GFCI
Two-way switch
when one switch controls a device; switch needs 2 conductors to function
Low-voltage switching
individual switches are operated on a 24 V circuit and control relays that provide the 120 V switching; more costly to install; the device can be controlled from several positions, a central control station can be set up to monitor the entire system and override control, control devices such as timers and energy management systems can be wired to override local control, and are a less expensive option when a large installation needs flexibility of control
Power line carrier system (PLC)
uses the power lines to carry control signals; no additional wiring needed
Switching required by model and energy conservation codes
individual switches rather than one switch to control all devices
Dimmers are not effective at reducing power consumption
Instead, use automatic lighting controls like a time-of-day controller
Lighting typical in commercial settings
fluorescent lights are on 277 V circuits and incandescent lights are on 120 V circuits
Emergency power supply
Required for electrical systems that relate or the safety of occupants or community needs; exit lighting, alarms, elevators, telephones, fire pumps, and medical equipment if it should have life threatening implications
What water needs to be treated for
-PH level: a measure of the relative acidity or alkalinity of water, based on scale or 0-14 with pH of 7 as neutral; below 7 is acidic, above is alkaline; rain is naturally slightly acidic
-hard water caused by calcium and magnesium salts; can cause clogged pipes and corrosion of boilers and inhibits cleaning action of detergent
-turbidity caused by suspended material in the water such as silt, clay, and organic material; not hazardous but unpleasant and treated by filtration
-color problems and odor problems cause by organic matter, inorganic salts, or dissolved gases; odor corrected with filtration through activated charcoal; color corrected though fine filtration or chlorination
-biological contamination caused by bacteria, viruses, protozoa
Pretreatment
Removes suspended matter and large particles
sedimentation uses gravity and still water and clean water on top is piped out to a secondary filtration system; can happen with or without coagulation and flocculation
Coagulation
the process of getting particles to stick together by adding alum or other chemicals
Flocculation
the step after coagulation, the mix of water and alum sent to still water, where the particles and alum form a loosely aggregated mass called floc and are heavy enough for sedimentation to take place
Filtration, slow sand filtration
allows water to seep through a bed of fine sand about 3-4’ deep; biological slime forms on sand and traps small particles and degrades organic matter; don’t require coagulation and flocculation
excellent to filter out Giardia and particulates but now for water with high turbidity
Filtration, direct
passes water under pressure through a filter medium; includes coagulation and filtration and maybe flocculation
good for elimination Giardia and most viruses
Filtration, packaged
same as direct except all elements are placed in a single unit for direct hookup to water supply
Filtration, diatomaceous earth
uses a thin layer of dia earth ⅛ - ⅕” thick placed on a septum or filter element
good for removing cysts, algae, and asbestos but not as good at removing bacteria and turbidity
Filtration, membrane
forces water at high pressure through a thin membrane that removed particles 0.2 something and larger as well as Giardia, other bacteria, some viruses, and microorganisms
Filtration, cartridge
uses self-contained units places along the water supply line to filter out particles 0.2 and larger; cartridges must be replaces when fouled but useful at faucets
Demineralization
Removed dissolved solids and the chemicals that cause hard water
Demineralization, ion exchange
used in water softeners to treat hard water and remove cadmium, chromium silver, radium, and other chemicals. Hard water piped into softener which contains zeolite; calcium or magnesium ions exchanged for sodium ions; softened must be recharged periodically; water must be pretreated
Demineralization, reverse osmosis (RO)
removes contaminants by using semipermeable membrane that allows only water to pass through and not dissolved ions; useful for removing inorganic chemicals, bacteria, and suspended particles; unit cleaned by forcing clear water through membrane which leaves contaminants in brine that must be disposed of
Demineralization, electrodialysis
places charged membranes at the inflow stream of water to attract counter ions can remove barium, cadmium, selenium, fluoride, and nitrates; expensive to buy and operate and require high water pressure and a source of direct current power
Disinfection
Destroys microorganisms that can cause humans diseases
Disinfection, chlorination
most common and kills organizations by introducing chlorine into the water stream
Disinfection, chloramine
similar to chlorination but a weaker disinfectant; add ammonia to water that contains chlorine; a secondary disinfectant to prevent bacterial regrowth in a distribution system
Disinfection, ozonation
disinfects water through the use of ozone; used as a primary disinfectant and requires secondary disinfectant for water supplies; used for treating cooling tower water to prevent Legionella pneumophila, scale, and algae
Disinfection, ultraviolet light (UV)
destroys a cell’s ability to reproduce and effective against bacteria and viruses; not effective against Giardia Or Cryptosporidium and not useful for water that contains high levels of turbidity, suspended solids, or soluble organic matter; used with a secondary disinfectant to prevent regrowth
Disinfection, nanofiltration
uses filter membranes capable or trapping particles as small as one nanometer; removes bacteria, viruses, pesticides, and organic materials; water must be forced through at high pressure
Distillation
water is boiled and then vapors are condensed to remove solids, bacteria, salts, and other material; used to treat seawater often
Aeration or oxidation
used to improve the taste and color of water; aids in the removal of iron and manganese by oxidizing them so they can be more easily removed by filtration; simple process through which as much of the water as possible is exposed to air through the use of sprays, fountains, or waterfalls; drinking water aerated in an enclosed space or tank
Depth of a well
ranges from less than 25’ (shallow well) to several hundred feet; talk to locals to take a guess at depth
Yield of a well
is the number of gallons per minute it provides; 5-10 GMP is the min required for private residence; if too low a large storage tank may need to be provided
Suction pumps
only for water tables less than 25’
Deep-well pumps
for 25-100’
Turbine pumps
used for high capacity systems with deep wells
Submersible pumps
one of the most common for moderate to deep walls serving private residences or small buildings
Pressure tanks
used to maintain a constant water pressure for use in the building to compensate for brief peak use demand that exceeds the capacity of the pump
Water mains should be adjacent to the property, but if not
the owner is often required to extend the line to the site at their own cost
All solar heating systems have what
some type of solar collector, a storage tank, associated piping to move fluids, and a backup heater
Direct system or open-loop system
water used in the building is the same after that is heated in the collar collectors; simple and highly efficient but subject to freezing; must use a draining system
indirect system or closed-loop system
a separate fluid for collection heat is transferred to the domestic hot water; easier to protect from freezing because the fluid can contain antifreeze and can operate at lower pressure; but needs a heat exchanger so loses efficiency; can be circulated actively or passively
Solar heating system, batch systems
heats water directly in a black-painted tank inside a glazed box; passive system; simple; subject to freezing and night heat loss
Solar heating systems, thermosiphon system
relies on the natural movement of heated water to circulate the water in a passive, open-loop system; simple but storage tanks must be located above the collectors and piping must be kept simple to minimize pipe friction; a variation uses a closed-loop system with antifreeze to combat freezing
Solar heating system, closed-loop active system
one of most common systems for residential and commercial; separate, nonfreezing fluid is circulated by pumps through eh collar collectors and into a heat exchanger where the domestic hot water is heater; differential controller senses when temp of the collector is lower than the stored water and turns the pumps off; flexible and provides control but suffers from some loss in efficiency because of need for heat exchanger
Solar heating system, drain-down system
a direct, active system that solves the problem of freezing by automatically draining the water form the collector when the outside temps are near freezing; water water so best fro climates with mild winters where draining is not frequent
Solar heating system, drain-back systems
indirect active system that uses water as the heat collector fluid; heated water pumped to a heat exchanger where a coil of domestic hot water is heated; when controller sense temp too low it turns off the pump and the collector water drains back into the solar storage tank
Solar heating system, phase change system
hot water systems can also take advantage of phase change materials as the collector fluid; phase change materials store large amounts of latent and sensible heat
Long span structures
Generally over 60’ in length
One-way systems
linear members span in one direction and resist loads primarily by beam action, or bending; primary members bridge the long distance and a series of secondary members span between the primary one
Two-way systems
distribute loads to supports in both directions and involve complex, 3D methods of revisiting loads
Steel girders
-Rolled steel members; used if loads are not excessive; 44” depth is largest available size to span 72’; if more moment-carrying capacity needed cover plates can be welded to top and bottom of flanges
-if longer spans are required they have to be made from individual components: most common is plate girder which is sheet steel as webs and steel bar or angles as flanges; efficient
-plate girders used as roof beams can be angled toward the middle
-plate girders usually 8’ deep or more; can be used to transfer load of one column to 2 others; stiffeners are likely required
Rigid frames
-The vertical and horizontal members and joints resist loads primarily by flexure and in which moments are transferred from beams to columns; looks like the outline of a house, 2 vertical lines connected by a gable type pitch
-if fixed connections between columns and foundation and between the 2 halves it is an indeterminate structure
-if pinned connections at the same points as above it is determinate and does not develop secondary stresses caused by temp differences
-used for industrial facilities, warehouses, manufacturing plants, and other instances where a simple rectangular open space is required
-primarily made of steel but sometimes glulam
Trusses
-Straight members that form a number of triangles, with the connections arranged so that the stresses in the members are either in compression or tension.
