Building Construction Flashcards
Construction types
TYPE I- FIRE -RESISTIVE
TYPE II- PROTECTED NONCOMBUSTIBLE OR NON COMBUSTIBLE
TYPE III- EXTERIOR PROTECTED ( MASONARY OR ORDINARY)
TYPE IV- HEAVY TIMBER
TYPE V - WOOD FRAME
Area of refuge
Not required in sprinkler buildings
Must be equipped with 2 way communication
Green design
Primary hazard of green design is a tendency of components to a crease to combustibility of the overall building They have smaller dimensions in are more likely to fail under fire and fire suppression
Existing infrastructure
Primary concern is the water quantity needed for fire protection systems flow rate
Heat transfer
2 methods convection and thermal radiation
The 3rd Method of transfer conduction is not usually considered a factor in spreading fire between buildings
Convection, thermal radiation definitions
Convection involves the transfer of heat energy through the movement of hot smoke and fire gasses
Thermal radiation is the transfer of heat energy through space by electro magnetic waves
Higher temps move to lower temps
Exposure facts
Fire temperature is one factor in determining whether a fire will progress to an exposure the flames height in with are also relevant
3 levels of exposures
Light, moderate, or severe the levels are based on the fire load in the flame spread rating of the wall and ceiling finishes of the burning building
3 primary strategies in a fire incident
Offensive, defensive, transitional
Building construction designated by 3 digit number code
1st digit is the fire resistance rating in hours of exterior bearing walls
2nd digit fire resistant rating of structural frames or columns and girders that support loads of more than one floor
3rd digit fire resistance rating of the floor construction
Fire resistive
Fire resistance construction is classified by the process of non combustible structural components that have fire resistance readings within a specified range
Type 1non combustible materials
Most commonly constructed using a protected steel frame or reinforce concrete
Unprotected steel has no fire resistance it must be protected by insulating material
Type one combustible materials
Limited use of combustible materials are allowed in type one
Roof Coverings, Interior floor finishes, anterior wall finishes and trims, doors and door frames, window sashes and frames, platforms, nailing in furring strips, light transmitting plastics, foam plastics subject to restrictions
Type 2 construction protected non combustible or non combustible man
Steel concrete black glass and aluminum can mean use with limited structural role building codes also allow the use of combustible materials and take to construction for application similar to those in type one construction
Type 2 roof coverings
Some building codes containing a provision to omit the fire resistive rating for a roof construction for some occupancy types when the roof is located at more than 20’ above the floor
Type 2 a protected structures
Requires that structural components have One hour fire resistance
Type ll-B unprotected
Allows structural components to remain unprotected in unprotected non combustible construction the major structural components have no fire resistance.
Unprotected steel is the most calming characteristics of unprotected non combustible construction
Type 3 construction ordinary
Typically constructed with exterior walls of masonary
Nfpa Type lll 2-0-0 Unprotected steel is sometimes used to support combustible members
Hazards of type lll construction
Is conceal spaces created between floor and ceiling Joists
Conceal species in type 3 construction must contain appropriate fire stops
Type lv heavy timber
Sometimes called mill construction exterior walls are normally of masonary construction in the interior structural components are combustible
Zeal species are not permitted between structural components and type 4 construction
Type 4 construction the beams columns floors and roofs are made of solid or laminated wood with dimensions greater than in type 3 construction
Type 4 construction requirements
Min dimension of 6x10 inch for floor construction
Hazard of a type 4 construction
Primary fire hazard associated with type 4 construction is the relatively large amount of fuel present and structural supports in addition the interior of the building may have traces of oils in residues from previous industrial use
Type 5 wood frame
O major structural components are permitted to be of combustible construction
Hazards of type 5 construction
Hazards of type 5 construction is the presence of extensive conceal void these conceal spaces provide avenues for extension of fire within a building
Fire load
Fire load is the total quantity of combustible material in a compartment
Fire resistant describes what properties of material
Combustibility
Thermo conductivity
Chemical composition
Density
Dimensions
Fire resistance indicates the ability of a structural assembly to maintain its load bearing capacity and structural integrity under fire conditions
Laboratory testing
The most common method used to determine fire resistant
Laboratory fail requirements
failure to support in applied Load
Temperature increase on the unexposed side of a wall for roof assembly Of 250ﾟ Above ambient temperature
Passage of heat or flame through this sembly sufficient to ignite cotton waste
Access temperature on steel numbers
What ways are tests subjects for fire resistant ratings Expressed
15 minutes, 30 minutes, 45 minutes, 1 hour and a 1 1/2 hours 3 hours 4 hours the number is rounded down to the nearest interval
E 119 test
Only standardized test method currently universally accepted by building codes
The standard task evaluates the ability of structural assemblies to carry a structural load in to act as A fire barrier
Reactions R Definitions
The forces within a structural support system that resist applied loads are referred to as
Gravity
Is the most common load imposed on a structure via the weight of the structure’s components contents in any occupancy activity
Types of stresses
Tension- pulls the material apart
Compression- Squeezes the material
Shear- Slides one plane of a material pass in adjacent plane
Example concrete has high compressive strength but low tensile strength
Stress is caused by external load Alignments
Axial load
Eccentric load
Torsional load
Failure due to stress may include visible indicators such as cracking, crumbling, bending ,and breaking
Static loads
Static loads are steady or are applied gradually
Dynamic loads definition…………..
