Integration Of Buidling Materials & Systems Flashcards
HVAC system sizing
Sometimes the cooling equipment chosen will be slightly undersized in order to keep initial costs low, knowing that some occasional minor extremes will be tolerated
active systems are often used in combo with passive systems; can often possibly reduce the size of the active equipment
Mechanical spaces, variables affecting space requirements
Scope of the system (local, centralized, or district)
Type of HVAC system
Building size
Building type
Passive systems use
Scope of the system, local
local system serves one zone and used for small building or for specific areas of a building
-Several local systems can be used if more than one zone is required in small or moderate sized buildings (ex. Commercial gas-fired heaters)
-ex. Residential furnace, window mounted air conditioner
-least space needed
Scope of the system, centralized
Centralized system serves several zones from one location
-common in commercial a and institutional buildings of moderate to large size
-there can be several centralized systems in one building if the building is very large or for reasons of efficiency
-most space needed
Scope of the system, district
district system serves several buildings by a single plant
-ex. Central steam plant on a college campus
Type of HVAC system
-all-air system; needs the most space
-all-water system; needs the least amount of space
-air-water system; no return ducts needed
-electric systems and direct expansion systems
Building size
affects the volume of heating and cooling needed
Building type
consider the individual control needs and provisions for ventilation and positive pressure on the building types
Passive system use
passive systems influence the size of equipment needed because it can reduce or eliminate the capacity needed from the equipment
Mechanical Spaces, Preliminary sizing, medium to large building with all-air or air-water system
mechanical room should be 3-10% of the total building area being served
-includes space for boilers, chillers, fans, fuel (if needed), and related pumps and piping
Mechanical Spaces, Preliminary sizing, medium to large building with all-water system
mechanical room should be 1-3% of the total area
Mechanical Spaces, Preliminary sizing, cooling towers
when needed are .2-1% of the building area served and located on the roof or outside the building
Mechanical Spaces, Preliminary Sizing, Boilers and Chillers
-usually at least 2 boilers so one can operate while the other is being serviced
-chillers usually located in the same room as boilers
Air Handling Units
-AHUs included in all-air and air-water systems
-AHU uses water from the boilers and chillers to heat or cool the air
-AHU located in the fan room
Fan Rooms
-fan room ideally located next to an exterior wall, but can be placed further inside the building as long as fresh air and exhaust air can be carried in and out by ductwork
-fan room equipment includes fans, filters, humidifiers, preheat coils for cold climates, return air ducts, outside air intakes, and exhaust ports, as well as dampers and a mixing box to control the mixing of fresh or, return air, and exhaust air
—equipment is heavy, noisy, and causes vibration
-multiple fan rooms can accommodate multiple building uses, seasonal changes, or zoning requirements
Location of equipment in small or low-rise building
mechanical equipment is usually best located in the basement or on the ground floor
Best location for boilers and chillers
located on lower levels due to structural requirements; best located away from sensitive areas due to noise
High-rise building mechanical equipment location
mechanical equipment rooms may be located in the basement along with a primary fan room that distributes air upward
-boilers and chillers may be located in the basement with smaller fan rooms located on each floor; allows greater smoke control in case of fire
Best location for mechanical rooms in general
mechanical room located next to an outside wall to allow for the intake of combustion air and near a service door or removable panel for the replacement of boilers and other equipment; located near the chimney
Round ducts
more efficient and maintain air pressure better
Rectangular ducts
make better use of the space available above ceiling and in vertical duct chases
Vertical ducts
can be centrally located and feed horizontally out, or can be located along the perimeter, and feed horizontally in
Horizontal trunk ducts
should follow the paths of building circulation systems
static head (or static pressure)
the amount of pressure that must be applied to overcome frictional resistance and cause air to flow through the system; measure in inches of water
fan rooms should be located to minimize the length of ductwork needed
-the longer the ductwork the more friction there is
-larger ducts keeps the pressure lower but means more space is needed for the ducts
-increasing the size of the can raise pressure but results in higher initial costs, higher operating costs, and more noise
Low pressure duct space sizing
allow a cross-sectional area of 10-20 SF for every 10,000 SF of floor space served
Coordination of mechanical systems with project design details
the clear space between the ceiling and the structure can be tight, sometimes coordinating the placement of ducts and recessed light fixtures is difficult or not possible in the space provided; low-voltage or low-clearance light fixture may be specified
Mixing box
controls the air that flows into a space from the main air supply line; also located in the plenum; mixing box reacts to thermostat, adjusts the air’s velocity and the noise it makes
Mixing box, terminal reheat system
cool air enters the mixing box at a fixed temperature, the mixing box contains a hot water coil that can add heat as needed
-identified easily but the air ducts and copper pipes leading into the mixing boxes
Mixing box, dual duct system
the mixing box receives cool air and hot air from 2 separate ducts; it mixes and distributes the air to ducts that service individual rooms or spaces
Mixing box, variable air volume system
the control device is called a VAV box; VAV box receives air at a constant temperature and varied the airflow rate as needed to maintain the desired temperature
Relocating mixing boxes
can be expensive due to their size and connection with ductwork and thermostats
Access flooring
a false floor of individual panels raised above the structural floor with pedestals
-more commonly covers electrical, communication, and computer wiring, but can sometime be used to house some types of HVAC ductwork that serve individual workstations
Residential construction ducts and plumbing
small ducts and plumbing pipes are typically run within the walls and between floor joists or in crawl spaces or attics; large horizontal ducts may be run below the floor joists and a dropped ceiling or furred-down space must be built to conceal them