-efficient to span long distances cuz rely on compression and tension, not bending, and high strength to weight ratio
-relatively light, mech equip friendly, can be partially prefab, efficient use of material, probably made as deep and large to span any distance
-number of connections increases fab and erection time
-spaced 10-40’ OC with purlins spanning between and bearing on panel points (where web members intersect the top chord); decking spans between purlins
Open web steel joists and joist girders
-Prefab truss members using hot-rolled or cold-formed steel members
-3 major groups: K-series (spans up to 60’), LH-series (direct support of floors and roof decks) , and DLH-series (direct support of roof decks) (both these are long span)
-LH-series (long span joists)
—18-48” depth, span up to 96’
-DLH series (deep long span joists)
—52-72” depth, span up to 144’; depths increase in 2-4” increments
-underslung or square ends
-made with camber, the rise in the beam to compensate for deflection
-very flexible; can bear on steel beams, masonry walls, concrete walls, and joists girders
-lightweight, goes up quick and easy
-Joist girders serve as primary structure that support evenly spaced open-web joists; available in 20-120” depth and span 100’; made with steel angle sections
Vierendeel trusses
-Composed of a series of rigid rectangular frames; no triangle members so not a true truss; members must resist bending and tension and compression
-used when diagonal members are not wanted and sometimes occupies entire story height
-must be designed with bigger members and joints must resist moments; therefore often have triangular brackets
Glued-laminated beams
Much larger span than normal wood members but seldom exceeds 60’ long span
Prestressed Concrete
-Has a member that has had an internal stress applied before it is subjected to service loads; stressed by stressing high-strength steel strands in a form into which concrete is formed; when concrete cures the external stress is removed and is transferred to the concrete; helps also reduce cracking and deflection and can span longer spans with smaller sections that with reinforced cast-in-place construction
-3 most common long span sections:
—Single tees: 4, 6, or 8’ w with 8-12” thick web and 1-4’ d with spans up to 120’
—double tees: 8-10’ w with 2” flange thickness and 8-32” d; spans 60-80’; 2” thick concrete topping to cover the joints; function both as structure and decking; inexpensive to produce; quick erection; used as either horizontal or vertical members; space between can be used for mech and elec runs
—AASHTO: generally limited to highway bridges but similar rectangular beams can be precast to span long distances with lengths up to 120’
Post-tensioned concrete
-Concrete member cast with hollow sleeves embedded in it to allow a chamber for high-strength steel cables called tendons; after concrete cured tension is applied to the tendons by hydraulic jacks
-can be used in floor slabs, beams, or other sections to increase the load-carrying capacity of the member
Arches
-Depends on compression to resist loads
-internal forces makes the arch want to spread, the tendency to spread is called thrust and is inversely proportional to the rise or height of the arch: as rise increases thrust decreases
-typical range is 50-240’ for wood, 50-500’ for steel, 40-320’ for concrete
-typical depth-to-span ratios are 1:40 for wood and up to 1:100 for steel
-can be fixed or hinged; if hinged at supports it can moved slightly under loads caused by temp, soil settlement, and winds without developing high bending stresses
-arches primary structure with secondary members spanning in between to support the roofing system
Design and selection for consideration for one-way systems
-function
-cost and economy
-shipping
—Max length is 60’ for truck shipment and 80’ for railroad shipment
—max height is 14’ for truck shipment
—site limitations may also be a problem
-acoustics
—Barrel vaults, domes, and polygonal shapes can increase the noise level or produce undesirable echoes
-assembly and erection
-fire protection
—Cost and difficulty of installing fire protection covering may offset the initial cost or an otherwise efficient material
—steel vulnerable to high temps
—IBC allows A and E occupancies to be without fire protection is the roof is more than 25’ above the floor
Large span structures, two-way systems
-Distribute loads in 2 or more directions and consist of members that are all primary
-structurally more efficient than one way systems
-Most efficient if the shape is a square so loads are equally distributed
-if rectangular more load is carried in the short dimension than the long dimension, if the proportion is 2:1 nearly all load is carried in the short dimension
-offers redundancy so the failure of one connection will not cause the others to fail too
-more complicated to design and build
-nearly all of them can only be used for roof structures due to their shape, space frames are exceptions; applies only to long span systems
Space frames
-3D structural system that transfers loads through a network of members attached to each other at nodal connection points
-Very efficient because of the large number of members and they resist loads primarily in compression or tension
-redundancy is featured
-have a top chord grid and a bottom chord grid connected with diagonal bracing; the 2 grids can be identical and run in the same direction or run in different directions while still forming a regular pattern; grids can be square or triangular
-simplest form is a 2-way truss system; trusses span 2 direction and are interconnected to form a grid on square openings; diagonal members are vertical and in the plane of each truss
-more common version is the offset grid; top and bottom grids consist of identical squares but the bottom one is offset by ½ grid; connected with skewed diagonal members
-most economical depth-to-module ratio is about 0.707; the larger the size the fewer connections the less it costs
-cantilevers of 15-30% of the span are possible and desirable since less chord material is used
Domes
-One of the most efficient structural systems because the shape helps resist loads placed on it primarily through compression and tension (and shear is it’s a thin-shell structure )
-3 basic variations: frame dome, geodesic dome, and thin-shell dome
-The compression and expansion of the meridians of the domes is held in check by the hoops of the dome
Geodesic domes
-Like space frames formed in the shape of a phere
-grid is based on circle arcs and is composed of spherical polyhedrons formed of equilateral triangles
-extremely strong and still and lightweight; enclose the greatest volume with the least surface area
-can easily span 400’ or more
Thin-shell structures
-A class of form-resistant structures whose strength is a result of their ability to support loads through compression, tension, and shear in the plane of the shell because off their basic shape
-the other form resistant structure is membranes which can only support loads through tension
-most common single curved shell is the barrel vault; end frames can be added to transfer the load to the ground
-lamella roof: a structure formed by 2 intersecting grids of parallel skewed arches covering a rectangular area; very efficient
-doubly curved shells: synclastic shells (those with curves on the same side of the surface) and anticlastic shells (those with tha main curves on the opposite sides of the structure) (hyperbolic paraboloid)
-very rigid and efficient; every part of it is resisting compression, tension, and shear
Membrane structures
-Can only resist loads in tension
-must be anchored between elements that can be places in compression like the poles of a tent
-very efficient in material use; they move and change shape in response to varying loads and flutter in the wind; can restless the membrane with enticlastic shapes to counteract these problems
Air-supported structures
-Another form of the membrane structure; also called pneumatic roof
-Still only supports loads through tension but the membrane is held in place by air pressure rather than cables and compression members
-inflate the membrane
Folded plates
-Thin slabs bent to increase the load-carrying capacity
-stronger than simple horizontal flat plates because instead of having a structural depth just the thickness of the slab, the structural depth is as deep as the fold of the plate; the span is mess, only the distance from one edge of the slab to the other
-can span up to 100’ in longitudinal direction and 25-35’ between outer folds of each plate assembly
-most commonly built of concrete but can also be plywood, steel or aluminum
-Short stiffening slab usually places at both edge boundaries to compensate for the additional stress
Suspension structures
-Only resist loads by tension; the material is utilized to the fullest unit stress capability
-the amount of tensile force is inversely related to the sag of the cable; the greater the sag the less the tension on the cable; as sag increases the tensile force and amount of able cross-sectional area required decreases but the length of the cable increases
-ideal proportion is that the sage is ½ the span so that cable is at a 45 deg angle
-optimal sag for parabolic cable is 3/10 of the span
-Optimal sag for catenary curve is ⅓ of the span
-unstable in the wind and with concentrated loads or other types of changing loads
Design and selection considerations for two-way systems
-function
-cost and economy
-shipping
—less of a problem because most assembly is done on site
-acoustics
-assembly and erection
—higher erection costs due to more labor components
Preliminary sizing of structural systems
-most common method is calculate the depth-to-span ratio
-ratios for floor systems can be reduced by 15% when calculating the structural systems for roofs
Transmittance or coefficient of transmittance
the ratio of the total transmitted light to the total incident light
—clear glass has 85% transmittance
—frosted glass has 70-85% transmittance
Translucent
a material that allows the transmittance of light but not of a clear image
reflectance or reflectance coefficient
the ratio of the total reflected light to the total incident light
Candlepower
the unit of luminous intensity approximately equal to the horizontal light output from an ordinary wax candle. Called the candela
Illuminance
the density of luminous flux incident on a surface, expressed in lumens per unit area; one lumen uniformly incident on 1 SF of area produces an illuminance of 1 foot-candle (fc)
Lumen
(lm) the unit of luminous flux equal in a unit solid angle of 1 steradian from a uniform point source of 1 candlepower; on a unit sphere (1’ radius) an area of 1 SF will subtend an angle of 1 steradian; area is 4pi, a source of 1 candlepower produces 12.57 lm
Luminance
the luminous flux per unit of projected (apparent) area and unit solid angle leaving a surface, either reflected or transmitted; the SI unit is the candela over square meter (cd/m2) also called the nit; in US the unit is the footlambert (fL) where 1 fL is 1/pi candlepower per SF; it takes into account the reflectance and transmittance properties of materials and the directions in which they are viewed
Luminous intensity
the solid angular flux density in a given direction measured in candlepower or candelas
Light levels
target age range is 25-65; if 50% are older than 65 the illuminance is doubled; if 50% are younger than 25 the illuminance is halved
visual comfort probability (VCP)
used to evaluate the problem of direct glare; the percentage of normal observers who may be expected to experience visual comfort in a particular environment with a particular lighting situation
Critical zone for direct glare
in the area above 45deg angle from the light source
Reflected glare
occurs when a light source is reflected from a viewed surface into the eye
Veiling reflection
if the glare interferes with the viewing task
Contrast
-The difference in illumination level between a given point and nearby points
-brightness ratios should usually be limited to 3:1 between the task and adjacent surroundings; 5:1 between the task and more remote darker surfaces; 1:10 between the task and more remote lighter surfaces
Uniformity
Affects a person’s perception of a space as being comfortable and pleasant; complete uniformity is usually not desirable except for detail oriented tasks
4 primary types of light sources besides daylight
-incandescent lamps
-fluorescent lamps
-high-intensity discharge (HID) lamps
-light-emitting diodes
Efficacy
the ratio of luminous flux emitted to the total power input to the source and is measured in lumens per watt; measures energy efficiency of a light source
Incandescent lamps
-inexpensive, compact, easy to dim, repeatedly started, warm color rendition; light can be controlled with reflectors and lenses
-low efficacy, short lamp life, high heat output; undesirable for large energy efficient installations
tungsten halogen lamp
pretty much the same make up but there is some halogen I mixed with the inert gas; longer bulb life, low lumen depreciation over the life of the bulb, more uniform color; bulb is made from quartz and is smaller than standard; can explode so usually double walled or shielded
reflector lamps (R lamps) and parabolic aluminized reflector lamps (PAR lamps)
contain reflective coating built into the lamp; increases efficacy and allows more precise beam control; available in flood (wide) and narrow (spot) beam dispersal patterns; PAR made with heavier glass and outdoor suitable
Elliptical reflector lamps (ER lamps)
improved version of R lamps; more efficient throw of light by focusing the light beam at a point slightly in front of the lamp before it spreads out; the spread is slightly smaller than R lamp; used for down lights with deep baffles or small openings