Dynamic loads could be when, moving vehicles karma earthquakes, vibration, fallen objects, energy or meeting its work
Involve motion in are capable of delivering energy greatly in excess of the weight of the object involved
Water loads
This Load may be dynamic as water flow or static as accumulated water.
Example stream discharge in 250 gallons per minute can impact a target with 2080 pounds of water per minute
Water loads
In high rise buildings accumulated water
DE watering operations will be necessary because water at a depth of 3” adds a static load of 21 pounds per square foot
What does the kinetic energy Air manifest as?
Wind
Wind loads
Direct Pressure straight line winds apply force to a surface
Drag
Negative -pressure when may produce a suction effect on the downward side of the building resulting in outward pressure
Rocking
Vibration
Clean off- When may dislodge or move objects from a building surface
When designing buildings what is the primary consideration?
When designing buildings to withstand when forces direct pressure is used as the primary consideration
Earthquakes seismic activity
As tectonic plates along a fault line or zone move or slip they produce vibrations
50 year period a typical expected lifespan of a building
Seismic load types
Lateral loads that create horizontal motion are the most significant force generated by an earthquake
Torsional loads are applied to a Structural member that is twisted by seismic motion
Resonantis seismic waves affect some buildings differently than others due to the resonate of the earthquake and each building’s features
Accommodations for sizement forces
Expansion joints
Dampening mechanisms
Base isolation
Dampening mechanism
Absorbs resonant energy For as the structure begins to move they are typically installed at the connections between columns and beams
Base isolation
Isolates the building from the horizontal movement of the Earth’s surface
Shear systems - elastomeric bearings placed in a layer between the building in the foundation the bearings change the fundamental resonance of the building.
Sliding systems- Special plates that slide on each other to isolate the building from horizontal shear force this system is a less common method of building isolation
Structural stiffening accommodations
Sheer walls in cross bracing for effective against ground motions with a relatively long slow vibrational.
Redundant structural members support the entire system making collapse less likely to occur
Soil pressure load
So I’ll exerts a lateral load pressure against a foundation this load must be evaluated in the design process
Structural accommodations for loads
A bean is a structural member that carries loads perpendicular to its longitudinal dimension
Types of beams
Simply supported beams supported beneath both ends and free to rotate
Restrained beams- Rigidly supported at each end under fire conditions a rigidly supported beam may retain its load bearing ability longer than a simply supported beam because the end restraints provide more resistance to the applied stresses
Cantalever beans supported at 1 end
Overhanging beams
Continuous beams may have several vertical supports the whole length
Fact about Beams
The top Flange of the beam carries compressive stresses
The bottom flange of the beam carries tensile stresses
Columns
Are structural members designed to support in axial load
The stresses created within D column is primarily compressive
Tall thin columns field by buckling short squat Columns Fail by crushing
Facts about arches
Curved structural member with primarily compressive interior stresses
R choose are used to carry loads across a distance
Trusses
R freyne structural units made up of group of triangles in one plane
the top and bottom members of a truss are called chords
Space frames
Our 3 dimensional trust structures they offer the advantage of to dimension trusses and terms of economic use of material
Load bearing walls
Low barren walls are commonly placed at the exterior of a structure but they may also include internal walls
load bearing walls carry compressive loads and provide lateral support to the structure along the length of the wall
Rigid frame structural system
Characterize by columns and beams reinforced to transmit the bending stress through the joint
Rigid frame buildings are often single story in height with a gabled roof
Membrane structures
Building codes typically a dress membrane structures with a life of a 180 days or more while fire codes addressed those used for less than 180 days
Advantages of membrane structures
Fabric weighs less than other roof systems about 2 pounds per square foot
Membrane structures can be erected in less time
Fabrics can flex and absorb some of the stresses caused by seismic and wind forces
Shell structures
Are often constructed with concrete in regular geometric shapes such as cones domes barrel vaults and folded plates
Most commonly constructed of concrete
Convenience stairs
Stairs that are not part of the means of I grass typically they are stairs that are open and connect only 2 levels per cold limitations
Straight run stairs definition
Street run stairs extend in one direction for their entire length
Return stairs definition
Have an intermediate landing between floors and reverse direction at that point
This type of steer design is common in modern construction
Scissor stairs
Are 2 separate sets of stairs constructed in a common shaft
The modern design arrangement for scissor stairs allows for in grass and negress that each floor landing this feature is used to provide additional exit capacity
Circular stairs
Only serving 2 levels