Square air diffusers
common in suspended ceilings because their inexpensive and easy to install
slot air diffusers
used when the appearance of the device needs to be minimized or when space available is limited; provides uniform air supply along a window line
Plenum
the space between a suspended ceiling and the structural floor or roof
used as a space for ductwork, sprinkler piping, plumbing piping, wiring, signal systems, speakers, and recessed lighting
Mid- and high-rise building plenums
it make more economic sense to minimize the plenum height to reduce the floor-to-floor height
Plenum levels
-uppermost level is the structure of the building
-next level is mechanical ducts, mixing boxes, and other HVAC equipment; smaller branch ducts may need 12-16” of space
-next level down is the plumbing and sprinkler piping; usually 4-6” of space needed
-lowest level is for recessed luminaires; ranges from 9-12” for compact fluorescent downlights, to 4-5” for standard fluorescent fixtures; LED and compact fluorescent fixtures can reduce the depth further
-depth of suspended ceiling is usually about 2”
plenum can be used as return air space
in this case use of exposed combustible material within the plenum is prohibited
-electrical wiring would need to be in steel conduit
access doors
small, steel doors with frames that are opened through use of a thumb latch or key to provide access in a ceiling to equipment
Thermostats
-placed away from exterior walls, heat sources, or other areas that may adversely affect their operation
-48” aff, but coordinate location with light switches and other nearby wall-mounted control devices
Coordination with ceiling items
air supply register should be placed near windows and other sources of heat loss or heat gain, while return air grilles should be placed away from the supply points to provide good heat and air circulation throughout
Window coverings and air supply
-can interfere with supply air diffusers or other heating units near the window
-window could crack if heat buildup is excessive
Acoustic separation
special detailing or construction may be needed to create a continuous sound seal around the floor and ceiling, above the ceiling, and along the perimeter wall
Water pressure from a city main
is 50 psi; must be reduced by the friction if the system and still be high enough to operate fixtures
Flush valve psi needed
10-20 psi
Shower psi needed
12 psi
Pressure in a column of water
Increases in proportion to depth
Static head
express water pressure in terms of the height of a column of water; ex. A column of water 1’ height exerts a pressure of .433 psi at its base, so a pressure of .433 psi is equivalent to 1’ of static head; 1 psi is equivalent to 2.3’ of static head
2 primary types of water supply systems
Upfeed and downfeed
the choice is usually based on the height of the building and the pressure needed to operate the fixtures
Upfeed system
uses pressure in the water main to directly supply the fixtures
there is always some friction in the system and some pressure must be available to work the highest fixture, so the practical limit on building height is 40-60’
Downfeed system
water from the main is pumped to storage tanks near the top of the building and flows to the fixtures by gravity; more often used where the building is too tall for an upfeed system; maximum height of a zone is from 60 psi or about 138’
Upfeed and downfeed systems
sometimes the lower floors of a high-rise building are served by an upfeed system and the upper floors are served by a downfeed system
Direct Upfeed system (tankless system)
several pumps are used together and controlled by a pressure sensor, when demand is light, only one pump operated to supply the needed pressure, when the demand increases, the pressure drop is detected by the pressure sensor and other pump is signaled to start
medium sized buildings can use it
Water supply system components
consists of piping, fittings, valves, and other specialized components
Piping material
piping can be made of copper, steel, plastic, or brass
Union
a special fitting that connects 2 rigid sections of pipe and that can be easily unscrewed to allow for repairs or addition to the piping system
gate valve
seals a metal wedge against 2 metal parts of the valve; used where control is either completely on or off; no turns so has low friction loss
globe valve
used where water flow is variably and frequently controlled, such as with faucets or hose bibs; a handle operated a stem that compresses a washer against a metal seat; water must make 2 90 degree turns so the friction loss is high
check valve
works automatically and allows water flor in only one direction where, for example, back flow might contaminate a potable water supply
angle valve
where water control in sinks and lavatories is needed a single-handle faucet is used
water hammer
the noise caused when a valve or faucet is closed too quickly, causing the water moving in the system to stop abruptly and the pipes to rattle; prevented by air chambers and shock absorbers
air chamber
a length of pipe installed above the connection to the faucet that cushions the surge of water
shock absorber
performs the same function as an air chamber with a manufactured expansion device
pressure reducers/ pressure regulators
needed on fixtures if the supply pressure is too high, over about 60 psi; too high water pressure can cause wear on a fixture
pressure relief valves
safety devices designed to open when pressure exceeds a predetermined max; used on water heaters and similar equipment where excessively high pressures could cause damage or explosion
flow restrictor
a device to reduce the amount of water that comes out of. Tap or other fixture; used on showe heads and sinks to limit water use
Most r emote fixtures
After the various pressure losses are deducted from the available pressure at the water main, there. Must still be adequate pressure at the most remote fixture
Pressure loss in pipes
depends on the diameter of the pipe and on the flow rate, which is typically measured in gallons per minute; pressure loss due to friction within the pipe and friction is greater for smaller diameters and for greater flow rates
demand load
aka maximum possible flow; the flow rate that would be needed if every fixture in the system were in use at the same time; found by adding up the load values for all the fixtures
water supply fixture units
how the load value for a fixture is measured
fixture unit
a unit flow rate approximately equal to 1 CF/min
probable demand
aka peak demand, maximum probable flow, or maximum expected flow; the maximum flow rate that can be expected under typical conditions
used to design the water supply system
Finding probable demand
tables and graphs are available that relate the demand load (in fixture units) to the probable demand (in gallons per minute)