low-voltage miniature reflector lamps (MR lamps)
small tungsten-halogen lamps that are available in a variety of wattages and beam spreads; consistent high output and 2000-3000 hr lamp life; usually whiter
Fluorescent Lamps
-Contain a mixture of an inert gas and low-pressure mercury vapor; mercury arc is formed to create ultraviolet light which strikes the phosphor-coated bulb to fluoresce and produce visible light
-high efficacy, low initial cost, long life, available in many color temps, dimmable though expensive
-larger than incandescent, more difficult to control precisely, more suitable for general illumination
-compact fluorescent lamp (CFL) are smaller and brighter; Dow lights with reflector designs can replace incandescent downlights
-fluorescent lamps are produced in tubular shapes
Fluorescent, reheat lamp
don’t carry a current unless in operation and will not begin luminescing until the cathode has reached operating temp; supplanted by rapid-start types
Fluorescent, rapid-start lamp
maintain a constant low current in the cathode that allows them to start within about 2 seconds
Fluorescent, instant-start lamp
maintain a constant voltage high enough to start the arc in the tube directly without preheating the cathode
High-Intensity Discharge Lamps
-Include mercury vapor, metal halide, and high- and low-pressure sodium
-HID lights need time to restart after shut-off; must cool first then warm up
-3 types of outer bulbs:
—clear bulbs: used when optical control is required
—phosphor-coated bulbs: used for better color renditions
—diffuse bulbs: specified in recessed downlights installed in low ceilings
mercury vapor lamp
electric arc passed through high-pressure mercury vapor which produces both ultraviolet light and visible light in mostly blue-green; phosphors can be applied to inside of lamp to produce more yellow or red light; moderately high efficacy
metal halide lamp
similar to mercury but a combo of metal halides have been added to the arc tube; provide best combo of features for many purposes: color rendering index between 60-90, high efficacy, relatively long life; color temp shifts over its life; have outer bulb
ceramic metal halide lamp (CMH lamp)
uses ceramic arc tube instead of quartz tube so lamp can burn at higher temp, improved color rendition and light control; better efficacy than old version; higher initial cost, difficult to dim, need a ballast; useful in high ceilings and retail for point source control and color rendition
high pressure sodium lamp (HPS lamp)
electric arc passed through hot sodium vapor; arc tube made of special ceramic material; high efficacy makes them one of the most efficient lamps available; extremely long life; very yellow light but color correction is available
low pressure sodium lamps (LPS lamp)
even higher efficacy but a deep yellow color; best for street lighting or where color rendition is not important
Light Emitting Diodes (LEDs)
-A semiconductor device that uses solid-state electronics to create light; basic unit is the LED package combined with other packaged into a lamp and them into a LED luminaire; solid state lighting that includes organic light-emitting diodes and polymer light-emitting diodes
-brightness, long life, lack of heat production, low power consumption; 50000-100000 hours; can be directly controlled by a digital interface; many colors
-low efficacy, high cost
Articulation index
a measure of speech intelligibility calculated from the number of words read from a selected list that is understood by an audience; low index (less than 0.14) is desirable for speech privacy, high index (above 0.6) is desirable for good communication
Attenuation
the reduction of sound
impact insulation class (IIC)
a single-number rating of a floor-ceiling assembly’s impact sound transmission performance at various frequencies
Noise criteria (NC)
a set of single-number ratings of acceptable background noise corresponding to a set of curves specifying sound pressure levels across octave bands. Can be used to specify continuous background noise, achieve sound isolation, and evaluate existing noise situations
Noise isolation class (NIC)
a single-number rating of noise reduction
noise reduction (NR)
the arithmetic difference in decibels between the intensity levels of 2 rooms separated by a barrier of a given transmission loss; dependent on the transmission loss of the barrier, the area of the barrier, and the absorption of the surfaces of the receiving room
noise reduction coefficient (NRC)
the average sound absorption coefficient to the nearest 0.05, measured at the 4 one-third octave band center frequencies of 250 Hz, 500 Hz, 1000 Hz, and 2000 Hz
sound absorption coefficient
the ratio of the sound intensity absorbed by a material to the total intensity reaching the material; 1.00 is the max possible value of the coefficient
sound transmission class (STC)
an average of a barrier’s ability to reduce sound over several frequency bands; the higher the STC rating the better the barrier’s ability to control sound transmission
transmission loss (TL)
the difference in decibels between the sound power incident on a barrier in a source room and the sound power radiated into a receiving room on the opposite side of the barrier
change in intensity level (dB) to change in apparent loudness
-1_almost imperceptible
-3_just perceptible
-5_clearly noticeable
-6_change when distance to source in a free field is doubled or halved
-10_twice or half as loud
-18_very much louder or quieter
-20_four times or one-fourth as loud
Addition of decibels of uncorrelated sound
-Decibels are logarithmic and cannot be added directly
-guidelines - where difference between the 2 values is_ - add this value to the higher value:
—0 or 1 dB - 3 dB
—2 or 3 dB - 2 dB
—4 to 8 dB - 1 dB
—9 or more dB - 0 dB
-for 3 or more sources add the first 2 then add the result to the third number, and so on
-for the addition of an arbitrary number, n, of sources of identical value: ILtotal = ILsource + 10log(n)
Human sensitivity to sound
Normal ear can hear 20-20,000 Hz; more sensitive to frequencies in 3000-4000 Hz range
Transmission loss
the difference (in decibels) between the sound power incident on a barrier in a source room ad the sound power radiated into a receiving room on the opposite side of the barrier
Noise reduction calculation
calculated using:
-NR = TL + 10log(A/S)
-A is in metric sabins and S is in m2; 1 metric Sabin = 10.76 English sabins
-noise reduction can be increased by increasing the transmission loss, increasing the absorption of the receding room, decreasing the area of the barrier separating the 2 rooms, or some combo of the 3
The higher the STC rating
the better the wall is at stopping sound
Combined transmission
when a partition includes 2 or more types of construction like a door in a wall or a glass panel in a wall
can be found with the following:
-TLcomposite = 10log(Atotal/sum(tS))
-t=10-(TL/10) used to find the value of t if the value of transmission loss of the individual materials is known
Noise criteria curves
Can be used to specify the max amount of continuous background noise allowable in a space, to establish a min amount of noise desired to help mask sounds, and to evaluate an existing condition
Typical preferred noise criteria in dB
-concert halls, opera houses, recording studios = 15-20
-bedrooms, apartments, hospitals = 20-30
-private offices, small conf rooms = 30-35
-large offices, retail stores, restaurants = 35-40
-lobbies, drafting rooms, lab work spaces = 40-45
-kitchens, computer rooms, light maintenance shops = 45-55
Preferred noise criteria
has sound pressure levels lower than the NC curves on the low- and high-frequency ends of the chart
STC to the effect on hearing
-25 - normal speech can clearly be heard through barrier
-30 - loud speech can be heard and understood fairly well; normal speech can be heard but barely understood
-35 - loud speech is not intelligible but can be heard
-42-45 - loud speech can only be faintly heard; normal speech cannot be heard
-45-50 - loud speech is not audible; loud sounds other than speech can only be heard faintly is at all
Absorption of a material
defined by the coefficient of absorption, a, which is the ratio of the sound intensity absorbed by the material to the total intensity reaching the material; max absorption is 1.0, the absorption of free space
Absorption below .2
Reflective, if above its sound absorbing
sound absorption average SAA
overtaking the NRC rating on products
total absorption of a material is dependent on the area of the material and the material’s coefficient of absorption
A = Sa
the total absorption of a room is the sum of the various individual material absorptions
Increasing sound absorption within a space results in noise reduction
NR = 10log(A2/A1)
A1 is the original total room absorption in sabins and A2 is the total room absorption after the increase
Average absorption coefficient of a room
should be at least .20. Indoor-outdoor carpet has an AC of about .20 while heavy carpet on a concrete floor has an AC of about .30. Average AC above .50 is usually not desirable. Materials with lower values are suitable for large rooms, materials with higher values are suitable for small or noisy rooms
Doubling the amount of absorption in a room results in
a noise reduction of only 3dB
A reduction in reverberation time by 1/2
Best placement for absorptive materials
ceiling treatment for sound absorption is more effective in large rooms, whereas wall treatment is more effective in small rooms
Reverberation time
the time it takes the sound level to decrease 60 dB after the source has stopped producing the sound; the reverb time in seconds, T, is calculated using:
—T = 0.05(V/A) = 0.05(V/aS)
—V is the volume of the room in cubic feet
Space to preferred reverb time in seconds
-auditoriums (speech and music) - 1.5-1.8
-broadcast studios (speech only) - 0.4-0.6
-churches - 1.4-3.4
-elementary classrooms - 0.6-0.8
-lecture/conference rooms - 0.9-1.1
-Movie theaters - 0.8-1.2
-offices, small rooms for speeches - 0.3-0.6
-opera halls - 1.5-1.8
-symphony concert halls - 1.6-2.1
-theaters (small dramatic) - 0.9-1.4
Hydraulic Elevators
-Lifted by a plunger or ram set in the ground directly under the car and operated with oil as the pressure fluid
-the cylinder for the ram must be extended into the ground to a depth equal the the elevators height
-speed is limited; 25-150 ft/min
-only used for passenger and freight loads in buildings 2-6 stories high or about 50’
-single ram weight capacity is 2000-20,000 lbm; multiple-ram units weight capacity is 20,000-100,000 lbm
Electric elevators
-The most common for passengers
-cab suspended by cables, or ropes, that are draped over a sheave and attached to a counterweight; motor drives the sheave which transmits lifting power to the ropes by the friction of the ropes in grooves of the sheave
-also referred to as traction elevators
-250-1800 ft/min
-2000-5000 lbm capacity; higher capacities available for freight elev
Electric, Gearless traction elevators
use a direct current motor directly connected to the sheave; brake is mounted on the are shaft; those that are dependable and easy to maintain are used on high-speed elevators
Electric, geared traction elevators
used for slow speeds form 25-450 ft/min; high speed DC or AC motor drives a work gear reduction assembly to provide a slow sheave speed with high torque; provide a great deal of flexibility for slow-speed, high-capacity elevators
Control
the method of coordinating and operating all the aspects of elev service, such as travel speed, accelerating and decelerating, door opening speed and delay, leveling, and hall lantern signals
Single automatic operation
the simplest system; a single call button on each floor and a single button for each floor inside the car; only called when no one is using it; limited use and best for small buildings with little traffic
Selective collective operation
most common system; elev remembers and answers calls in one direction and then reverses and answer all calls in the opposite direction; when trip is complete the elev can return to a home landing; works well for light to moderate service requirements
Group automatic operation
best for large buildings with many elevators; the control of all elevators with programmable microprocessors to respond to calls in the most efficient manner possible
Destination floor guidance systems
newer; computer controls with AI to put riders into the same car who are going to the same floor or to floors near each other; each rider selects a destination floor in the lobby and the system assigns them a car; reduces total travel time and results in fewer stops for each car
Drive control
Controls the speed of the motor that drives the traction machine
Safety devices
-If power fails the brake is automatically applied
-if governor detects speed limit is exceeded the brake is applied
-safety rail clamps grid the side rails if an emergency
-car buffers stop a car’s motion if it over travels the lowest stop; not to stop a free-falling cab
-multiple ropes, escape hatches in the top, alarm buttons on the control panel, telephones for direct communication in an emergency
-if fire alarm is activated all cars go to first floor and switch to manual control
-min clear door opening width is 36”; controls no higher than 54” for side approach or 48” for front approach
the max number of passengers is directly related to the capacity in weight
-2000 lbm - 12 people
-2500 - 17
-3000 - 20
-3500 - 23
-4000 - 28
Number of elevators required
found by taking the total number of people to be accommodated in a five minute peak period and dividing by the handling capacity of one car; the interval, or average waiting time for an elevator to arrive, can then be checked to see if it is acceptable
