Chapter 6 Building Construction Flashcards
Occupancy
refers to how a building is used, how many people are in there, helps determine hazards and situations encountered
Contents
amount of possible fuel in building
Types of construction materials
- Masonry
- Concrete
- Steel
- Glass
- Other metals- zinc, aluminum, copper
- Gypsum Board
- Wood
- Plastics
Key factors that affect the behavior of each construction material
- Combustibility- whether or not a material will burn
2. Thermal conductivity- Characteristic describes how readily a material will conduct heat
Steel elongate at what rate
1 inch per 10 ft at a rate of 1000 degrees
Masonry
stones, concrete blocks and brick are inherently fire resistive used to construct fire walls
Concrete
like masonry concrete is a naturally fire resistive material, does not burn or conduct well
Spalling
when steam expands it creates internal pressure that can cause sections of concrete to break off
Steel
the strongest building material in common use but is not fire resistive and conducts well. Strong in tension and compression used as structural frame work any signs of bending and sagging is a sign of structural collapse exit immediately
Other Metals
aluminum, copper and zinc used for windows doors, wiring and coating
Glass
used in windows, doors sky lights and sometimes walls. glass is non combustible
- ordinary glass breaks under heat
- Tempered glass is much stronger more difficult to break
- Laminated glass cracks and remains in place under heat.
- Glass blocks have limited strength but they can usually withstand fire.
- Wired glass is tempered glass with a metal wire mesh. this prevents the glass from breaking under heat used to prevent fire spread
Gypsum Board
also called dry wall, sheetrock, or plaster is commonly used to cover the interior walls and ceilings of residential living areas and commercial. limited combustibility. used as fire stop
Wood solid lumber
most commonly used material, is squared and cut into uniform lengths
Laminated wood
individual pieces of wood glued together. produce beams that are longer and stronger and manufactured curved beams
Wood Panels
are produced by glueing together thin sheets of wood. ex ply wood OSB
Wood Trusses don’t trust the truss
assemblies of pieces of wood or wood and metal combinations made to support roofs and floors limited material for heavy load
Wooden Beams
Efficient load bearing members assembled from individual wood components.
Rate at which wood ignites, burns and decomposes depends on sever factors
- ignition
- Moisture
- Density
- Preheating- the more it preheats the faster it ignites
- Size and form- surface area logs and sticks
Plastics
synthetic materials usually petroleum based
Thermoplastic materials
melt and drip when exposed to high temps, even those as low as 500 degrees. rapidly spreads fires
Thermoset materials
are fused by heat and will not melt as the plastic burns although their strength will decrease dramatically
Standard on Types of Building Construction
NFPA 220
Type I Construction
(Fire Resistive) concrete and steel beams, load bearing walls 3-4 hours some floors 2 hours resistance, large occupancy buildings schools, hospitals, and high rise buildings, parking structures
Type II Construction
(Non Combustible) must be made of noncombustible materials. 1-2 hours
Single story warehouse or factory buildings, concrete floors, concrete block walls steel frame and metal roofing (sprinklers)
Type III Construction
(Ordinary) Look out for hot spots and fire spread 1-2 hour fire resistance, 4-6 story buildings ex. strip malls and apartments. Made of masonry exterior walls made of wood and plaster/gypsum. Materials used to build and individuals contents fuel fires
Type IV Construction
(Heavy Timber) more difficult to ignite exterior consist of masonry construction and interior columns beams floor assemblies and roof structures that are made of wood. no concealed spaces or voids
Type V Construction
(Wood Frame) most common all major components are constructed of wood or other combustible material.
- Balloon Frame Construction
- Platform Frame Construction
Balloon Frame Construction
popular between the late 1800s to mid 1900’s made of continuos studs from basement to roof creating channels for fire to spread.
Platform Frame Construction
almost all modern wood frame construction exterior wall studs are not continuos, each level the floor platform blocks the path of any fire rising within the void spaces.
Building Components (7)
Foundations- shift can cause collapse
Floors and ceiling- vertical fire spread
Roofs- not designed to be as strong as floors
Trusses
Walls
Doors and windows
Interior finishes and floor covering
Dead load
weight of the building itself
Live load
the weight of the building contents
Pitched Roof
sloping or inclined surfaces, used on many houses and commercial buildings FF always in risk of falling in wet or icy weather
Rafters
solid wood joists mounted in a inclined postion. look for spongy roof for collapse
Curved Roofs
often used for supermarkets, warehouses industrial buildings, arenas auditoriums, bowling alleys (bowstring)
Flat roofs
houses, apartment buildings, warehouses, factories etc. slight slope needed to drain water. Flat roofs may have a second roof (rain roof) making ventilation difficult.
Truss
triangular geometry creates strong rigid structure that can support a load much greater than its own mass. large voids allow fire to seep in, one component is compromised the whole structure fails
Parallel chord truss
support flat roofs two parallel horizontal members connected diagonally
Pitched chord truss
typically used to support a sloping roof. triangle
Bowstring truss
the same shape as an archery bow warehouses, supermarkets
Load bearing walls
support portions of building weight (dead load) and its content (live load) compensation of these walls may cause collapse
Nonbearing walls types
- Party walls (fire wall)
- Fire partitions
- Fire enclosures
- Curtain walls
Party walls
constructed on the line between two properties and are shared by a building on each side sometimes a fire wall
Fire Partitions
interior wall that extend from a floor to the underside of the floor above.
Fire enclosures
Fire rated assemblies that enclose interior vertical openings, suc as stairwells elevator shafts and chases for building utilities.
Curtain walls
non bearing exterior walls attached to the outside of the building.
Window regulations
NFPA 80
Doors (3)
- Hollow doors provide little resistance
- solid core provide some resistance
- Metal doors durable and fire resistant
Fire fighters use windows as
- light, vent, exit, entry
Parapet
18-36 inches roof extension to hide appliances on roof may require FF to get additional ladder to mount roof
90 degree fall
length of wall=collapse zone
Collapse Zone
Y=1/2X, X= height
Mobile/modular Homes
light weight building components. Death rate in mobile homes fires is three times that of other types of homes.
Class A
openings in fire walls and in walls that divide a single building into fire areas
Class B
Openings in enclosures of vertical communications through buildings and in 2 hour rated partitions providing horizontal fire separations.
Class C
Openings in walls of partitions between rooms and corridors having a fire resistance rating of 1 hour or less
Class D
Openings in exterior walls subject to moderate or light fire exposure from outside the building.
Class E
Openings in exterior walls subject to moderate or light fire exposure from outside the building
Floor Collapse Pattern (5)
- lean to
- v-type
- pancake
- Canti lever
- Tent collapse
Masonry wall collapse
90 degree inward/outward
Wood collapse
90 degree inward outward lean to
Flat roof
mx layers make venting difficult
fire retardant treated wood
fire retardant chemicals react with gases and tars covert h20 to “carbon char” char acts as a insulator