Once probable demand is known
this value can be used with a chart that shows how flow rate, pipe size, pressure loss due to friction, and velocity are related
used to choose the smallest diameter that will handle the needed flow rate without losing the pressure needed to operate
Using the table of estimated demand
find the probable demand in gallons per minute, and then read across to the intersection with one of the pipe diameter lines; if total friction loss is too great, select a larger pipe size and perform the calculation again
Flow rate for sound sensitivity
velocity at more than 10 ft/sec is too noisy; for sound sensitive areas don’t go above 6 ft/sec
Thermal expansion in piping
-allow for expansion of piping, especially for long lengths of piping
-there are also in-line expansion fittings
most efficient way to reduce the need for irrigation
use plants that can grow with the climate’s natural precipitation
Irrigation design
should be designed as efficiently as possible; timers, rain sensors, and tensiometer (measures the moisture content of the soil at the plant’s roof zone)
Two-pipe circulating system
can be used to reduce the need to run water until the hot water makes it to the pipe
all fixture are connected to both a supply pipe and a return pipe; the natural convection in the system keeps the water slowly circulating; hot water rises to the uppermost fixtures and cools as it falls down to the water heater to be reheated; pumps may be needed if there isn’t enough room for circulation
Size of the water heater
based on the total daily and peak hourly hot water demands of the building
Larger building water heaters
for larger buildings a separate storage tank is needed in order to meet demand, while a smaller boiler actually heats the water
recovery rate
the number of gallons per hour of cold water that can be heated to the desired temperature
demand load calculated
only from those fixtures that use hot water
Pipe size minimums
in no case can the pipe size be less than the minimum size given in the plumbing codes
Water heater temperature setting
water heaters are set to keep the water at the highest temperature that is needed at the point of use
Water temperature comfort
water above 110 degrees becomes uncomfortable to the touch
direct heating
brings the water into contact with surfaces heated directly by flame, hot gases, electricity, or solar radiation
Indirect heating water heater
uses another medium to transfer the heat from its source to the surfaces that are in contact with the water
3 basic types of heating systems
Storage tank
Tankless
Circulating
storage tank system
the same tank is used both to heat the water and to store it for use
tankless system
water is quickly heated as it is needed and immediately sent to where it is needed
circulating system
the water is heated in one place and then moved to a separate tank for storage until needed
2 types of drainage
Sanitary drainage
Storm drainage
sanitary drainage
includes any drainage that may include food or human waste
storm drainage
involves only runoff from roof drains, landscaped areas, and the like
storm drainage does not need to be treated
Drainage Systems
designed to safely carry away sewage to a private or municipal disposal system
Drainage systems consist of the following parts
Trap
Drainage piping
Vent
Air gap
Vacuum breaker
Stack
Drain
Sewer
Trap
-located at every fixture and designed to catch and hold a quantity of water, which forms a seal that prevents sewage system gases from entering the building
-usually installed within 2’ of the fixture but may be installed at slightly greater distances depending on the size of the pipe
-connected to the drainage piping, but also connected to vents
Vent
-pipes that lead from the drainage system to the outside air, typically through an opening in the roof
-allow built-up sewage gases to escape instead of bubbling through the water in the traps
-allow pressure in the system to equalize so that waste being discharged does not create a siphon that drains the water out of the traps
Air gap
-used as a safety feature
-faucets are always mounted with their outlets at least 2” above the highest possible level of wastewater
Vacuum breaker
prevents siphonage on fixtures where the water supply is below the rim of the fixture by closing when backward water pressure is present
Stack
-a vertical pipe that carries wastewater down to the bottom of the building
-if wastewater includes human waste it is called soil stack
-stack must extend through the rood and be open to the outside ai; called a stack vent
-vents must also be open to an exterior; vents on lower floors connected to a vent stack that runs parallel to the soil or waste stack
Drain
-All stacks are connected to a horizontal drain at the bottom of the building
-from within the building to a point 3’ outside the building, this is called the house drain or building drain
-From 3’ outside the building to a main sewer line or private disposal system , the horizontal pipe is called the house sewer/building sewer
-cleanouts provided where stack connect with the house drain to allow for maintenance; also required outside the building for maintenance of the house sewer
Drain, waste, and vent (DWV) pipe
piping designed for drainage systems
-available in copper, cast iron, and plastic
backflow preventers
such as backwater valves; keep wastewater from reversing flow and backing up into fixtures, which could contaminate the water supply of cause the basement to flood
sump pit and sump pump
installed when plumbing fixtures must be below the level of the house drain and house sewer; collects the sewage and pumps it to a higher level when’re it can flow by gravity to a sewer
floor drains
collect water in shower rooms or in places where overflow is likely
interceptors
collect foreign matter at the source instead of allowing it to enter the sewer system; common types are grease traps, plaster traps, and lubricating oil traps
sizing of drainage pipes
based on flow rate expressed in fixture units
drainage flow rate
expressed in drainage fixture units (dfu)
Plumbing fixture location
fixtures should be located as close to main plumbing lines as possible
Drains slopes
drains must slope at least ¼ in/ft, but ⅛ in/ft is allowed for pipes larger than 3”
max distance from a trap to the nearest vent
Plumbing code limits it
Island fixture venting
connects directly above the waste line where the trap arm discharges; the vent is carried up above the. Bottom of the sink and then looped horizontally and downward below the floor line; below the floor line the vent pipe runs horizontally to the nearest vent stack
air admittance valve placement
can be placed above the vertical waste line in the island to vent the sink
wet columns
areas where hot and cold supply and drainage risers are located
chase wall