—for offices its 30-35 seconds
—for hotels and apartments its 40-70 seconds or more
Methods to never have more than 6 cars in a group or 4 cars in a line
-divide elevators into banks that serve separate zones of the building
-sky lobby
-stacked or double deck elevator cabs
Hoistway
elevator shaft; fire resistive; has space for guide rails cables, counterweights, and various electrical and control devices
max of 4 elevator cars in one hoistway
Elevator pit
provides space for the car buffer, the compensating cables, and other equipment; gives room for maintenance under the cars
must have drain or sump and permanent lighting and access to get down there
Elevator doors
Center opening single speed doors are most common by side opening and 2 speed are also available
Machine rooms
-Best located directly above the hoist-way and must provide adequate space for the moto, sheave, brake, controller board, speed governor, floor selector mechanism, and motor generator
-must be about as wide as the hoist-way and 12-16’ deeper than the hoist-way; min ceiling heights 7’6” - over 10’
machine room less elevator (MRL)
has the motor control or within the hoistway rather than in a dedicated machine room; for some hydraulic electors or gearless elevators in low and mid rise buildings
—reduced noise and vibration
—elimination of the lubrication needed for traditional wire ropes
—the ability to place call buttons in the elevator door jambs, simplifying coordination with other trades
—shorter ordering lead times
—faster installation
Freight elevators
-Designed and intended to transport only equipment and materials and the passengers that need to handle the freight
-available in capacities of 2500-8000 lbm with some multiple ram hydraulic elev capable of 100,000 lbm
-speeds are 50-200 ft/min with 800 ft/min for very tall buildings
Escalators
-standard speed is 100 ft/min (120 ft/min for transportation and sports facilities)
-32, 40, and 48” sizes available with tread widths at 24, 32, and 40”; most common sizes are 32” and 48”
Crisscross arrangement
the up and down escalators from an X
—crisscross spiral arrangement: most common; after exiting at one floor they make a u turn to continue to the next floor
—crisscross walk around arrangement: all up escalators stacked vertically and all down escalators stacked vertically; the rider must walk around to the other area to enter the next escalator
Parallel arrangement
they are side by side and entrances are adjacent
—Parallel spiral arrangement: rider can reach the escalator to continue to the next floor with a simple u turn; total width of 4 escalators
—stacked parallel arrangement: forces the rider to walk around to the other side to continues to the next level but only 2 escalator wide
Stair tread and riser calculation
tread depth is from nosing to nosing, does not include the narrow depth from riser face to nosing above
2R + T = 25 or RT = 75 or R+T = 17 or T=20-(4R/3)
4 groups or classifications of soil
-sands and gravels: granular, low in plasticity; very good base for building foundations; good drainage
—sand: 0.002 - ¼”
—gravel: ¾- 3-½”
-Silt: fine grained, smaller than sand particles but bigger than clay; behave like granular but have some plastic behaviors; only adequate for foundations when reports show stability
-clay: smaller than silt particles; some cohesion or tensile strength and are plastic when wet; unpredictable- swells with water, shrinks when dry; only adequate for foundations when reports show stability, best if mixed with other types of soil
-Organic: vegetable or other organic material; poor base for foundation
Hard pan
unbroken mixture of clay, sand, and gravel; good base for foundations
Shale and slate
soft rocks with fine texture; second highest bearing capacity
Boulders
rocks that have broken off of bedrock
Bedrock
Solid rock that forms the earths crust; highest bearing capacity
Soil tests
determine the bearing capacity, water table level, and porosity
Core borings
undisturbed samples of the soil are removed at regular intervals and the type and material is recorded in a boring log which shows the material, the depth at which it was encountered, its standard designation, moisture content, density, and borehole testing results
Standard penetration test (SPT)
one of the most common borehole test; measures the density of granular soils and the consistency of some clays; 2” diameter sampler driven into the bottom of the borehole, the number of blows required to drive the cylinder 12” is recorded
Number of borings
depends on several factors but usually at min 4 borings are taken at the corners of the proposed building
Test pits
second common test; trenches dug that allow visual inspection of the soil strata and direct collection of undisturbed samples; usually only up to 10’ deep
Soil test requested by
by architect but paid for by owner; for information only; not part of the CD set
Other types of soil test
-Uber borings
-wash borings
-dry sample borings
-soil load test
Brownfield
A property whose redevelopment of reuses may be complicated by the presence or potential presence of a hazardous substance, pollutant, or contaminant; needs remediation which may be removal of soil and replacement
Karst region
landscape in which soluble rocks such as limestone, dolomite, and gyp have resolved, forming caves and other voids
Labs can test for what
-grain size and shape: determine the shear strength of the coil, its permeability, the likely result of frost action, and compaction ability
-liquid and plastic limits: the values give the compaction and compressibility values for cohesive soil
-specific gravity: used to determine the void ratio, which determines compressibility of the soil
-unconfirmed compression: values used to measure the shear strength for cohesive soil
-water content: used to get the compressibility and compaction values for cohesive soil
Soil classification
according to Unified Soil Classification System (USCS)
Bearing capacity specified by what
building code based on the soil type
Water in soil
-Can reduce the load-carrying capacity so large and expensive foundations may be necessary
-differential settlement can occur is there’s more moisture under one part than another
-foundations below the water table are subject to hydrostatic pressure which can put additional loads on the structure and can make waterproofing more difficult because it forces water in every crack
To increase bearing capacity and/or decrease settlement, the following methods of soil treatment can be used
-drainage
-fill
-compaction
-densification
-surcharging
-mixing
-geotextimes
Proctor test
fill samples are tested to determine a standard for compaction and use the optimum relationship of fill density and moisture content
Other soils considerations
-Frost: footings and foundations should be below the frost line to prevent the structure from lifting
-Expansive soil: clays tend to expand when they get wet and shrink when they dry; foundations must be isolated from these soils by pies or caisson foundation piers that bear on material below the expansive soil; concrete beams stretch between the piers
-repose: when soils are piled up they create a slope, the angles of the slope is the angle of natural repose and is the max practical angle for changing grades without using retaining walls
Unshored sides in excavation
should be no deeper than their natural angle of repose or not greater than a slope of 1-½ horizontal to 1 vertical; if not possible it must be shored
Rough grading
moving the soil prior to construction to approx levels of the final grades or adding or removing soil after construction; within 6-12” of the desired level
Finish grading
the final moving of soil prior to landscaping or paving where the level of the earth is brought to within 1” of the desired grades; often includes the placement of topsoil
Soldier beams and breast borders
-prior to excavation, steel wide flange soldier beams are driven at 6-10’ intervals to a length slightly deeper than the anticipated excavation
-as soil is removed, horizontal timbers 2-4” thick called breast boards or cribbing are placed between the soldier beams fo they bear against the inside face of the flange
-when excavation reaches a certain point, holes are drilled diagonally into the earth or deeper rock; rods or tendons are inserted into the holes and grounded into place; the tiebacks are connected to horizontal wales that hold the cribbing back against the pressure of the excavation
-as excavation proceeds more breast boards and tiebacks are added
-excavation is free from bracing and allows drilling of piers,forming of foundation walls, and other construction to proceed unimpeded
Braced excavation
-steel sheeting composed of interlocking Z shaped sections supported by continuous horizontal members called wales
-wales are supported by diagonal rakers that are anchored to the bottom of the excavation with steel or concrete heel
Underpinning
temp support existing foundations while they are being repaired or strengthened or when they are being extended to a lower level; needle beams supported by adjacent grade and hydraulic jacks temp support the building while foundation is constructed
Subsurface drainage
-To minimize subsurface water, the land around the building must be sloped to drain surface water before it soaks in; min slope of ¼ in/ft
-perforated drain tiles below ground should be laid around the footings at least 6” below the floor slab to collect water and carry it away to a storm sewer system, dry well, or natural drainage area; drain tile set in gravel bed and more gravel added on top; commonly know as a French drain or sub-drain
-gravel or open web matting can be places around the wall is hydrostatic pressure is a problem
-large gravel layer placed below slab to relieve pressure against floor
-waterproofing membranes can be used in conjunction with the drains and gravel is water is a significant problem
Concrete paving
-placed on compacted soil or a gravel bed and reinforced with welded wire fabric to resist temp stresses
-min 5” thick
-poured in section; expansion joints every 20’ with ½” premolded joint filler
Asphaltic paving
-includes bituminous paving
-subbase of course gravel overlaid with finer aggregate compacted and rolled then asphalt 2-3” thick laid overtop
Unit pavers
-can be concrete, brick, granite, and flagstone
-laid on a level compacted base of sand over crushed gravel; can also be laid on a bituminous setting bed over as poured concrete slab for more stability
Concrete sidewalks
laid over gravel base with control joints every 5’ and expansion joints every 20’; 4” thick; expansion joints where abutting buildings, curbs, paving, and other permanent structures
Deadman
a timber, plate, or similar object placed perpendicular to the face of the retaining wall and that serves to anchor the wall by means of earth friction or pressure
Concrete formwork
joints and ties are visible so design and method should be considered
Rustication strips
continuous pieces of neoprene, wood, or other material that when removed will show a deep reveal in the concrete; joints are often emphasized with this method
Form ties
metal wires or rods used to hold opposite sides of the form together and prevent their collapse; when the forms are removed the excess is twisted or cut off
Tie holes
made with cone shaped heads placed against the concrete form; when removed a deep round hole is left allowing the tie to be cut off below the surface of the concrete; can be left exposed or patched with grout
Insulating Concrete Forms
polystyrene foam forms that provide the formwork for poured concrete and remain in place after the concrete cures; finish materials applied directly to plastic or metal ties that are integral to the forms; speed construction and provide insulation in one operation; strong exterior wall above grade with good sound attenuation and less air infiltration
ICF varieties
-block: use foam blocks about the size of concrete blocks with interlocking edges and integral ties and can be stacked like simple building blocks; ties attached to plastic or metal strips used for attempt of finishes
-plank: use flat foam panels up to 4’x12’
-panel: use flat forms up to 12” high and 2-8’ long
F-number system (face floor profile numbers)
an electronic instrument is used to take multiple readings over 12” intervals and develop a statistical evaluation of the flatness and levelness of a floor, which is reflected in a single number value for each ranging from 10-150; a way to specify and measure the flatness and levelness tolerance of a floor
Water vapor migration
Through diffusion water vapor moves from areas of high vapor pressure to areas of low vapor pressure
How water moves through the slab
Capillary action
Water vapor moisture migration
-slabs on grade must have a vapor barrier under the slab to prevent moisture moving through
-low water cementitious materials ratio of the concrete mix can reduce water problems; max set to 0.45-0.50
-wait as long as possible for concrete to cure before applying sealants; a min of 6 weeks
Vapor barrier thickness
should be at least 10 mil thick
Welded wire fabric
Used for temperature reinforcement in slabs; consists of cold-drawn steel wires set at right angles to each other and welded at their intersection; usually in a square pattern with spacing of 4” or 6”
5 types of cement
-Type I: standard cement or normal cement; used for most general construction where the special properties of other types are not needed
-Type II: modified cement; used where a modest amount of sulfate resistance is needed and the heat of hydration needs to be controlled, such as dams or other massive structures
-Type III: high-early-strength cement; used where a quick set is needed; also has a higher heat of hydration so suitable for cold-weather concreting