The minimum with of the run is usually 10” The small radius of the full circle is greater than or = twice the widest part of the stair tread
Spiral stairs
Consist of a series of steps spiraling around a single column to fit in a very small space
Sparrow stairs are allowed as part of the means of egress only within residences
Folding stairs definition
They are actually latter’s used to provide access to an attic space that does not have a perminent access stair
Firefighter should be aware that Springs in folding stairs lose tension rapidly when exposed to heat in the stair assembly may swing down into the structure during fire it can also provide a vertical path for fire and smoke spread
Smoke proof stair enclosures
Building codes require a minimum of one smoke proofs their enclosure for stares serve and buildings 5 stories or higher
Protection for stairs serving floor levels more than 30’ below the level of exit discharge also requires protection
Active versus passive fire protection
Active fire protection- uses moving mechanical or electric parts that work as a system in require a power source for operation Building systems may include automatic sprinkler systems or fire alarms
Passive fire protection- Does not require any system activate tion or movement pacifier protection relies on building construction and materials to contain fire or products of combustion examples fire walls or stair enclosures
Open stairs restriction
Building codes typically allow the use of open stairs and buildings only when they connect no more than 2 adjacent floors above the basement level
Mechanical conveyor systems
Compare systems penetrate fire barriers they’re protected by fire doors shutters water spray fire suppression systems
Incomplete door or shudder closure is a primary safety hazard at a conveyor penetration doing a fire
Safeguards against that automatic stop controls breaks in the conveyor multiple layers of doors are shutters
Moving stairs
Escalator speeds are standardize at a 100’ per minute older escalated usually operate at speeds of either 90 or a 120’ per minute
Vertical penetrations for escalators serving more than 2 floors must be protected the most common protection is to use closely spaced sprinklers and draft stops around the opening
Requirements for vertical penetration in moving stairways
Combine these 2 features may be arranged as an 18” deep draught stop with a row of automatic sprinklers on all sides outside the draft stop
Elevators
Search 2 or more a levels or landings
Enclose hoisting and lowering mechanisms
Provides access to above or below grade stories
Uses a car or platform that moves along guide rails
Types of elevators
Passenger elevators
Freight elevators
Service elevators
2 most common types of power used in elevators are hydraulic and electric
Hydraulic elevators
Uses hydraulic fluid to raise and lower the car
The upper limit for the hydraulic elevator is 6 stories
Electric elevators
Drum elevators are obsolete only in older buildings
Traction elevators are the most common type of elevator and buildings over 6 tours traction elevators are fast and do not have the height limitations of either hydraulic or drum type elevator
Power supply is 500 Volts
Elevator hoistways
Single, multiple, blind
Elevator Hoist ways Are required to be fire rated as assembly with a 1 or 2 hour rating
Codes require venting at the top of the hoistways
For more elevators must have a minimum of 2 separate hoist ways
Blind hoist ways
Are used for express elevators that served the upper elevator zones in a tall building
In a single car voice way is use access doors will be provided for rescue purposes generally these are spaced every 3 floors
Refuse in laundry chutes
Sprinklers are required at the top of the shute and in its termination room
Fans for HVAC
Duck detectors are typically provided for fins with a capacities exceeding 2000 ft³ per minute
To stop these systems under fire conditions and minimize unwanted smoke movement
Forced air systems
The force air system in a multi story building often includes vertical ducts and a mechanical Room with a few minor exceptions the codes require the HVac ducts to be enclosed in a fire rated
shaft and closure of one hour rating for buildings less than 4 stories in height and 2 hr rating for buildings 4 stories are greater
Manual smoke control
When a system has both automatic in manual keep ability the manual operation shall take priority over the automatic control
Smoke vents
Vent types?
Draft curtains may be used in conjunction with smoke vents to increase their effectiveness
The depth of a curtain board will vary but should not be less than 20% of the ceiling height curtain board should be space so that they are not farther apart than 8 times the ceiling height
Pressurize stairways
Types of pressurization systems
Single injection system uses a fan to supply air to us they’re well at a single point
Multiple injection systems you several discharge points along and air so supply shaft running parallel to the stairway from that supply fan
Electrical equipment
High voltage is defined as 600 V or high or low voltage equipment operates at less than 600 V
Transformers
Convert high voltage electricity from the electric utility service to an appropriate voltage for building systems
2 types of cooling methods for Transformers
Air cooled- Called dry Transformers used the surrounding air to cool the unit through fins
Oil cooled- Boyle film Transformers contained oil to conduct heat away from the core in also to electrically insulate internal components from our arcing
Code for oil cool Transformers?