consists of 2 rows of studs separated by several inches, the exact dimension being determined by the largest pipe or duct that has to be concealed
sink carrier
steel framework inside a chase wall that carried the weight of wall mounted sinks
toilet carrier
similar to sink carrier and supports wall mounted toilets
Chase wall thickness
chase wall with fixture on 1 side should be 12” thick and a chase wall with fixtures on both sides should be 16” thick
private disposal system components
consists of a septic tank, and a leaching field
Septic tank
collects the sewage and allows the solid matter to settle to the bottom
effluent
the liquid portion of sewage, drains into the distribution system where it seeps into the ground
size of septic tank
determined by the amount of Daily flow; based on number of bedrooms and bathers or by sewage flow in gallons per day
leaching field
an area where effluent seeps from the drain tiles into the soil
size of leaching field
based on the ability of the soil to absorb the effluent; determined by a percolation test
Minimum distance between a leaching field and a well
100’
Minimum distance between a septic tank and a well
50’
Minimum distance between a leaching field and a building
10’
waste stabilization ponds
4-8’ deep and act as holding basins for secondary wastewater treatment
advanced integrated wastewater pond system
the wastewater is exposed to different conditions to encourage the breakdown and removal of organic matter
facultative pond
the wastewater is exposed to aerobic activity near the surface and anaerobic activity near the bottom
second pond
contains a high level of algae, which produces oxygen that promotes further aerobic activity
settling pond
more than half the algae settle out
maturation pond
water rest to allow pathogenic bacteria or human origin to die
Storm drainage, private systems
drywells can be connected to the drain leaders with underground pipes
slope land ½ in/ft away from the foundation
drywell
a large, porous, underground container where water collects and seeps into the soil
drain field
similar to a leaching field; use if dry well is not enough
Storm drainage, municipal systems
-collects water from street gutters, catch basins, and individual taps from private buildings and land developments
-carried the water by gravity to natural drainage areas such as rivers, lakes, or oceans
retention pond
designed to contain the max expected runoff and then slowly release the water to the storm sewer system; may have small outlets at one end such as a dam or drain to a low point in the middle of the pond, where a catch basin, or grate, covers the entrance to a pipe
Drains, Gutters, and Downspout Sizing
the sizes are determined based on the area of the roof or paved area drained and the maximum hourly rainfall
Projected area
the horizontal area defined by the edges of the roof without regard to the slope
Used when calculating the roof area of a sloped roof
3 major objectives of fire protection and life safety
the protection of life, the protection of the property, and the restoration and continued use of the building after the fire
preventing fires
includes limiting the use of combustible building and finish materials and avoiding hazardous situations
early fire detection and alarm
sufficient warning must be given so that occupants can leave the building safely and so that fire fighting can start before the fire has spread
planning for the quick exiting of occupants
occupants should have a safe exit route from anywhere in the building
containing the fire
achieved through choice of building materials, compartmentation, and smoke control
suppressing the fire
achieved through sprinkler systems, standpipes, and other methods
Compartmentation
-can be used to create places of refuge where occupants can wait until the fire is extinguished or they can exit safely
-provides time for fire suppression to begin
Code requirements for fire separation
codes require fire separation between different occupancies, between use areas and exits, ad between parts of a building when the maximum allowable area is exceeded
also applies to whole buildings; fire ratings on exterior walls, limit the location of buildings on property, and either limit the size of exterior openings or require their protection when a building is near other structures or property lines
Smoke Control
Containment, exhaust, and dilution
containment devices
include smoke dampers, fire dampers, gaskets on fire doors, and automatic-closing fire doors
passive smoke control system
has a series of smoke barriers arranged to limit the migration of smoke
active smoke control system
an engineered system that uses mechanical fans to produce pressure differentials across smoke barriers or to establish airflows to limit and direct smoke movement
curtain board/draft stop
vertical panel made from fire-resistive materials that is attached to the ceiling immediately adjacent to an opening; minimum of 18” from the ceiling
IBC requirements for automatic smoke and heat vents
IBC requires automatic smoke and heat vents in one-story Group F and S occupancies over 50,000 SF and in Group H occupancies over 15,000 SF in a single-floor area; and above stages that are more than 1000 SF in area and in atriums
fusible link
small piece of wire that melts at a certain temperature and acts as a switch to open a vent, sprinkler head, or other fire-prevention system element
In the event of a fire
in the fire area the supply and return ducts are closed, and the smoke is exhausted to the outside; in the refuge area, the return and exhaust ducts are closed and supply air is added to create positive pressure
Pressurized spaces
stairways and vestibules
IBC requires sprinklers in which buildings
buildings over 75’ high and in hotels
wet pipe systems
kept filled with water at all times; when the temperature reaches the trigger point at any sprinkler, the system responds immediately; most common
Flow detector placement
flow detectors are placed on every zone of sprinkler piping; when a sprinkler head opens, the detector senses the movement of water and sends a signal to an annunciation panel or fire control center so the fire department knows where the fire is
Trigger point temperature
typically between 135-170 degrees
dry pipe systems
used in area subject to freezing; pipes are filled with compressed air or nitrogen until one or more heads are activated, allowing water to flow; can also be activated by a valve connected to a fire alarm
pre-action systems
similar to dry-pipe but the water is allowed into the system before any sprinkler head has opened; an alarm is activated simultaneously; the sprinkler head does not open immediately, there is a short delay that allows firefighters to respond; used where water damage is a concern; the early alarm allows the fire to be put out before any sprinkler head opens
deluge systems