-Type IV: low-heat cement; used in massive structures to minimize cracking; very slow setting
-Type V: sulfate-resisting cement; used for structures that will be exposed to water or soil with a high alkaline content
Too much water reduces the concrete’s strength
water equal to 25% of the weight of the cement and an extra 10-15% more to make a workable mix; usual minimum water-cementitious material ratio (w/cm) is about 0.35-0.40 by weight or about 4-4.5 gallons of water per 94 lbm sack of cement
Laitance
occurs if too much water is added which is a chalky surface deposit of low-strength concrete
Design strength
specified by the compressive strength of the concrete after it has cured and hardened for 28 days; typically 2000 psi, 3000 psi, and 4000 psi
Air-entraining agent
forms tiny bubbles in the concrete to increase the workability and durability of the concrete and improves its resistance to freezing and thawing cycles; also helps reduce separation of the components as the mix is poured into forms
Accelerator
speeds up the hydration of the cement so that the concrete achieves strength faster; allows faster construction and reduces the time needed for protection in cold weather
Plasticizer
reduces the amount of water needed while maintains the needed consistency for correct placement and compaction; reducing the water makes it possible to mix higher-strength concrete
Retarder
slows down the setting time to help reduce the heat of hydration
Waterproofing agent
decreases the permeability of the concrete
Fly ash
a waste material obtained from coal-fired power plants; improves workability, reduces temperature rise, minimizes bleeding, reduces permeability, inhibits alkali-silica reaction (ASR), and enhances sulfate resistance
ground-granulated blast-furnace slag
produced from the material formed from molten slag that is a by-product of iron and steel manufacturing; a 25-50% substitution for Portland cement is common; improves workability, decreases the need for water, increases setting time ; benefits large pours and hot weather pours; reduces bleeding, improves resistance to sulfate and chloride attack, and can prevent damage from ASR; has a higher strength than Portland cement
Silica fume
collected by filtering the smoke created during the production of silicon and ferrosilicon metals; added to concrete in proportion of 7-10% by weight of the cement; decreases permeability, increases compressive strength, improves abrasion resistance, and reduces bleeding
Pozzolan
siliceous or aluminosiliceous material that reacts chemically with the calcium hydroxide released by the hydration of Portland cement to form various cementitious compounds; decrease permeability, increase strength, improve resistance to ASR and sulfate attack
Curing concrete
-proper temp and moisture conditions should be maintained for at least 7 days up to 14 days; cover with plastic, use sealing compounds, or continually sprinkle the surface with water
-gains 70% of its strength within the first 7 days, final 28 day design strength depends on the initial curing conditions
-keep the concrete from freezing; freezing can make it lose ½ its strength; cover with plastic sheets and the heat of hydration will keep it warm enough
-alternatively use Type III cement in very cold conditions
slump test
measures the consistency of the concrete; concrete placed in 12”H cone, poured out next to the cone and measure in inches the amount the concrete slumps; 2-6” is desired
Cylinder test
measures compressive strength; samples are taken while concrete is placed and put in a cylinder mold that is 6”D and 12”H and are moist cured and tested in the lab; compressive strength in pounds per square inch is calculated and compared with the value used in the design of the structure; 7 day results are usually 60-70% of 28 day strength
Core cylinder test
used when portion of the structure is in place and cured but needs to be tested; cylinder drilled out and tested in lab
Kelly ball test
aka ball penetration test; hemisphere mass of steel with a calibrated stem is dropped onto a slab of freshly laid concrete; amount of penetration of the ball into the concrete is measured and compared to ½ the values of the slump test
Impact hammer test
nondestructive way to test concrete strength after it has hardened; spring loaded plunger snaps against a concrete surface and the mount of rebound is measured; gives approx reading of the concrete strength
K-slump test
¾” tube containing a floating scale; placed on the wet concrete and the scale is pushed into the mixture and released; the distance the scale floats out directly measures the consistency of the concrete
Calcium chloride test
aka moisture dome test; one of the most common; inexpensive and easy to complete; standard mass of calcium chloride is placed below a sealed plastic cover; after 60-72 hours the calcium chloride is weighed and compared with its pre test weight; one test for every 500-1000 SF of slab area
hygrometer test
aka relative humidity test; determines the moisture emission by measuring the relative humidity of the atmosphere confined adjacent to the concrete floor; pocket of air trapped below a vapor-impermeable box and a probe in the device measures the RH; usually moisture resistant floors should not be installed unless RH is 75% or less
polyethylene sheet test
seal an 18” x 18” sheet of plastic to the floor to trap excessive moisture; after 16 hours a visual inspection is made of the floor and the sheet; presence of visible water indicated it’s in sufficiently dry for finishes
Mat test
24” x 24” sample of vapor-retardant floor finish applied with adhesive and sealed with tape; after 72 hours visual inspection is made; if the mat is firmly bonded or difficult to remove the level of moisture level is considered to be sufficiently low for installation of the finishes
Electrical impedance test
uses meters that measure conductance and capacitance; probes placed on the concrete and the percentage of moisture content is the slab is read out directly
alkali-silica reaction, ASR
strongly alkaline cement begins to dissolve the sand and rock within the concrete; the chemical reaction produces a gel-like material that creates pressures in the pores of the concrete surface that can buckle or blister floor finishes; ASR risk reduced by specing aggregates not susceptible to ASR, using low-lime cement, proper curing, or not finishing in the concrete with a hard trowel surface; use SCM’s to improve resistance
Titration test
determines the level alkalinity in concrete; grind portions of the concrete, mix powder with demineralized water and perform lab chemical analysis
Concrete, as-cast finishes
-rough form finish
-smooth form finish
Concrete, architectural finishes
-form liner
-scrubbed: exposes the course aggregate
-acid wash: exposes full color of aggregate
-water jet: expose the aggregate
Concrete, tooled and sandblasted finishes
-bush hammering: rough heavy texture
-Grinding: smooths it out, similar to terrazzo
-applied: such as stucco
-sandblasted finishes: expose fine and coarse aggregates
Concrete, rubbed finishes
-smooth
-grout cleaned: grout applied all over and smoothed out to remove defects
Concrete slab finishes
-strike off: to level the floor roughly
-floating: bring cement paste to surface, for a smooth surface
-float finish: no further work is done after floating; sandpaper like texture appropriate for exterior surfaces or where smooth is not needed
-light steel-troweled finish: steel trowel used several hours after floating; further consolidates concrete
-hard steel-troweled finish: continues consolidation and densities top ⅛” of the concrete for a very smooth surface
-broom finish: dislodges fine aggregate and makes a rough-textured surface useful for slip-resistance on outdoor slabs
-superflat floor finish: usually hard steel-troweled but for industrial warehouse
-stamped finish: embossed and decorative
Control joint
weak section created for normal temp and stress cracking to occur there instead of elsewhere; tooled when concrete is still wet by saw cutting or using premolded sections in the formwork; ¼ the slab thickness
Construction joint
where there are 2 successive pours; located at a point of minimum shear; reinforcing extends from one pour to another; where water leakage can occur so prefab elastomeric waterstops that extend from the first pour into the second can be inserted
Expansion joint
entire sections of concrete can move independently of one another; joint must be able to move in 2 direction; usually extend through the entire structure so no rigid connection between any 2 components of the building
Isolation joint
allows 2 adjacent sections to move independently of one another; not as complex as expansion, premolded joint material between 2 separate concrete pours; often used to separate columns from slabs and slabs from foundations
Precast, prestressed concrete
Makes a more efficient and economical structural section, reduces cracking and deflection, increases shear strength, allows longer span and greater loads
Pretensioning
cable or wire placed in the forms and tensile force is applied; once concrete is cured the cables are cut transferring the compressive force to the concrete
Post-tensioning
hollow sleeves or conduits included with the forms; high-strength steel tendons placed in conduits and stressed with hydraulic jacks after the concrete has cured; if unbounded left alone (usually for slabs and beams, parking structures, and slabs on grade); if bonded the tubes are removed and the space if filled with grout (usually for bridges and heavily loaded beams in buildings)
Masonry cement
a prepared mixture of Portland cement and pulverized limestone; not as strong or expensive as Portland cement but has greater plasticity; suitable for low rise building veneers and interior non-load-bearing applications
Mortar types
-Type N: common for exterior, above-grade walls exposed to severe weather; also used for laying soft stone masonry
-Type S: suitable for at- or below-grade applications due to its higher compressive strength
-Type M: highest compressive strength and recommended for harder stone and walls bearing heavy loads
-Type O: generally limited to interior non-load-bearing walls, tuckpointing, and historic structures
Building/common brick
used where color or finish doesn’t matter; graded according to its resistance to exposure:
—severe weathering SW
—moderate weathering MW
—negligible weathering NW
Facing brick
For exposed locations; usually available in SW and MW grades and further classified into:
—FBS, for general use where a wide range on color and variation in size are acceptable or required
—FBX, used when a high degree of mechanical perfection, narrow color range, and minimal variation in size are required
—FBA, nonuniform in color, size, and texture
Hollow brick
available in SW and MW grades; further classified according to its appearance:
—HBS for general use where range of size and color variation is acceptable or desired
—HBX when a high degree of mechanical perfection, narrow color range, and minimum variation in size are required
—HBA nonuniform in color, size, and texture
Brick sizing
most common size is 3 ⅝”T x 2 ¼”H x 7 ⅝”L with ⅜” mortar joint makes it a mod size of 4” x 8”; 3 courses equal 8” or one standard concrete block
Wythe
continuous vertical section of a wall one masonry unit in thickness
Belt/string course
a continuous band of masonry across the facade of a building or entirely around it differentiated by projecting from the face, being a different color or style, or being made of a different type or thickness
Sill course
a belt course located at the level of the window sills
Joints recommended for exterior
Concave, flush, and vee
Horizontal expansion joint placement
below beams and slabs above brick and below shelf angles that support intermediate sections of brick
Single wythe wall
consists of one layer of brick that acts as either a load-bearing or no-load-bearing wall; not reinforced; max ratio of unsupported height or length to thickness cannot exceed 20:1 for a solid wall or 18:1 for a hollow masonry wall
Cavity wall
two wythes of brick separated by an air space; tied together with galvanized metal wall ties or continuous horizontal reinforcement placed 16” OC vertically; inside wythe often built with CMU to save cost and speed construction
Reinforced grouted wall
two wythes of brick but the cavity contains vertical and horizontal reinforcing bars and is completely filled with grout; can carry heavier loads, have higher unsupportive heights, and are better able to resist lateral loading, compared to cavity walls
Veneer wall
a single wythe of brick attached to some other type of construction, usually a wood frame wall in residential construction or a steel stud backup wall for commercial construction; masonry for decorative and weather-resisting purposes
Reglet
preformed metal shape cast into concrete wall and set flush with the wall to allow the insertion of the edge of flashing and a sealant
Weep holes
located 24” OC horizontally in the lowest course of brick to allow any water that penetrated the wall to drip out; usually small prefab tubes or vents embedded in joint space
4 categories of concrete block
-hollow, load bearing
-solid, load bearing
-hollow, non load bearing
-solid, non load bearing
Concrete block size
dimensions are 4” nominal module; widths are 4”, 6”, 8”, 10” or 12” and lengths are 8”, 12”, and 16”; all ⅜” less than nominal
Concrete block reinforcement
horizontal reinforcement required every 16” OC
Equivalent thickness
the solid thickness that would result if the concrete contained in a hollow unit were recast without core holes
Stone coursing
-Rubble: used with little or no shaping