When Transformers are inside codes required that the transformer rooms or vaults being closed in 3 hour rated construction if not protected by automatic sprinklers or one hour rated construction with sprinklers
Generators
Operational requirements for hospitals and other critical facilities may be up to 48 hours or longer
Few storage should be located separately exception is a dating located in the same Room or mounted directly on the generator fire codes typically limit the tank to 60 gallons for diesel fuel
Interior finishes definition
Includes the materials used for the expose face of the walls and ceilings of a building
Plaster, gypsum, wallboard, wood paneling, ceiling tiles, plastic, fiber board, wallcoverings
Exterior finishes classified as trim
Do not exceed 10% of the wall and ceiling area
Distributed through the space
Do not constitute a large continuous surface
Surface burning characteristics
Flame spread over a specific material can be measured and predicted in degrees By evaluating composition thickness, ventilation, shape and size of a compartment, finish material on the ceiling or wall
Most significant factor that determines a fuels burn rate is the combination of the fuel and the available oxygen
Thin surface treatments
Building called usually exclude reference to surface treatments such as paint and wallpaper that are no thicker than 1/28th of an inch
Fire retarded Coatings
Intumescent coating
Mastix
Gas forming paints
Cementituous and mineral fiber coatings
Intumescent paints expand upon exposure to heat and create a thick puffy coating that insulates the wood surface from heat and excludes oxygen
Mastic- Form a thick non combustible coating over the surface of the wood
Fire retardant coatings hazards
Code officials do not accept fire return it treatments for perminent applications
Reasons coatings must be applied to specific rate of square feet per gallon and may require more than one coat
Only protects the coated surface not the untreated backside
A material to be fire retardant must be tested and listed for use in a fire resistive assembly
What is the standard tests used for measuring the surface burning characteristics of interior finish
Asthma e-84 uses the STEINER TUNNEL
Consists of a horizontal test furnace 25’ long 17.5” wide and 12” high and a 5000 BTU flame is produced in the tunnel
Flames spread rating
Interior finishes are tested to derive several measures of a materials flammability including the flames spread rating in the smoke developed rating
The higher the flame spread rating the more rapidly flame will spread
Flame spread ratings over 200 are not permitted in occupancies
Floor coverings
Worth the flame spread rating developed in the ASTM E84 test does not apply to floor coverings
When carpet is use as for a floor or ceiling finish the carpet must meet the same plane spread criteria as other wall and ceiling finishes
Smoke developed ratings
The smoke developed rating is a measure of the relative visual obscurity in an area because of the smoke generated by a burning material
Red oak is used as a standard testing material is a sign I smoke develop reading of 100 under test conditions of material with a smoke developed rating of 200 produces smoke that is twice as visually obscuring as red oak codes do not allow a combination of materials that exceed a maximum smoke developed rating of 450
Limitations of test findings
The large variety of combinations of products used in most occupants ys will not limit the exact match between test results in conditions in these occupancy
Test results should be use as benchmarks not guaranteed outcomes
Fire walls
Must have sufficient fire resistance and structural stability to serve as an absolute barrier to eat fire and structural collapse on either side of the wall
Freestanding walls
Are self supporting with respect to Eve word acle load
Freestanding fire walls are usually found in buildings of type 3 or 4 construction
Freestanding walls must be designed to resist a lateral load of a least 5 pounds per square foot
Parapet walls
Fire walls must extend beyond walls and roofs to prevent the radiant heat of flames on one side of the fire wall arming igniting adjacent surfaces continue into wall through the roof with a Parapet wall is sufficient separation
Parapet height above a combustible roof varies from 18 to 36”
Fire resistant ratings of fire walls
ICC allows fire walls with fire resistant radiance of 2, 3, 4 hours depending on occupancy
Historically fire walls were required to have 4 hours fire resistance
Fire partitions
interior walls that do not qualify as fire walls but are used to subdivide a floor or area of a building fire petitions are not required to extend continuously through a building usually erected from a floor to the underside of the floor above
For example partition wall and close in in exit corridor may have won our fire rating that can be reduced when sprinkler systems is in stalled
Enclosure and shaft walls
Enclosure walls are required to have a fire resistance rating of 1 to 2 hours stairwells in buildings 4 stories or lower a required to have a 1 hour rated enclosure buildings taller than 4 stories stairwells are required to have to a 2 hr rated enclosures
The purpose of enclosure walls is to block the vertical spread of fire through a building’s openings
Stairwells, stairwell exit passage ways, elevator shafts, pipe cheeses
What are the most common construction materials used for enclosure walls?
Gypsum board with steel or wood studs
Lath and plaster
Concrete block
Hello clay Tile enclosure walls
What is a curtain wall?
A style of wall designed to separate the interior environment from the exterior environment
Curtain walls are often non load bearing
9 fire resist of curtain walls frequently extend from the floor to the ceiling of one level
Fire door classifications
Fire doors are rated in increments of time from 20 minutes to 4 hours
the 1/2 hr and 1/3 doors a primarily used in smoke barriers in openings to corridors
Fire door rating system
Class a openings in fire wall
Class B openings in vertical shafts in openings into our raid it partitions
Class C openings between Rome’s in corridors having a fire resistance of one hour or less
Class D openings in exterior walls subject to severe fire exposure from the outside of a building
Class E openings in exterior walls subject to moderate or light exposure from the outside
Fire door requirements
Redundancy in the code for example a code may require( 2 )3 hour fire doors to protect an opening in a 4 hour Wall
Codes require 3 or 4 hour read it doors in fire walls of greater than 2 hour rating
Doors rated at 1.5 hours are normally required for 2 hour read it vertical enclosures
One our doors are used for 1 hour vertical shaft enclosures and exit enclosures
Types of fire doors
Should never be used in the path of egress
Rolling overhead door For closes under the force of gravity when a fusible link melts or a smoke detector releases the hold open device
Horizontal sliding doors are often found in older industrial buildings these doors are usually held open with the fusible link when the link is activated the door slides into position along the track either by gravity or by a force of a counterweight
Type of fire doors
Swinging fire doors commonly protects stairwell enclosures in corridors
swinging fire doors are available with ratings from 20 minutes to 3 hours
Special fire doors Include horizontally sliding accordion or folding doors Uses a motor and needs power
Horizontal sliding accordion doors are used where a fire rated partition is required
Glazing
Fire doors are the most time in application of fire read it glazing doors with ratings up to 3 hours can be equipped with glazing
N FPA 80 requires the each piece of glazing installed in a fire door include a listing mark that remains visible after installation
Test question on glazing
Fire doors with the reading of 1 to 3 hours can have glass panels up to 100 in² in area per door fire ratings of point 3/4 hour can have a total glass area consistent with their listing
Fire door testing
Criteria for doors is that they must remain securely in its frame during the flame test.