activate all the sprinkler heads in an area at once, regardless of where the fire is detected; all the sprinkler heads are kept open and the pipes are kept empty; when an alarm is activated, valves automatically open, releasing water into the pipes and flooding the space; used in high hazard areas where a fire is likely to spread rapidly
siamese connection/splitter
a wye-shaped pipe fitting installed close to the ground on the exterior of the building; allows 2 fire hoses at the same location to connect to the standpipes and sprinkler system of a building
NFPA 13
Standard for the Installation of Sprinkler Systems
classifications of fire hazard levels
light, ordinary, and extra; determines the required spacing of sprinklers and other regulations
Light level fire hazard
their must be one sprinkler for each 225 SF of floor area if the system is hydraulically calculated; if its not then its one sprinkler per 200 SF
max spacing between heads
15 ft for the 225 SF and max distance from a wall being one-half the required spacing
minimum distance from a partition to the nearest sprinkler
4”
upright heads
sit above the printer pipe and are used where plumbing is exposed and ceilings are high and unfinished
sidewall heads
used for corridors and small rooms where a single row of sprinklers can provide adequate coverage; can be plumbed from the walls instead of from the ceiling
pendant head
located below the sprinkler pipe, has many variations
fully exposed head
a fully exposed below the ceiling head is one of the most common
recessed head
partially recessed above the ceiling with its deflector below the ceiling
flush head
has only its thermosensitive element below the ceiling
concealed head
has a smooth cover that is flush with the ceiling; the cover falls away and the sprinkler head activated when there’s a fire
standard residential sprinklers
fast response devices sensitive to both heat and smoldering
quick-response sprinklers
more sensitive to heat than standard sprinklers, so it takes time for the device to reach the temperature needed to open the sprinkler
early suppression fast response
spray water at high pressure and at a higher rate of flow than most sprinklers, and are for use in more hazardous locations; designed to extinguish the fire while it is small; spray more water, are more sensitive to heat, and produce large droplets that penetrate plumes of fire
quick response early suppression
similar to ESFR but have smaller orifices and are designed for light-hazard occupancies
extended coverage
cover a larger area per peak than most sprinklers, but they may also be used only in light-hazard occupancies and under smooth, flat ceilings
Standpipes
vertical pipes to which fire hoses can be connected; they run the height of a building and provide water outlets at each floor; located within stairways or within vestibules
Class I
dry-standpipe system that is not directly connected to a water supply and is equipped with 2 ½” outlets for use by fire department personnel; required in non-sprinklered Group A buildings with occupant loads greater than 1000 persons, in covered and open mall buildings, in underground buildings, and on stages with areas greater than 1000 SF
Class II
wet-standpipe system directly connected to a water supply and equipped with 1 ½” outlets and hoses intended for use by building occupants
Class III
a combination system directly connected to a water supply and equipped with both 1 ½” and 2 ½” outlets; required in all buildings where the floor level of the highest story is more than 30’ above the lowest level of fire department vehicle access
Fire extinguisher, Class A
ordinary combustibles such as pepper, wood, and cloth; extinguishers contain water or water-based agents
Fire Extinguisher, Class B
flammable liquids such as gasoline, solvents, and paints; extinguishers use chemicals like carbon dioxide, foam, and halogenated agents to smother flames
Fire Extinguisher, Class C
electrical equipment; extinguishers contain nonconductive agents
Fire Extinguisher, Class D
combustible metals; extinguishers use dry powder extinguishing agents that absorb heat and smother the flames, such as sodium chloride or graphite
halogenated gases/halons
can be used to quickly extinguish a fire by chemically interfering with combustion; CFCs and HCFC
intumescent materials
respond to fire by expanding rapidly, insulating the surface they protect and filling gaps to prevent the passage of fire, heat, and smoke
candlepower distribution curve
graphically shows how light is delivered to a space; shows how much light is output at every angle from the luminaire
direct lighting
focuses 90-100% of its light output downward on the task; ex. Recessed fluorescent luminaire
semi-direct lighting
casts 60-90% of its light down and the other 10-40% toward the ceiling; surface mounted or suspended
direct-indirect lighting
provides equal amounts of ligh up and down
general diffuse lighting
provides 40-60% downward and the rest upward
semi-indirect lighting
provides 10-40% downward and the rest upwards
Indirect lighting throw
throws 90-100% of its light up towards a reflective ceiling to illuminate the room by reflection, no more than 10% is directed downward
task-ambient lighting
general background level of illumination is provided and separate light fixtures are available for increasing the light levels at individual workstations
Surface mounted fixtures
attached directly to the finished surface of the ceiling, directing all or most of the light into the room
recessed fixtures
used in both residential and commercial construction and include a variety of types of fixtures that use incandescent, fluorescent, and LED lamps
suspended fixtures
dropped below the level of the ceiling
wall-mounted luminaires
provide indirect, direct-indirect, or direct lighting
furniture-mounted lighting
built into the furniture for task illumination
spectral energy distribution
measure of the energy output at different wavelengths, or colors
color temperature
the temperature in kelvins to which a black body radiate or would have to be heated to produce light of the same dominant color
lower color temperatures vs higher color temperatures
lower color temperatures are warmer, higher color temperatures are cooler
color rendering index (CRI)
a measure of how closely the perceived colors of an object illuminated with a test light source match the colors of the object when it is illuminated with daylight of the same color temperature
maximum CRI rating
is 100; a light source with a rating of 85 or more is excellent
Illumination calculation for sources that are perpendicular to the light source
the illumination can be found with the formula
E=I/d(squared)
E is illumination (in for-candles), I is candlepower (in candles), and d is distance from the source to the surface (in feet)
Illumination calculation for sources that are not perpendicular to the light source
the formula is E=Icos0/d(squared)
0 equals the angle from the vertical
zonal cavity method