-squared stone: stone with slightly shaped edges resulting in vertical joints
-ashlar: highly shaped stone; also referred to as cut stone; thick pieces
-range masonry: arranges stones in uniform courses for the entire length
-Broken range masonry: stones are coursed for short distances
-random masonry: devoid of coursing or any attempt to align vertical joints
-veneer stone: ¾” - 1 ¼” sheets applied over a structural support system
Dimension stone
cut stone; steps, trim, coping, and belt courses use this
Fabricating metal, basics
-casting
-rolling
-extruding
-drawing
-bending
-brake forming
-spinning
-embossing
Fabricating metals, annealing
metal is reheated and slowly cooled to obtain a more ductile metal which will have improved its machinability and cold-forming characteristics
Fabricating metals, quenching
heating the metal to a certain temp and then rapidly cooling it by complete submersion is water or some other liquid; strengthens the steel
Fabricating metals, tempering
similar to quenching but not rapidly cooled; see to improve the strength and workability of steel
Fabricating metals, case hardening
produces a hard surface steel over a relatively softer core
Galvanic action
the corrosion resulting when dissimilar metals come in contact with each other in the presence of an electrolyte such as moisture
Electrolysis
a mild electric current is set up between the 2 metals, gradually corroding one while the other remains intact
Ferrous metals
Metals that contain a substantial amount of iron
Wrought iron
iron with very low carbon content (less than 0.30%) and a substantial amount of slag; similar in chemical composition to low-carbon steel; soft, ductile, and resistant to corrosion; limited to ornamental iron work such as gates, grilles, and fences
Cast iron
iron with a carbon content above 2%; very hard but brittle
Steel
High strength, ductility, uniformity of manufacture, variety of shapes and sizes, and ease and speed of erection
as carbon is added, the strength increases but the ductility decreases
Ductility
allows steel to withstand excessive deformations due to high tensile stresses without failure; useful for earthquake-resistant structures
Bonderize
coat metal with an anticorrosive phosphate solution in preparation for the application of paint, enamel, or lacquer
Quenching and tempering
after quenching the steel is brittle so its tempered again at a lower temp and cooled slowly
Case hardening
a process for heating a metal and diffusing a gas or liquid, commonly carbon or nitrogen, into its surface, creating a thin layer of a harder alloy; then the metal is given a heat treatment
Stainless steel
most stainless steel is passive but can become active when the chromium-oxide layer is active or when exposed to certain chemical agents
Passivity
a layer of nonreactive molecules does not allow metal ions t the surface to migrate into solution; given to the stainless steel by a layer of chromium-oxide
Weathering steel
an alloy that contains a small amount of copper; when exposed to moisture in the air or from rain it develops a protective oxide coating with a distinctive sepia-colored finish; runoff should be designed to not stain other materials
Nonferrous metals
Metals that do not contain iron
Aluminum
Aluminum by itself is soft and weak but alloyed with manganese, zinc, magnesium, and copper improves its strength and hardness
high strength-to-weight ratio makes it desirable for building materials
Anodizing
an electrochemical process that deposits an integral coating on the metal; can be scratched
Copper and copper alloys
-Resistance to corrosion, workability, high electrical conductivity
-2 primary alloys:
—bronze: alloy of copper and tin
—brass: alloy of copper and zinc
-Used for electrical wiring, hardware, curtain walls, piping, gutters, roofing, window and door frames, wall panels, railings, and ornamental purposes
Wide flange members
-H-shaped used for both beams and columns; width of the flange is greater than that of standard I-beams
-wide-flange sections designated with the letter W followed by nominal depth in inches and the weight in lbm/ft
American standard I-beams
-relatively narrow flange width in relation to their depth an the inside faces of the flanges have a slope of one in six; the actual depth in any size group is also the nominal depth
-designated with the letter S then depth and weight follow
-usually used for beams only
American standard channel sections
-flange on 1 side of the web only; depth is constant for any size group, extra weight is added by increasing the thickness of the web and the inside face of the flanges
-designated by a C followed by depth and weight
-typically used to frame openings, from stair stringers, or where a flush side is required
Structural tees
-cut either a wide-flange section or I_beam in half
-if cut from wide flange designated by WT
-if cut from an I beam designated by ST
-often used for chords or steel trusses
Steel angles
-equal or unequal leg options; used in pairs as members for steel trusses or singly as lintels in a variety of applications
-designated by letter L followed by the lengths of the angles and then the thickness of the legs
-used for miscellaneous bracing of other structural members
Square, rectangular, and round tubes
-used for light so lumens and s members of large trusses or space frames
-structural tubing: available in several different wall thicknesses; designated by its actual outside dimensions
-structural pipe: available in standard weight, extra strong, and double-extra strong; all have a standard wall thickness depending on the size; designated by nominal diameter but actual outside dimension is slightly larger
Bars
any rectangular section 6” or less in width with a thickness of 0.203” and greater, or section 6-8” wide with 0.203” and greater
Plates
any section over 8” wide with a thickness of 0.203” and over or sections over 48” wide with a thickness of 0.180” and over
Light-gauge metal framing
-Consists of steel members with thicknesses from 10 gage to 25 gage
-used for interior partitions, exterior bearing and no bearing walls, joists, rafters, and similar framing
-noncombustible, easily cut and assembles, does not shrink or otherwise decay
-Stud depths are 1 ⅝, 2 ½, 3 ⅝, 4, and 6”
-joists available in 6-14” depths ; capable of spanning up to 40’
Softwoods used for
Structural and rough carpentry
Finish carpentry lumber used
Both softwoods and hardwoods
Strength of lumber
-dependent on the direction of the load relative to the direction of the wood’s grain
-strongest when the load is parallel to the direction of the grain, such as with compressive load on a wood column
-weakest when horizontal shear force is introduced
Yard lumber
for structural purposes and rough framing
Factory and shop lumber
for making door frames, windows, and finish items
Yard lumber classification
-boards less than 2” x 2” or more
-dimension lumber 2-5” x 4-12” or more
-timber 5” or more x 5” or more
Factory and shop lumber grading
according to defects that affect the appearance; usually divided into select and common grades
Lumber dimensioning
Lumber ordered and priced by the board foot; a measure of a quantity equal to a piece 12” wide by 12” long by 1” thick, nominal sizes used
Lumber nominal vs actual
1” = ¾”
2” = 1 ½”
4” = 3 ½”
6” = 5 ½”
8” = 7 ¼”
10 = 9 ¼”
12 = 11 ¼”
Fiber saturation point
when the cell walls are completely saturated but no water exists in the cell cavities; averages about 30% moisture content
Dry lumber
moisture content cannot exceed 19%
Kiln dry
moisture content cannot exceed 15%
Wood shrink most in which direction
Perpendicular to the grain
Light frame construction
Closely spaced members such as 2 x 4 or 2 x 6 studs for walls and partitions with nominal 2” thick members for floor and roof joists; beams may be built-up sections of nominal 2” lumber or heavy timber or steel
platform frame system (aka western framing)
uses separate studs for each floor of the building with the top plates, floor joists, and floor framing of the second floor constructed before the second floor wall studs are erected; each floor can be completed and used for construction the next floor, shorter studs cost less
balloon frame system
continuous wall studs from foundation to second floor ceiling; vertical shrinkage is minimized because most of the construction is parallel to the direction of the grain where wood shrinkage is least
Sheathing
-this panel material attached to framing to provide lateral support, increase rigidity, and provide a base for applying exterior finishes
-for structural purposes, most often consists of plywood or particle board nailed to the wood studs of joists
-insulating sheathing can be used where lateral stability is not critical
Particleboard
-composed of small wood particles, fibers, or chips of various sizes mixed together and formed under pressure into a panel
-preferred for backing and framing of finish carpentry and arch woodwork
-less expensive and more dimensionally stable the plywood
Oriented strand board (OSB)
-engineered panel made from precision-cut wood strands a max of 4” long and 0.0027” thick, arranged in layers at right angles to one another and bonded with resin waterproof glue
-primary strength along the orientation of the chips on the face layer or parallel to the length of the panel
-acceptable for short term weather exposure
medium density fiberboard (MDF)
-panel made from wood particles reduced to fibers combined with resin
-most dimensionally stable of the mat-formed panel products
Hardboard
panel product composed of inter-felted fibers consolidated
Blocking
wood framing installed between main structural members such as studs of joists to provide extra rigidity or to provide a base for nailing other materials
Bridging
bracing between joists that prevents th joist from buckling under load
Fire stops
barriers installed in concealed spaces of combustible construction to prevent the spread of fire caused by drafts
Plywood web joists
-Like wood I-beams
-manufactured in the same depths as standard solid wood joists and deeper
-have a much higher load-carrying capacity than wood joists
-efficient use of wood products
-minimal shrinkage, ease of handling, uniformity of size and shape
-made with plywood or OSB web piece fitted into grooves of chord members made of solid wood or laminated veneer lumber
Laminated veneer lumber
-Aka thin glued-laminated framing or structural composite lumber
-made by gluing thin veneers of lumber together to build up a strong, rigid, dimensionally stable member
-used for headers or beams and in place of studs
Trusses
-Factory made assemblies consisting of relatively small wood members (2 x 4, or 2 x 6 usually) held together with toothed plate connectors
-can span up to 40’ for floor trusses and 70’ for roof trusses
Structural Insulated Panels (SIPs)
-Structural Insulated Panels (SIPs)
-decreased construction time (⅓ less than stick-built)
-Improved insulation value with no thermal bridges
-reduced air infiltration
-stronger than conventional stud and sheathing construction
-dimensional stability
-Strength in compression, bending, shear, and uplift
-green product, requires less wood, uses renewable resources for the facings, improves thermal performance, and reduces construction waste
Composite decking
-mixture of small wood fibers and plastic formed into planks used for exterior decks and railings; additions may include colorants, stabalizers, and fungicides
-lasts longer than wood and easier to maintain
-strong, durable, splinter free, and usually of recycled materials
Cross-Laminated TImber
-Layers of dimension lumber at right angles to form a thick structural panel; odd number of layers; thicker pieces of wood than what’s used in plywood
-very strong; resist axial, bending, and racking loads; provide diaphragm action for lateral loads
-spans up to 25’ can be achieved without intermediate supports
-environmentally sustainable and no job site waste
Glued-Laminated Construction
-Used where larger wood members are required for heavy loads or long spaces and simple sawn timber pieces are not available
-also used where usual structural shapes are required and appearance is a consideration
-standard widths and depths, 1 ½” actual depth pieces used so overall depth are multiples of that; ¾” pieces used if tight curve is needed
-allowable stresses are higher than those for solid, sawn timber; can be loaded in either direction to the laminations
Planking/decking
-solid or laminated timber that spans beams
-2, 3, 4, and 5” widths
-tongue-and-groove edging
-intended to span greater distances between beams rather than closely spaced joists like sheathing; 4-20’
-easy installation, attractive appearance, efficient use of material
Nailing schedules
found in the building code give the min size, number, and penetrations of nails for specific applications such as nailing studs to sole plates, joists to headers
Bolts
-Common for joints of moderate to heavy loading
-washers used under the head and nut of the bolt to prevent crushing the wood and to distribute the load
Hardwoods used almost always for what
Woodwork
Lumber heartwood
Comes from the center
Lumber sapwood
Comes from the perimeter
Lumber cutting, plain/flat sawing
most efficient use of the log; least expensive; cut flat or parallel to the centerline all the way through; cathedral pattern
Lumber cutting, quarter sawing
cutting the log into quarters and then sawing perpendicular to a diameter line; more uniformly vertical pattern; twist and cup less, shrink less in width, hold paint better, and have fewer defects
Lumber cutting, rift sawing
saw cuts from a quarters log are always radially cut to the center of the tree; great deal of waste; more expensive than quarter sawing; produces a more consistent vertical grain pattern
Most arch woodwork is made from what?