Some warping permitted
Intermitted passage of flames is permitted after the 1st 30 minutes of the test
2nd criteria door must remain in place when subjected to a whole stream immediately following the fire test. This part not tested on 1/3 rated doors
Marking for rated fire doors
Door type, hourly rating, identifying symbol of the testing laboratory
Marked with a label or plate on the top or on the hinge side of the door
Soil properties
For 2 strategies used to it assess soil our test pits and test borings
Test pits may reach a depth up to 8 ft the strata layers of the soil to be observed in measured
Test borings or use when a test pit may not reach deep enough it provides information on bearing capacity of the soil and the water table
Shallow foundations
The weight of one story of soil can equal 5 to 8 stories of a building dependent on the density of the soil and the construction features of the building
Deep foundations
* When a pier is design with a footing it is known as a belled pier
Piles are driven into the ground and support a load by transferring the load either through friction with their surrounding soil or through contact with rock or other stable soil Layer
Piers- Post in pier foundations are a system of upright post mounted to wed she concrete piers that chance for the weight of the structure to the ground
Foundation walls
Concrete in masonary brick or concrete block secured with mortar are the materials most commonly used for a foundation walls
Building settlement
Settlement -downward movement
Heaving - outward movement
Lateral displacement- Outward movement of
Symptoms of settlement include
Distorted building frame
Sloped floors
Cracked walls and glass
Improperly working doors and windows
Damage building utilities and systems
Shoring in underpinning
Shoring is frequently necessary to support the structure until underpinning can be put into place
Shoring is refers to temporary supports
Underpinning refers to perminent supports
Underpinning may be necessary if there is excessive settlement, increased load on a foundation, excavation on adjacent property, erosion of soul from under or around the foundation
Solid wood
Defects in Wood have a greatly reduce this comparison so the standard tensile strength of wood is considered about 700 psi
Structural lumber has 19% or less moisture is expressed in terms of specific gravity
Laminated wood
The butt joint is easy to produce but can not be used where tensile stresses will be transmitted
Scarf and finger joints can be used to transmit tensile stresses
Glulam beams
Research indicates that the heat of a fire has no effect on the adhesives that are used in contemporary glue Lam beams
GluLam beams are used frequently and heavy timber construction where greater length components are required
Parallel strand lumber
Is the strongest of the 3 seo products and can be used for a heavily loaded columns and will and long Spans
Thermo plastic
Composite lumber is would like product made from wood fiber and polyethylene or polyvinyl chloride ride PVC developed as an alternative to PT lumber
It is a combustible product with a flame spread rating of 80
Will melt like plastic
Draft stopping
The usual requirement is for the attic space to be subdivided into areas of 3000 ft²
Brick or stone veneer
Veneer must be tied to the wood frame wall at intervals of 16”
Under fire conditions the external layer of brick or stone veneer build and protects the wood frame from external exposure veneer adds little structural support
Ignition temperature
Materials with low Ignition temperatures are easier to ignite the materials with high Ignition temperatures
Pyrolysis Thermal decomposition of wood begins at a temperature of 392ﾟ
Ignition temperature depends on what?
Density of the wood
Size in form of the wood
Moisture content
Rate of heating
Nature of the heating source
Air supply
Pyrolysis fact
Pyrolysis and Ignition can occur at lower than normally required if the wood is subjected to a temperature higher than ambient but lower than Ignition temperature
Heat of combustion
The heat of combustion of a fuel is the total amount of thermal energy that can be released if the fuel is completely burned
It is measured in British thermal units BTU
Fire retardant treatment of wood
2 methods of fire retardant treatments are
surface coating- Reduces flame spread
Pressure impregnation- A first the whole component Permanent
Disadvantages and limitations of fire retardant treatments
Water soluble chemicals are not approved
Compliance with approved usage cannot be proven after application
A test question Fire retardant treatment reduces wood strength
what our fire retardant treatments Composed of?