takes into account lime output of the lamps, number of lamps in each luminaire, portion of the light that reaches the work surface, and the amount of light lost due to various factors
coefficient of utilization
the efficiency of a luminaire in a particular space; between 0 and 1.0; the fraction of the total light from a luminaire that reaches the work surface
light loss factor
the amount of light from the lamp that is lost; between 0 and 1.0; the fraction of the total light from a luminaire that is lost due to a number of factors, including lamp lumen depreciation (LLD)
lamp lumen depreciation
light losts due to the age of the lamp
luminaire dirt depression
light loss dues to accumulated dirt
the formula to calculate the number of luminaires needed in a room to maintain a given illumination
N(luminaires)=EA/N(Lamps)N(lumens)(CU)(LLF)
E is the desired level of illumination in foot candles, A is the area of the room in square feet, N(lamps) is the number of lamps per luminaire, N(Lumens) is the number of lumens per lamp
isolux chart/ isofootcandle chart
a diagram showing lines of equal illumination produced by specific luminaire from a particular manufacturer
luminaire efficacy rating (LER)/luminous efficacy/efficacy
the ratio of the luminaire’s light output to its input power, typically expressed in lumens per watt; measures how efficiently a particular luminaire can produce visible light from electricity
LER calculation
LER = (EFF)(TLL)(BF)/W
EFF is the luminaire’s efficiency expressed as a two-place decimal fraction; a measure based on photometric testing of how efficiently the luminaire distributes light
TLL: the total lamp lumen; the number of lamps multiplied by the rated lumens output of each lamp
BF: ballast factor; expresses as a two-place decimal fraction
W: total power input expressed in watts
when comparing one luminaire with another
only similar types should be compared
LER applies to five different types of fluorescent lights
fluorescent lenses FL
fluorescent parabolic FP
fluorescent wraparound FW
Fluorescent industrial FI
fluorescent strip lights FS
International Energy Conservation Code
Standard 90.1 Energy Standard for Building Except Low-Rise Residential Buildings
Sets requirements for switching and other lighting controls, limits the total amount of power that can be used for lighting
comply with the requirements of Standard 90.1 by one of the following methods
Building area method
Space-by-space method
Energy cost budget method
Building area method
limits the total power used in a building by giving a maximum allowable power in watts per square foot of building area, based on the building type (lighting power density)
lighting power density
the maximum previously mentioned; varies with the types of facility
Lighting power allowance (LPA)
If there are different area types in the building, the area of each type is multiplied by the appropriate LPD to get the LPA
Space-by-space method
Assigns LPDs to common space types
The designer must determine the gross area of each space type in the building and multiply each area by the allowable wattage per square foot
The LPAs for all areas are added to arrive at a total LPD for the building
Energy cost budget method
Used to determine the energy cost budget for a specific building design
The budget is calculated by means of a computer simulation of hourly energy use over the course of a year by use of appropriate climatic data, approved envelope design, comparisons to a baseline building, and other aspects as defined in Standard 90.1
LPAs are only one aspect of the building’s total energy use; the designer can make trade-offs between energy needs for lighting and energy needs for other building systems
Lighting system tuning
Adjustment of the lighting installation after construction is complete
During tuning, lamps are replaced with lower or higher wattage units, adjustable luminaries are aimed for their optimal positions, ballasts are adjusted for maximum efficiency, and switches are replaced with dimmer controls or time-out units
in the event of a power failure
sufficient lighting must be available to safely evacuate building occupants
emergency and standby power are required to provide electricity for
-emergency egress illumination
-exit signs
-smoke control systems
-horizontal sliding doors
-means of egress elevators
in the event of a power failure, the emergency power must provide illumination to
-exit access corridors and aisles in rooms and spaces required to have 2 or more exits
-exit access corridors and exit stairways in buildings required to have 2 or more exits
-interior exit discharge elements when permitted, such as building lobbies where 50% of the exit capacity may egress through the ground-floor lobby
means of egress illumination level must be a minimum of
1 fc at the floor level and maintained for 90 minutes at least
Distance in an exit access corridor to an exit sign
No more than 100’
self-luminous exit signs
glow-in-the-dark; don’t need external power of batteries
photoluminescent exit signs
charged with energy absorbed from the ambient lighting during normal building operation
floor-level exit signs must by provided where
in Group R-1 occupancies
Communication Systems
include telephone systems, intercom systems, paging and sound systems, television, closed circuit television (CCTV), and computer systems, as well as local area networks (LANs) that allow the sharing of data on several computers within one building or in a complex of buildings
terminal room/equipment room
where the main telephone line connects
riser shafts
located near the core and connect telephone equipment rooms on each floor; telephone lines are split into these riser cables
riser closets/ apparatus closets
riser shafts provide space for cabling to serve each floor in these closets
If a building has a Building Automation System, then
a separate space is needed for the control center
BAS usually contains
controls for HVAC, energy management, lighting, life safety, security, and elevator operation
control center usually located
near the mechanical service rooms in the basement or main floor of the building
intrusion detection devices can be categorized into 3 types
-perimeter protection
-area or room protection
-object protection
perimeter protection
secure the entry points including doors, windows, skylights, and ducts, tunnels, and other service entrances
Perimeter protection devices
-magnetic contacts
-glass break detectors
-window screens
-photoelectric cells
area or room protection
detect when someone passed within the device’s field of coverage; can warn of unauthorized entry when perimeter sensors have not been activated
area or room protection devices
-photoelectric beams
-infrared detectors
-audio detectors
-pressure sensors
-ultrasonic detectors
-microwave detectors
object protection
used to sense movement or tampering with individual objects such as safes, artwork, file cabinets, and other equipment