Veneer
Veneer
thin slice of wood cut from a log and glued to a backing of particleboard or plywood, normally ¾” thick
5 methods for veneer cutting
-plain sawing
-quarter slicing
-rotary slicing
-half-round slicing
-rift slicing
Rotary slicing
log mounted on a lathe and turned against a knife peeling off a continuous layer of veneer; very pronounced grain pattern that is usually undesirable; lest waste
Half-round slicing
similar to rotary but the log is cut in half and the veneer is cut slightly across the annular growth rings; pronounced grain pattern showing characteristics of booth rotary-sliced and plain-sliced veneers
Rift slicing
quartering a log and cutting at about a 15 degree angle to the growth rings; results in a straight-grain pattern and often used with oak to eliminate the appearance of markings perpendicular to the direction of the grain
Flitch
individual veneers come from the same piece of log, called a flitch
Scribe piece
oversized piece of plastic laminate or wood that can be trimmed in the field to follow any minor irregularities of the wall
Flush cabinets
face of drawer or door installed flush with the frame of the frame; expensive because extra care needed to fit the pieces; doors and drawers may sag and bind against the frame
Flush overlay cabinets
fronts overlap the face frame of the cabinet; edges of the fronts are separated only enough to allow operation without touching, usually about ⅛” or less; fronts are the only part visible and the it flush with each other; also needs great care to fit properly
Reveal overlay cabinets
edges of adjacent doors and door fronts are separated enough to reveal the face frame behind; less expensive than flush overlay
Lipped overlay cabinets
part of the floor or drawer overlaps the frame and covers the joint between the 2 pieces
Ways to match adjacent veneer leaves
-book matching
-slip matching
-random matching
Book matching
most common; every other piece of veneer slice is turned over so that adjacent leaves from a symmetrical grain pattern
Slip matching
consecutive pieces are places side by side with the same face sides being exposed
Random matching
places veneers in no particular sequence and even veneers from different flitches may be used
3 ways to match veneers within a panel is bookmatched
-running match
-balance match
-center match
Running match
alternates bookmatched veneer pieces regardless of their width or how many must be used to complete a panel
Balance match
veneer pieces are trimmed to equal widths; must be an odd or even number of veneer pieces in each panel
Center match
an even number of veneer leaves of uniform width so there’s symmetry about a veneer joint in the center of the panel
3 ways panels can be matched in a room
-non matched, premanufactured
-sequence matching
-blueprint matching
Not matched, premanufactured
least expensive; panels (4’ x 8’ or 10’) are assembled from a single flitch that yields from six to twelve panels; field cut to fit around doors, windows, and other obstructions; some loss of grain continuity
Sequence matching
uses panels of uniform width manufactured for as specific job and with the veneers arranged in sequence; moderate loss of grain continuity if some panels must be trimmed to fit around doors or other obstructions
Blueprint matching
most expensive; panels manufactured to precisely fit the room and line up with every obstruction so that grain continuity is not interrupted; veneers from the same flitch are matched over doors, cabinets, and other items covered with paneling
Stiles
Vertical frame pieces
Rails
Horizontal frame pieces
Colorthrough laminates
made with decorative papers throughout the thickness so the result is a solid color; dark line is not visible at the edge of sheets when trimmed
Fire-rated laminates
comply with Class 1 or A ratings as long as the appropriate substrates and adhesives are selected
Chemical resistant laminates
special formulation of the laminate materials five these products additional resistance to strong chemicals found in labs, medical facilities, and photographic studios; horizontal and vertical thicknesses and can be post-formed for curved surfaces
Static dissipation laminates
where static control is required like hospital operating rooms, electronic manufacturing plants, and computer rooms; provide a conductive layer in the sheet; prevent the buildup of static charges and channel them away
Metal faced laminates
limited number of metal finished available; don’t have the same wear resistance as real metal so should only be on vertical surfaces subject to little abuse; made with standard woodworking equip and cost less than real metal; difficult to fabricate spall, detailed items with finely crafted edges
Natural wood laminates
thin veneers of actual wood bonded to standard type of laminate kraft papers and resins; laminate can be specified to provide untreated wood ready for finishing or with a protective layer of melamine resin
thermoset decorative paneling
decorative overlay pressed onto a cellulose substrate such as particleboard or MDF; decorative surface is fused to the substrate of particleboard in contrast to decorative surface of high pressure laminates that are thin veneers adhesive bonded; sometimes called low-pressure laminates; trade name Permalam
Standing trim
woodwork of a fixed length intended to be installed as a single piece of wood; door frame trim, door stops, window casings, etc
Running trim
woodwork of a continuing length that must be installed in several pieces fitted end to end; base molding, cornices, stair rails, and soffits
Moisture content for woodwork
the optimum moisture content of architectural woodwork for interior applications is 5-10%
Wood material classification
wood generally considered Class C material unless treated with a fire retardant
Lacquer
coating with a high nitrocellulose content modified with resins and plasticizers dissolved in a volatile solvent
Varnish
consists of various types of resinous materials dissolved in once of several volatile liquids; when high solids content is specified the finish becomes opaque
Polyurethane
synthetic finish that gives a very hard, durable finish; difficult to repair or refinish; offer superior resistance to water, to many commercial and household chemicals,m and to abrasion; available in sheens from dull satin to full gloss
Polyesters
synthetic finish that five the hardest,most durable finish possible; polyester can be colored and are available only in a full-gloss sheen; very difficult to repair and refinish outside the shop but give very durable finish with as much as 80% hardness of glass
Water based stains
yields uniform color but raise the grain
Solvent based stains
dries quickly and doesn’t raise the grain but are less uniform
Dampproofing
-The control of moisture that is not under hydrostatic pressure
-always applied on the positive side, or wet side, of the elements and are generally applied by sprayer, brush, roller, or trowel
Dampproofing methods
-Admixtures: added to concrete to make it water repellent; may reduce the strength of the concrete but make it less permeable to water
-bituminous coatings: asphalt or coal-tar pitch materials applied to the exterior side of the foundation wall; brushed or sprayed on; applied either hot or cold and should be applied to smooth surfaces; will not seal cracks that develop after they are applied
-cementitious coating: one or two coats of Portland cement mortar can be troweled over the surface of masonry of concrete foundation walls; mortar coatings used over rough walls to provide a smooth surface for the installation of other dampproofing materials, but can also be used alone; iron often added to the mortar so it expands while the mortar shrinks to make it a tighter seal
-Membranes: include built-up layers of hot or cold applied asphalt felts or membranes of butyl, polyvinyl chloride, and other synthetic materials; typically used for waterproofing walls subject onto hydrostatic pressure because their cost and the difficulty of applying them is not usually warranted for simple dampproofing
-plastics: silicone and polyurethane coatings are available but usually reserved for above-grade dampproofing
Waterproofing
-The control of moisture and water that is subject to hydrostatic pressure; may include protecting parts of structures that are below the water table
Waterproofing placement
-positive side waterproofing: the most common; waterproofing material placed on the side of the elements exposed to water, the exterior of a foundation wall, after the element is in place
-negative side waterproofing: applied after the element is in place but to the side of the element that is not exposed to water
-blind side waterproofing: applied before the elements is in place; such as on a shored excavation against which a concrete foundation wall will be poured
Waterproofing materials
-sheet membranes: built-up layers of bituminous saturated felts similar to roofing, or single ply membranes of synthetic materials such as butyl, polyvinyl chloride, and others; may be loosely applied and attached to nailing strips but more effective systems are adhered to the foundation on the positive side
-Fluid-applied systems: include modified asphalts, urethanes, and other synthetics; applied in liquid form to provide a continuous, seamless membrane; applied on the positive side
-cementitious systems: Portland cements, sand, and some type of waterproofing agent; can be applied either on the positive or negative side but more effective on positive
bentonite systems: assembly of bentonite clay inside kraft paper packages or plastic liners in panel form; -bentonite expands in the presence of moisture preventing water from getting past; often combined with geotextile fabrics and can be both blind side and positive side application
Crystalline waterproofing
during concrete hydration the mixture comes in contact with water and expands to fill the pores, capillaries, and micro-cracks in the concrete with an insoluble crystalline formation; concrete become self-healing; can be positive or negative side application; brushed or sprayed on or added to concrete as an admixture
Rain screen system
exposed surface provides protection from the elements, but is used in conjunction with an air space behind it and a water-tight membrane and/or air barrier inside the air space, which is vented to the outside so the pressure is equal on both sides of the rain screen; minimizes the movement of water due to pressure differentials caused by wind or other forces; moisture that does penetrate is prevented from entering the backup wall with a vapor barrier and flashing, and is drained Down the air space and out through weep holes
Vapor retarders
-A material used to slow the transmission of diffusion of water vapor between spaces; are not insulation but play an important role in preserving the effectiveness of other insulating materials
-dew points the point at which water condenses from the vapor
-Problems arise when warm moist air cools and reaches its dew point and the condenses
-barriers may also function as air barriers if it is appropriate to place them in the same position within the wall
Vapor diffusion
the slow movement of water molecules through vapor-permeable materials; warm moist air tends to migrate to cooler drier air
Perm rating
less than 0.1 - vapor impermeable
0.1 - 1 - semi-impermeable
1 - 10 - semipermeable
10 or over - permeable
Cold areas vapor control
vapor barriers should be placed on the warmer inside of the insulation; Vapor-permeable air barrier should be places outside the insulation to prevent air infiltration while allowing any accumulated moisture to dry out
Warm-humid areas vapor control
vapor retarder should be placed on the warmer outside of the insulation; should also serve as air barrier, or in other words the air barrier should be vapor-impermeable
Mixed climates vapor control
the vapor-permeable air barrier should be placed outside the insulation and no vapor retarders should be used
Dew point analysis
a temp gradient line is developed from outside to inside based on the R-values (temp resistance) of the individual building materials in a specific condition; helps find the point in the wall where the interior temp of the wall and the dew point meet
Rain screen, drained and back-ventilated
exterior cladding does not prevent water from penetrating due to pressure differentials
Rain screen, pressure-equalized, a true rain screen
the air cavity is vented enough to equalize the pressure on both sides of the exterior cladding to reduce the amount of wind-driven water into the cavity and onto the drainage plane; a continuous air barrier is required
The lower a material’s k-value or C-value
the better its insulating qualities, and higher R-values indicate a better insulating value
long-term thermal resistance
a rating method for foam insulation products; the thermal resistance value o a closed-cell for an insulation product measured after storage for 5 years under prescribed lab conditions; this value should be used for heat transfer calculations and is commonly found in insulation product literature
Loose fill insulation
-used in places where it is difficult to install other types of insulation, such as in the cells of concrete block walls, plumbing chases, and attics
-settle after installation; cellulose settles 20%, rock wool and fiberglass settles about 2-4%
-too heavy in the ceiling can cause drywall to sag
-require installation of a vapor retarder or vapor barrier
Loose fill insulation types
-mineral wool
-cellulose insulation
-cotton insulation
-fiberglass insulation
-perlite insulation
-vermiculite
Batt insulation
-Fibrous material placed on or within a kraft paper carrier
-the paper also serves as a vapor retarder
-sometimes also comes with a reflected surface
Board insulation
organic given way to inorganic because they have higher insulating values
Board insulation types
-expanded polystyrene: EPS
-extruded polystyrene: XPS
-Polyisocyanurate insulation: polyiso
-polyurethane
Sprayed foam insulation
-Uses polyurethane or polyicynene as the base material; components of the foam are delivered in 2 separate tanks and are mixed at the spray head and then expand to produce low-density foam that adheres to the cavity
-excellent R-value and conforms to the shape of the cavity and seals all cracks and openings thoroughly
-IBC requires spray applied foam to be separated from the interior of the building with an approved thermal barrier, such as ½” thick gyp
Sprayed foam insulation types
-spray polyurethane insulation
-icynene
-cementitious foam insulation
Sprayed fiber insulation
completely filled the cavities where it is installed and does a better job of filling voids than batt insulation
Sprayed fiber insulation types
-cellulose
-fiberglass
-rock wool
Radiant barrier
single sheet of highly reflective material, usually aluminum, that faces an open air space; reduces the passage of thermal radiation, most often by blocking summer heat gain, but sometime sot help retain winter heat; barrier place on outside of conventional thermal insulation
Reflective insulation
when a radiant barrier is combined with a backing of insulation
Have 2 properties that make them good for insulation: reflectivity and emissivity
for opaque materials, the sum of the reflectivity and emissivity is 1
Roofing squares
when describing size, estimating, and ordering roofing materials, roofing area is referred to in squares; a square is equal to 100 SF
Terneplate
steel sheet coated to resist corrosion; usually with zinc
Tin roof reaction