Combination of inorganic or organic salts
Ammonium phosphate , ammonium sulfate, boric acid zinc chloride ,sodium dichromate, borax
Hygroscopic
The ability of a substance to absorb moisture from the air
When exposed to elevated temperatures plywood can absorb moisture and become brittle and crumbly
Ignition resistance construction requirements
Fire resistance roof covering to Protect against In embers
Exterior wall that is either non combustible or has a one hour fire resistant rating
Limitations on size of attic and under floor vents
Platform framing fact
Platform framing is more prone to shrinkage then balloon frame and because platform frame and makes use of more horizontal members in its frame then a balloon frame building Creating vertical movement
Kiln dried lumber minimize is affect
Heavy timber Features
Trusses or beams can use be used as roof supports
Exterior walls are non load bearing panels with exterior siding
A test question
Internal support columns are not less than 8 by 8” and the beams (except roof beams )are not less then 6 by 10”
Type 4 heavy timber construction
Has thicker dimensions
Does not allow combustible concealed spaces
Engineered wood systems
Primary safety limitation is the possibility of swift collapse under fire conditions especially if void species are not protected by a non combustible covering or sprinkler system
Masonary construction facts
The benefit of masonary components is their durability and resistance to whether fire and insects
The drawback to masonary construction is long term deterioration of mortar joints in the labor intensiveness of laying individual units by hand
Brick manufacture
Placing clay and moles
Slice bricks to desired size
Kiln Dried at temperatures of 2400ﾟF the process takes 40 to a 150 hrs
Concrete blocks
The most common is 8 by 8 by 16 Block
Concrete blocks
The most common is 8 by 8 by 16 Block
Mortar facts
The mortar joints are often the week is part of the wall
Compressive strengths ranging from 75PSI to 2500 psi
Fire resistance of masonary walls
A wall the has not been undermined or weaken is usually the last structure to fail in a wood joisted building
Fire rated concrete units can have a fire resistance of 2 to 4 hours or more
Construction of masonary walls
The weight that a wall can support will depend on the with of the wall and whether it is reinforced or non reinforced
None load bearing masonry walls
Test question
Masonary can be used for non load bearing curtain walls or partitions jipson block in lightweight concrete block are limited to use in non load bearing partition walls
Load bearing masonry walls
In a ordinary non reinforce load bearing wall the strength instability of the wall are derived from the weight of the masonary in horizontal bonding of each wythe of wall to other wall components
Load bearing wall fact
Was that provide structural support from multi story buildings must be greater in thickness because masonary units in the lower portions of a wall must support the dead load weight of the upper portions of the wall
Limitations of non reinforced masonary walls
Non-reinforced masonary walls are usually limited to a maximum height of 6 stories
Brick and concrete block construction
Test question
Masonary units are laid side-by-side in a horizontal layer known as a course
A stretcher course has bricks Placed end to end
A soldier course has bricks place vertically on end
A header course has bricks placed with the ends facing out
Reinforced masonary walls
Masonary wall that is reinforced with steel can have a reduced thickness
Walls can be constructed to a height of 10 stories or more with a wall thickness of only 12” when using reinforce masonary
Openings in masonary walls
Lintels- Are the most common method of supporting loads over openings in masonary walls
Corbelling is used to improve that aesthetics of an arch
Parapet wall
Extension of a masonary or steel wall the projects above the roof 1’ or more
Collapse of masonary construction
Test question
Collapse zones are typically 1.5 times the height of the building all around the building’s perimeter
Properties of steel and iron
Common structural steel has less than 3/10 of 1% carbon
Cast iron has a carbon content of 3 to 4%
The higher carbon content of cast iron makes the material hard but brittle
Basic properties of steel
The following elements add it to still will altered the composition of the material contribute increase specific attributions
Molybdenum- strength
VANADIUM- STRENGTH AND TOUGHNESS
MANGANESE - RESISTANCE OF STEEL TO ABRASIONS
Steel ductility
The lower the carbon content of steel results in a material that is duck tile that means it can be shaped by rolling when heated to 2200ﾟF
Steel facts
An unrestrained steel beam 20’ long can expand 1.4” pushing at lateral constraints
The deterioration of steel strength at elevated temperatures is the characteristic most significant to the fire service
Fire protection of steel
In older buildings the steel framework was encased in brick or ordinary concrete a steel column and cased in 3” of concrete with a salacious aggregate would have a fire resistance of 4 hours
Spray applied materials
Are efficient and and in expensive
The most commonly use SFR m’s are mineral fiber or expanded aggregate coding such as vermiculate perlite
Fire insulating materials
The applied fireproofing can vary from 7/8 of an inch to 1 7/8 of an inch to produce a fire resist of rating of 1 to 4 hours
Gypsum facts
Gypsum Includes approximately 20% in trapped water the water content enhances Gibson’s performance as a fire insulating material
The water turns to steam upon exposure to fire and then doing so absorbs the heat the process is known as calcination
Gypsum can be used to protect both columns and beams providing fire resistant ratings from 1 to 4 hours
Intumescent coatings
When heated the material will expand to 15 to 30 times its original size
It is applied as pain they haven’t applied thickness of point .03 to.4” which is less than the thickness of the spray applied materials
Membrane ceilings
Protects a steel floor or roof assembly the most common method is to use mineral tiles and a steel framework suspended by wires