object protection devices
-capacitance proximity detectors
-vibration detectors
-infrared motion detectors
Access Control
access control devices restrict access to secure areas
Access control devices
-mechanical lock
-high-security locksets
-electronic locks
—card readers
—Numbered keypads
—biometric device
5 basic types of fire detection devices
-ionization detector
-gas-sensing detector
-photoelectric devices
-flame detectors
-rise-of-temperature detectors
ionization detector
responds to combustion-ionized particles rather than to smoke; detects particles from a smoldering fire before it bursts into flames; early warning detectors
gas-sensing detector
detects combustion gases that are not normal present in the air; often used in combination with ionization detectors so that both gases and particulate matter can be sensed; early warning detectors
photoelectric devices
detect the next stage of a developing fire; contains a light beam that is obscured by smoke; useful where potential fires may produce a great deal of smoke before bursting into flames; variations are projected beam smoke detectors, scattered-light photoelectric detectors, and laser beam detectors
flame detectors
respond to infrared or ultraviolet radiation given off by flames; not early; triggered by final heat stage
rise-of-temperature detectors
sense the presence of heat and can be set to trip an alarm when a particular temperature is reached in a room; not early; triggered by final heat stage
Required types and locations of fire detection and alarms can be found in
The building code
3 ways to control sound within a space
-reducing the level of the sound source
-modifying the absorption in the space
-introducing nonintrusive background sound to mask the unwanted sound
reducing the level of the sound source
-not always possible, sometimes the sound is people in the room or a piece of machinery that needs to stay
-if the sound is coming from outside the room, the sound insulation can be improved
modifying the absorption in the space
-adding absorptive materials can achieve some sound reduction
-when the room has hard, reflecting surfaces
introducing nonintrusive background sound to mask the unwanted sound
-Desirable
-can reduce the sounds coming through a wall at the right STC rating
-random background noise is not reliable, use white noise, random noise, or acoustical perfume
room noise can be reduced by
adding absorption in tha space with acoustic panels or upholstered walls, effective only for higher frequencies and speech
low frequency control requires thicker partitions or more space for detailing
-panel resonator/ bass trap: an open box mounted on the face of a wall, or constructed as a part of a wall assembly
-cavity resonator/Helmholtz resonator: consists of a large air space with a small opening; common version is a special concrete block wall with narrow slits in the units
the higher the STC rating
the better the barrier is in reducing transmitted sound
Control of Sound Transmission
gaps must be sealed, edges must be caulked, penetrations should be avoided or if necessary, not rigidly connected to the barrier, electrical outlets should not be back to back; doors and windows should be avoided or specially constructed to reduce sound transmittance
Speech Privacy
conversations may be heard by others as unintelligible background sound
2 measures are used to evaluate open office acoustics
-articulation class AC
-articulation index AI
articulation class AC
replaced noise isolation class; gives a rating of system component performance and does not account for masking sound
articulation index AI
replaced speech privacy potential; measures the performance of all the elements of a particular configuration working together: ceiling absorption, space dividers, furniture, light fixtures, partitions, background masking systems, and HVAC systems; used to objectively test speech privacy of open office spaces, either in the actual space or in a lab mock-up of the space; used to compare the relative privacy between pairs of workstations or areas, to evaluation how changes in open office components affect speech privacy, and to measure speech privacy objectively for correlation with subjective responses
-rating between 0 and 1; 0 is complete privacy and 1 is no privacy at all
confidential speech privacy
exists when speech cannot be understood, AI is at or below 0.05
normal speech privacy
concentrated effort is needed to understand intruding speech; AI is between 0.05 and 0.20
AI above 0.20
speech is understood
AI above 0.30
privacy does not exist
AI and AC used for
open offices
speech interference level SIL
in decibels, the average of the sound pressure levels a(above a reference pressure level) of the interfering noise in the four one-octave bands centered on the frequencies of 500, 1000, 2000, and 4000 Hz; a useful measure of the background noise on spoken communications
the ceiling must be highly absorptive
create a ‘clear sky’ condition so that sounds are not reflected from their source to other parts of the environment
there must be space dividers that reduce the transmission of sound from one space to the adjacent space
to minimize sound reflections, each divider should consist of absorptive surfaces places over a solid liner (septum)
other surfaces such as the floor, furniture, windows, and light fixtures must be designed or arranged to minimize sound reflections
a window, for example, can provide a clear path for reflected noise around a portion height partition
if possible, activities should be distanced from each other to take advantage of the normal attenuation of sound with distance
there must be a properly designed background masking system
if the right number of sound absorbing surfaces is provided, the surfaces will absorb all sounds in the space, not just the unwanted sounds; background sound must then be reintroduced to maintain the right balance between speech sound and the background noise; referrred to as the signal-to-noise ration; speech privacy will be compromised if the signal-to-noise ration is too great, as a result of either load talking or minimal background noise
impact noise
the sound resulting from direct contact of an object with a sound barrier; can occur on any surface, but occurs most often on a floor and ceiling assembly, where ice can be caused by footfalls, shuffled furniture, and dropped objects
impact insulation class IIC
a numerical rating of a building floor’s effects on sound performance; those impact noise is quantified
the higher the IIC rating
the netter the floor reduces impact sounds in the test frequency range
IIC value of a floor can be increased by
-adding carpet
-providing a resilient suspended ceiling below
-floating a finished floor on resilient pads over the structural floor
-providing sound-absorbing material in the air space between the floor and the finished ceiling