tin reacts with asphalt; tin or terneplate roofs use rosin-sized paper in place of asphalt felt
Membrane roofing slope
should have at least ¼ in/ft slope
Built-Up Bituminous Roofing
-can be installed over a nailable or non-nailable deck
-3-5 layers of saturated roofing felt then laid over, each layer bedded in roofing cement so felt doesn’t touch felt; number is determined by the type of deck and the length of guarantee period desired
-final coating of bituminous material placed over entire roof and covered with gravel
Nailable
base sheet of unsaturated felt is nailed to the deck and covered with a coating of roofing cement
Non-nailable
the base sheet is omitted and a base coat of roofing cement is applied
Single ply roofing types
Ethylene propylene diene monomer EPDM
chlorosulfonated polyethylene CSPE
Polyvinyl chloride PVC
Thermoplastic polyolefin TPO
Sealants
flexible materials used to close joints between materials
Caulking
often used to designate low-performance sealants employed where little movement is expected
Sealant classification
classified depending on the max amount of joint movement they can tolerate:
—low +/- 5%
—intermediate =/- 12%
—high 25% or more
Hinge jamb
The hinge or pivot side
Strike side/jamb
the jamb where the door closes
Door hand or handing
the standard method of referring to the way a door swing is called
Determined by outside of door
Reversible or nonhanded
hardware that can work on any hand of door
Left-hand door
when standing outside, if the hinges are on the left and swings away from you
Right hand door
when standing outside, if the hinges are on the right and swings away from you
Left hand reverse
when standing outside, if the hinges are on left and it swings toward you
Right hand reverse
when standing outside, if the hinges are on right and swings towards you
3 most common types of metal doors
-flush: single, smooth surface on each side
-sash: contains one or more glass lites
-louvered: has an opening with metal slats to provide ventilation
Door frame fire rating
where a fire rating over 20 minutes is required, steel frames are almost exclusively used
Hollow core wood door
made of one or three plied of veneer on each side of a cellular cardboard interior; used where light use is expected and cost is a consideration; no fire resistance and poor acoustical properties
Solid core wood door
made with a variety of core types; may be particleboard, stave core (solid blocks of wood), or mineral core for fire-rated doors; used for fire-resistance, acoustical barriers, security, and superior durability; fire rating of 20 minutes to 1 ½ hours; mineral core are 45 minutes, 1 hour, or 1 ½ hours
Wood door thicknesses
1 ⅜” thick hollow core; 1 ¾” thick solid core; 2 ¼” available for large, exterior doors and acoustical doors
Wood frames
may be used in 20, 30, and 45 minute fire for assemblies but a 1 hour rated door must be in a rated metal frame
Glass doors
Usually ½” or ¾” thick with fittings and operating hardware
glass must be tempered; holes, notches, or other mods made before glass is tempered
Hardware function groups
-hanging the door: hinges, pivots, and combo pivots and closers
-operating the door: handles, latch sets, push plates, and pull bars
-closing the door: door closers and combo pivots and closers
-locking the door: lock sets, dead bolts, flush bolts, electric locks, and other special devices
-sealing the door: weather stripping, sound seals, and smoke seals
-protecting the door: kick plates, corner protection, and similar materials
Hinges, full mortise
most common; both leaves fully mortised into the frame and edge of door
Hinges, half mortise
one leaf surface-applied to the frame and the other mortised into the edge of the door
Hinges, half surface
one leaf mounted on the face of the door and the other mortised into the frame
Hinges, full surface
both leaves are applied to the faces of both the doors and frame
Special hinges, raised barrel hinges
used where there’s no room for the barrel to extend past the trim; offset to allow one leaf to mortise into the frame
Special hinges, swing clear hinges
allows the door to swing 90 degrees so the full opening is available, common in healthcare
Latchset
holds the door in place but has no provision for locking
Lockset
has a special mechanism that allow the door to be locked with a key, thumb turn, or electronic device
Latches and locks, mortise
installed in a rectangular area cut out of the door; generally more secure than a bored lock and offers a wider variety of locking options; allow the use of deadbolt and latch bolt which can be retracted with a single operation; variety of knob and lever designs can be used
Latches and locks, preassembled
aka unit locks: come from a factory as a complete unit; slid into a notch made in the edge of the door and require little adjustment; often found in older buildings but seldom used in new buildings
Latches and locks, bored
aka cylindrical locks or latches: installed by boring holes through the face of the door and from the edge of the door to the other bored opening; easy to install and less expensive than mortise locks but offer fewer operating functions; generally used in residential and small commercial projects
Latches and locks, interconnected
have a cylindrical lock and a deadbolt; the 2 locks are interconnected so that a single action of turning a knob or lever handle on the inside releases both bolts
Backset
distance from the edge of the door to the center line of the doorknob or pivot of a lever handle; standard backsets are 2 ¾” and 5”
Panic hardware
used where required by building code for safe egress during a panic situation; push bars extending across the width of the door operate vertical rods that disengage latches at the top and bottom; rods can be surface mounted or concealed; when panic hardware is listed for use on fire door assemblies its called fire exit hardware
Closers
pneumatic devices that automatically return a door to its closed position after it is opened; control the distance a door can be opening and protect the door and surroundings from damage; surface mounted on the door or head frame or concealed in the frame or door; selection depends on the type, size, and weight of the door, the frequency of operation, the visual appearance desired, and the door height clearance required; can also be integral with pivots mounted in the floor or ceiling, either center hung or offset
Closers, fire protection
available with built-in fire and smoke detectors so it can be held open during normal operation but will close when smoke is sensed; exit doors must have closers but can usually be allowed by code to be held in the open position if they close automatically on the activation of a smoke detector
Astragals
vertical moldings or wooden strips used between double doors to seal the opening, act as a door stop, or provide extra security when the doors are closet; may be fixed or removable to allow for a wide opening when moving furniture
Coordinator
device used with double doors that are rabbeted or that have an astragal on the active leaf; mounted in or on the head of the frame, coordinating the closing sequence of the 2 doors so that they close completely rather than having the leaf with the astral close first, preventing the other leaf from closing completely
Flush bolts
used on the inactive leaf of a pair of doors to lock the doors; may be surface mounted or mortised into the edge of thedoor; active leaf then closes to the locked inactive leaf, but both can be opened when needed; not allowed on exit doors
Automatic door bottoms
devices that are mortised or surface applied to the bottom of the door to provide a sound or light seal; when the door is open, the seal is up; as it closes, a plunger strikes the jamb and forces the seal down
Electric lock
maintains a mortise or bored lock set in the locked position until a signal is activated by a regulating device which can include wall switches, push buttons, card readers, key switches, computerized controls, auto time devices, security consoles, etc
Electric latch
normal position to hold the latch so the door cannot be opened until activated; from the inside exit can happen regardless of the position of the electric latch; no power is run to the door, all wiring is in the door jamb
Electric bolts
can be mounted in the strike jamb or head; in locked position a bolt extends from the unit into a strike in the door, a push button, card reader, or other device retracts the bolt; generally not allowed on exit doors
Fire doors hardware
fire doors must be self-closing or auto closing
—self-closing door has a closer or other device that returns it to the closed position after someone passes through
—auto closing door are normally held open but auto close on activation of a smoke detector, fire alarm system, or other approved device
when closed, a fire door must be secured with an active latch bolt
must use steel hinges of the ball bearing type
astragals used if pair of doors is used
Glass in fire doors
if glass is used it must be wire glass set in metal frames or special fire-protection-rated glass
wire glass 45 min rating
Aluminum window frames
susceptible to galvanic action and high heat conduction; galvanic action controlled with proper selection of fasteners and flashing; heat transmission prevented by specing frames with thermal breaks
Float glass
smooth, flat surface; also annealed glass
Heat strengthened glass
2x the strength of annealed glass at same thickness; used where subject to solar induced thermal stresses and cyclic wind loading
Tempered glass
4x stronger than annealed glass; used in hazardous location; if broken falls to thousand of very small pieces
Laminated glass
2 or more pieces of glass bonded together by an interlayer of polyvinyl butyrate resin; when broken the interlayer holds the pieces together even though the glass itself may break; bullet resistant, high security; safety glazing and can be used in hazardous locations; where sound control is needed
Tinted glass
aka heat-absorbing glass; reduces solar transmittance ; should not be used where partially in sun and partially out of it because can crack, usually heat strengthened or tempered for this reason
Low-iron glass
reduces the light green cast in normal glass, exceptional clarity, optimal light transmission, and excellent color transmission
Reflective glass
clear or tinted coated with a thin layer of metal or metallic oxide; to save energy by reflecting solar radiation
Insulating glass
2 or 3 sheets of glass separated by a hermetically sealed air space; used where heat loss is a problem
Patterned glass
vision diffused
Wire glass
wire embedded; cannot be tempered so is not safety glazing for hazardous locations
Spandrel glass
opaque; conceals floor and ceiling structure in curtain wall
Low-emissivity glass
selectively reflects and transmits certain wavelengths of the electromagnetic spectrum
Energy efficient glazing
reduce heat loss and/or heat gain through windows, reducing the energy needed to maintain a comfortable indoor temp without reducing the amount of visible light transmitted
Electrochromic glazing
general term for this that change from opaque to transparent with an electric current
—electrochromic glazing
—suspended particle device glazing
—polymer-dispersed liquid crystal film glazing
Fire-rated glazing
4 types in addition to wire glazing:
—clear ceramic glass; can be laminated to be more safety
—tempered fire-protective glass; max 30 minute rating; safety
—2 or 3 layers of tempered glass with a clear polymer gel between
—glass block; specifically rated
Glazing labels by manufacturers
-D means the glazing is for use in doors and has been tested in accordance with NFPA 252
-H means it meets the hose stream test
-T means it meets the temperature rise requirements
-OH means the glazing is appropriate for fire window openings
-W means the glazing is appropriate for use as a wall
2 common methods of applying plaster
Metal lath (expanded diamond mesh, paper-backed diamond mesh, flat rib lath, high rib lath)
Gypsum board lath
Plaster application
first coat is scratch coat, next is brown coat, last is finish coat; ¼”, ¼”, ⅛”; two-coat work combines the scratch and brown coats
Gypsum thicknesses
¼”, ⅜” and ⅝” thickness
¾” for 2 hour rating
Types of tiles
-Ceramic tile: usually thin, made from clay of a mixture of clay and other ceramic materials; either glazed or unglazed
-quarry tile: glazed or unglazed, usually with face are of 6 squared inches or more; made from clay or shale by extrusion
-ceramic mosaic tile: formed by the dust-pressed or extrusion method; ¼” to ⅜” thick, and has facial area of less than 6 inches square
-dust pressing: uses large presses to shape the tile out of relatively dry clay
Classification of tile
-Classified based on size: under 6 SI (square inches) is mosaic tile, over 6 SI is wall tile
-glazed or unglazed non-mosaic tile made by extrusion is quarry tile
-glazed or unglazed tile 6 SI made by the dust-pressed ethos is paver tile
Full mortar bed tile installation
tile floor and mortar are separated from the structural floor with a cleavage membrane so they can move serparaetly
Thinset tile installation
thinset is laid on a substrate consisting of cementitious panels nailed to the subfloor; commonly a glass-mesh mortar unit specifically made for tile install
Installation of terrazzo
-Sand cushion method: the best way to avoid cracking, because the finish system is physically separated from the structural slab by a membrane; terrazzo can moved independently of the structural system
-bonded method: if floor deflection or movement is not expected
-monolithic method: where thickness of the installation is a problem
-thinset method: where thickness of installation is a problem
Acoustical ceiling tile
-recycled content may range from 50% - 90%
-perforated or fissured somehow to absorb sound; do not prevent sound transmission to any appreciable extent
Ceiling fire rating
-No combustible materials and plastic wires must be in metal conduit above plenums space
-if fire rated, they must be part of a complete rated floor-ceiling or roof-ceiling assembly; cannot be rated by themselves
6 seismic design categories
labeled A (least restrictive) through F (most restrictive)
No special seismic design is required for
Structures in seismic design category A or B
ceiling with areas less than 144 SF
gyp wallboard suspension systems
plaster and lath ceilings
Seismic design ceilings for categories D, E, and F
the ceiling cannot provide lateral support for partitions
Float floor
some glued directly to a stable concrete or wood subfloor, some glued to each other along the edges but lay loose over thin foam padding
Static-free flooring
Capable of conducting electrostatic discharge to ground
2 subtypes: conductive and static dissipative; defined by their electrical resistance; static dissipation is more resistant
grounding is required; usually done by placing copper strips under the flooring and connecting the strips to an earth ground, such as steel structure, or to an electrical ground, which is part of the electrical system
electrically conductive rubber flooring is one of the best because it meets all industry standards and it works with any type of footwear
The Brewster system: aka Prang system
familiar color wheel that organizes the colors by their relationships with the primary colors
the Munsell color system
defines color more precisely than the color wheel; uses 3 scales in 3 dimensions to specify the values of hue, value, and chroma; five principal hues (yellow, gree, blue, purple, and red) and five intermediate hues halfway between the principal hues