The seal in materials act as a thermal barrier to protect the steel that supports the floor or ceiling above This will give a floor a fire rating of 1 to 3 hours
Steel columns (Slenderness ratio)
Slenderness ratio compares the unbraced length of a column to the shape in area of its cross-section the higher the numerical value of the slenderness ratio the more likely it is that buckling will occur and general columns used for structural support and buildings should not have a slenderness ratio greater than 120
Steel column fact
The slenderness ratio Is modified by the manner in which that ends are attached to the rest of the structure
Columns that are erected so they can not rotate at their ends have fewer tendencies to buckle then columns that are free to rotate
Floor systems in steel framed buildings
Open Web joist
A common floor design in steel frame buildings uses lightweight concrete with the minimum thickness of 2” supported by corrugated steel decking
steel beams
The steel joist are produced with depths of 6 to 12” and can be space 16 to 48” apart dependent on the span and the load to be supported
Code modifications
Fire resistance ratings may be eliminated for Roof construction located more than 20’ above the floor below for some occupancy
Allowance is also made for reduction in fire resistance when in automatic sprinkler system is Present
Collapse of steel structures
Test question
In gabled rigid frame structures the knee joint between the roof and the wall will be the strongest part of the frame and the last part to fail
The knee joint helps transfer the roof load to the vertical members
Test question
Steel connections both in the case of rigid connections used with beam in garter frames and heavy trusses frequently use a steel Web known as a gusset plate
The primary purpose of a gusset plate is to strengthen the connection and increase the steel mass at the connection decreasing the possibility of failure
Admixtures for concrete
Shale or clinker- Reduce the density of the concrete
Superplasticizer- Produce a mixture that flows more freely
Coloring- Add it for aesthetic or safety reasons such as indicating Buried electrical cables
Reinforced concrete
Concrete is strong in compression but weaker in tension. Rebar wire mash is added to overcome the tension
Pre stressing reinforcing
2 common methods of pre stressing concrete are pretensioning and post tensioning
Pre tensioned reinforcement concrete
Uses steel strands cables stretched between anchors producing a tensile force in the steel
Concrete is then placed around the steel strands in allowed to harden
Post tensioned reinforcement
Uses reinforcing steel cables that are not tensioned until after the concrete is hard and to a certain strength the forces that are produced in the post tension eing process remained locked in the steel for the life of the assembly
Collapse of pre stressed concrete
The systems using reinforcing cables in rods made of high strength steel that can yield at a temperature is low as 752ﾟF
Pre stressed concrete systems may be more vulnerable to failure than ordinary reinforce concrete
Water to cement ratio
The single most important factor in determining the ultimate strength of concrete is the water to cement ratio
Hardening of concrete
Is it chemical process known as hydration in which water combines with the particles of cement to form a Microscopic gel
Cures after 28 days
Temperature for curing of concrete
In the process of curing concrete must be maintained at the correct temperature of 50ﾟ and 70ﾟ
Slump test
Purpose of this test is to check the moisture content of a batch of concrete as indicated by the mount that the concrete’s saddles slumps after it is removed from the test mold
Fire resistance of concrete construction
Has a rating of 1 to 4 hours
Fire resistance is affecting by density, thickness, quality, supported load, depth of concrete cover over the reinforcing bars
Waffle construction
Slap in being concrete frame and features concrete beams run and in 2 directions is known as a 2 way slab construction
Waffle construction is use where spans are short and floor loadings are high this design provides a thicker slab while eliminating the weight of unnecessary Crane Creek in the bottom half of the slab
A pre cast concrete slabs for floor systems
Salad slabs are used for short spins a to approximately 30’
T slabs can be used for spans up to 120’
Tilt up construction
Is a common form of construction used with precast concrete
This dollar construction requires that the roof assembly maintain structural integrity value of the roof can result in failure of the wall from outward horizontal forces
Rebar facts
The most commonly size used is # 5 ( 0.625 inches)
Concrete beans
Are cast in the shape of tee. The wider area at the top of the T permits the concrete to support a greater load.
Stirrips- are Vertical reinforcing Bars that resist diagonal tension
Roofs and firefighting
Test question
Many Types of roof construction have concealed spaces between the ceiling and the roof deck making it difficult to determine the extent to which a fire has developed overhead
Pitched roofs
The pitch of a roof represents a major hazard to firefighters because the steepness of the roof results and the lack of secure footing
Low slope roofs 3/12
Med slope 4/12 to 12/12 which is a 45 degree angle
Churches or mansions can have 18/12 or greater too steep for FF
Types of pitched roofs
Test question
Gable roof- Consists of 2 inclined surfaces that meet at their high side to form a ridge
HIP ROOF- Slopes in 4 directions and has a degree of slope similar to the Gable roof.
GAMBREL ROOF- slope in 2 directions but there will be a break in the slope on each side. The space under a gambrel roof can be used as an attic or living space.
MANSARD ROOF- Has a break in the slope of the roof on all 4 sides
BUTTERFLY - Roof style that slopes in 2 directions to shed roofs that meet at their low point Center
MONITOR ROOF- Provides light and ventilation a race central section of the roof extends several feet above the surrounding roof surface Make a cupola.