mechanical noise
similar to impact noise in that the cause is due to direct contact with a building element; occurs when a vibrating device is in continuous direct contact with the building structure
mech noise can be transmitted by
-rigidly attached equipment can vibrate the building structure or pipers, which is turn radiate sound into occupied spaces
-the airborne noise of equipment can be transmitted through walls and floors to occupied spaces
-noise can be transmitted through ductwork
-the movement of air or water through ducts and pipes can cause undesirable noise
Mech noise can be controlled by
-mech equipment should be mounted on springs or resilient pads (isolators)
-connections between equipment and ducts and pipes should be made with flexible connectors
-where noise control is integral, ducts should be lined or provided with mufflers
-where possible, noise-producing equipment should be located away from quiet, occupied spaces
-walls, ceilings, and floors of mechanical rooms should be designed to lessen airborne noise
-mech and plumbing systems should be designed to minimize high-velocity flow and sudden changes in fluid velocity
reflection
the return of sound waves from a surface
-if the dimension of a surface is at least 4 times the wavelength of a sound striking it, the angle of incidence will equal the angle of reflection
-can be useful for amplifying sound in lecture rooms and concert halls and for directing sound where it is wanted
-reflection can create an echo if it delivers sound to the listener fractions of a second before the original sound makes it to the listener
diffusion
the random distribution of sound from a surface; occurs when the depth of the surface dimensions equals the wavelength of the sound striking it
diffraction
the bending of sound waves around an object or through an opening; explains why sounds can be heard around corners and why even small holes in partitions allow so much sound to be heard
plan similar use areas next to each other
use buffer spaces such as closets and hallways to separate noise producing spaces whenever possible
locate noise-producing areas such as mechanical rooms, laundries, and playrooms away from quiet areas
stagger the locations of doorways in halls and other areas to avoid giving a straight-line path for noise
locate operable windows as far from each other as possible
if possible, locate furniture and other potential noise-producing objects away from walls between spaces
to reduce sound transmission between 2 rooms, minimize the area of the common wall
avoid room shapes that reflect or focus sound; barrel vaults and circular rooms
avoid giving small rooms parallel-facing walls with hard surfaces
R-Value
Resistance to heat flow
Inverse of U-Factor (coefficient of transmission)
Transmission
Transmission= U x Area x dT
Total heat loss
Transmission + infiltration + ventilation
Degree day baseline
65
Doesn’t count when above
Average of high and low when it’s below
Opposite for cooling degree days
Overall heat loss for a typical year
U x A x 24 x HDD
Dead loads
vertical loads due to the weight of a building and any permanent equipment.
-include beams, exterior and interior walls, floors, and mechanical equipment
Live loads
those imposed on a building by the building’s particular use and occupancy and are generally considered movable or temporary
-Includes people, furniture, and movable equipment
Height of the wind above the ground
-wind velocity is lower near the ground due to friction, and increases with height
-wind speed values are taken at a standard height of 33’
Wind pressure
-positive pressure on the windward side of the building
-negative pressure on the leeward side and roof
-greater wind pressure at building corners, overhangs, parapets, and other projections
Building drift
the distance a building moves from side to side in the wind
-maximum drift should not exceed 1/500 of the height of the building
dynamic structural analysis
required for tall buildings or structures with complex shaped or unusual conditions
dynamic load
when a load is applied suddenly or changes rapidly
-cars moving in a garage, elevators traveling, helicopter landing on the roof
Fundamental period
the time it takes the structure to complete one full oscillation, such as swing from side to side in a tall building, or one up-and-down bounce of a floor
Impact load
when a force is only applied suddenly
coefficient of expansion
how much a material expands or contracts
statics
the branch of mechanics that deals with bodies in a state of equilibrium
equilibrium
exists when the resultant of any number of forces acting on a body is zero
3 fundamental principles of equilibrium apply to buildings
-the sum of all vertical forces acting on a body must equal zero
-the sum of all horizontal forces acting on a body must equal zero
-the sum of all moments acting on a body must equal zero
Vector quantity
a force which has both direction and magnitude
-direction shown by using a line with an arrowhead
-magnitude shows by establishing a convenient scale
collinear forces
those whose vectors lie along the same straight line; structural members subjected to collinear forces such as tension or compression are said to be two-force members
concurrent forces
those whose lines of action meet at a common point
nonconcurrent forces
have lines of action that do not pass through a common point
coplanar forces
forces whose lines of action all lie within the same plane; noncoplanar forces do not lie within the same place
stress
the internal resistance to an external force
three basic types of stress
-tension: stress in which the particles of the member tend to pull apart under load
-compression: stress in which the particles of the member are pushed together and the member tends to shorten
-shear: stress in which the particles of a member slide past each other
moment
the tendency of a force to cause rotation about a point
Positive moment
if a force tends to cause a clockwise rotation
Negative moment
if a force tends to cause a counterclockwise rotation
center of gravity
the point in a solid body at which the mass of the body can be considered concentrated
Centroid
the point on a plane surface that corresponds to the center of gravity
static moment
used to find the centroid of unsymmetrical areas
moment of inertia
a measure of the bending stiffness of a structural member’s cross-sectional shape
resultant
the single force from the combination of 2 or more concurrent forces, such that the one force produces the same effect on a body as the concurrent forces
free-body diagram
an extracted portion of the strucutre with forces acting on them represented as force vectors; the principles of equilibrium can be applied
required size of both wall and independent column footings
found by dividing the total load on the footing by the load-carrying capacity of the soil