SAWTOOTH ROOF- Commonly used in industrial buildings for light and ventilation vertical sections facing the North more constant daylight
Curved roof fact
Curved roofs are most frequently supported by arches in bowstring trusses
Conventional roof framing definition
Use incline members to support some types of pitch roofs that are built on site utilizing dimensional lumber
A common truss
Becoming trust is a range with all of the chords in diag’nal members in the same plane
Wood and steel trusses
FINK and PRATT trusses are the most common types used for pitched roofs
Roof deck materials
The corrugated steel range from 29 gauge the thinness to 12 gauge the thickness the overall depth is from 3/4 of an inch to 2”
Roof coverings factors
Expansion and contraction from rooftop temperatures that can range from over a 100ﾟF in this summer in the low 0ﾟ in the Winter must resist
Wear course( roofing )
The where course protects the roof from mechanical abrasion built up reus that use gravel as a where course are commonly known as tar and gravel roofs
it also increases the resistance of the roof to spread fire from adjacent buildings
Slate as a roofing material
1/16th of an inch to 1 1/2 inches life expectancy of a 150 years weighing 8 to 36 pounds per square foot
Roof covering test
Test question
Class a roof coverings are effective against severe fire exposure
Class B ru coverings are effective against a moderate fire exposure
Classy roof coverings are effective against a light fire exposure
Vegetation roof systems
Create a dead load on the roof dependent on the depth of the soil the dead load can vary from 20lb per square foot to a 150 pounds per square foot
Skylights limitations
Materials used for skylights can only be plastic wired glass or tempered glass
High rise construction type
Model building codes required 2 or 3 hour fire resistance for the structural frame of a high rise building
Dependent on the number of stories in occupancy ,2 hr fire resistance for floor construction
Fire command in a high rise building
Typically a fire command center is located on the 1st floor or level of fire department access
The Room has a minimum one hour Fire separation From the rest of the building
Emergency elevator use
Codes require a shunt trip where the elevator Heuss way or elevator Room is protected by automatic sprinklers this will shut down the power to the elevator before a sprinkler discharges water on the elevator equipment
Phase one elevator operation
Code contains provisions for the recall of all passenger elevators with a vertical travel greater than 25’ in the event of fire
Phase one operation automatically stops all the cars that serve the fire floor if there are movin away from their terminal floor the lobby It also causes the cars to return nonstop to the lobby
Phase one operation
The elevators cars emergency stop in floor selection buttons are rendered in operative so that the car occupants cannot stop the car anywhere but at the terminal floor
Phase 2 operation
Is designed to override the the recall feature to permit firefighters to use the elevators after they arrive on scene
In this phase a firefighter must insert a key in a 3 position switch to put it into fire service mode
The electric I safety which prevents the doors from closing if a person or smoke is in the doorway is disable during this operation
Limited access buildings
Constrict firefighter ability to quickly in efficiently ventilate the building as a result building codes generally required that these buildings be fully sprinkler
Upper floor should have emergency access openings on 2 or more sides in the upper floors
Underground building
May have occupancy areas 30’ or more lower then their primary exit
Smoke and fire considerations in a underground building
Greatest challenge in control and fires is difficulty in venting heat and smoke
Smoke proof enclosures are required for buildings with levels more than 30’ below the level of exit discharge
Max fire resistance is 4 hours
Special provisions
Underground portions of the buildings must be fire resistive construction where floor levels are more than 60’ below the level exit discharge separation of each level into to approximately equal size compartments may be required
Automatic sprinklers are required
Smoke exhaust system is required
Mall building configuration
Building codes require that mall walkways be a minimum of 20’ wide dispeace permits pedestrian travel and also the use of open storefronts
Mall construction
Code requires individual stores within the shopping mall to have one hour fire resistive separation from each other but they do not require that individual storefronts are separated from the mall itself
Smoke control systems in a mall
Codes do not require it for one story shopping malls however they are required in covered mall buildings with 3 or more stories
Atrium definition
Is a large vertical opening extending through 2 or more floors of a building that is not used for building services such as enclosed stairs elevators or building utilities
Code for Atriums
Test question
Some codes wave requirement for sprinklers when atriums or more than 55’ above the floor
Call requires for atriums include automatically sprinkler protection the building codes have a basic requirement that a atrium be enclosed with one hour fire rated construction or a combination of glass and automatic sprinklers
Areas of refuge
The typical smoke barrier consists of a minimum of one hour fire rated enclosure
Elevator lobbies in in close exit stair landings are logical location for areas of refuge
Must be provided with 2 way communication system connected to a constantly attended location
Rack storage
Can range from a total height of 12’ to an excess of a 100’ Isles nearer than 3.5’
Temporary fire protection systems
Stamp pipe risers must be extended a as construction progresses in a high rise building and lows rise building more than 3 stories
Building and fire codes require this nameplates be extended before the construction reaches 40’ above the lowest level of fire department access
The top hose outlet should be within one story of the uppermost level that has a secure floor
Fire extinguisher requirements at construction sites
Generally a ABC extinguisher a dresses majority of hazards at construction site
In APA to 41 requires the presence of A20B rated extinguisher door and roofing operations
Building renovating and remodeling hazards
The primary hazard unique to renovating in remodeling is did disturbance of hazardous substances such asbestos
Subsidence
Primary cause is removal of large amounts of underground water or oil over yours beneath built up areas this is usually gradual and fairly uniform when the cause is the removal of an underground liquid
Fire load vs. Structural load
Test question
A fire load may not directly translate into in equivalent structural load
Stresses
Test question
The total stresses within structural members must be lower than the failure point of the material for the structure to remain intact
A ratio of the failure point of the material to the maximum supportable design stress is added to the minimum required strength as a FACTOR OF SAFETY
Roof coverings that pass the required test procedures
Test question
Class A roof coverings are effective against a severe fire exposure
Class B roof coverings are effective against a moderate fire exposure
CLASS C roof coverings are effective against a light fire exposure
