Understanding components allows for better understanding of risk involved. Components are:
foundations, roof, floors and ceilings, trusses, walls, doors and windows, finishes and floor coverings
Dead load vs Live load
Dead: weight of the building itself
Live: buildings contents
How are fire resistive floor ceiling systems rated?
terms of hours
What type of floors are common in fire resistive construction?
concrete
What type of floors are common in non fire resistive construction?
wood
What size beams will you find in heavy timber construction? Floor thickness?
8-14" in depth
floors: 2-3" base + 1" finished covering
will often contain a fire for an hour
conventional wood flooring thickness and fire rating?
much lighter than heavy timber, 20 min
lightweight construction?
very thin layers and lightweight engineered joists: failed in 6 min
What is a ceilings primary function?
to hold light fixtures and diffuse light
mainly included in buildings for appearance reasons
Are roof designs as strong as floors?
not necessarily, especially in warmer climate areas
What are 3 primary roof designs?
pitched, flat, curved
What are some variations of pitched roofs?
gable, hip, mansard, gambrel, lean to
Rafters
solid wood joists mounted in an inclined position
Modern lightweight construction trusses
-manufactured using gusset plates (3/8" depth)
-structural component composed of smaller pieces joined together to form a triangular configuration or system triangles
-often fail with no prior warning
which shingles were used in ancient times and are either flat or rounded?
clay tiles (mission tiles)
Where do you normally see curved roofs?
supermarkets, warehouses, industrial buildings, arenas, bowling alleys, churches, etc
Flat roofs
-found on apartment buildings, shopping centers, schools, etc
-slight slope for water drain off
-support systems usually wood or steel
What happens to steel when it is heated?
elongates - can crack the outside walls
flat roof coverings consist of:
vapor barrier
thermal insulation
water proof membrane
drainage layer
wear course
parallel chord truss
two parallel horizontal members connected by a system of diagonal and sometimes vertical members.
top and bottom piece = chord
connecting pieces = web members
bowstring truss
like an archery bow
-top chord is curved
Does checking the roof or floor for a spongy feeling in modern lightweight construction ensure safety?
no
Do trusses have a high surface to mass ratio?
yes
-burns quickly and will fail quickly, failure in one sot results in total failure, gusset plates especially prone to failure
How long will a 100' steel beam or truss elongate when heated 1000F?
9 inches
Should FF go on truss loft roofs?
no
load bearing wall
-provides structural support to building
-interior or exterior
nonbearing walls
support their own weight
party walls
on the line between two properties, almost always load bearing, can be a fire wall too but not always
fire wall
designed to limit fire spread from one side of the wall to the other, constructed of fire resistive materials
-extend from foundation to roof
fire partition
extend from floor to underside of floor above
-often divide floors into separate fire compartments
fire enclosures
fire rated assemblies that enclose interior vertical openings, such as stairwells, elevator shafts, chases..prevents fire from spreading floor to floor via the opening
curtain wall
non load bearing exterior walls
-often serve as a skin on high rise steel frame buildings
Solid load bearing masonry walls 6-8" thick can be how high?
6 stories
solid masonry wall
will have a kings row pattern every 7th course
-otherwise it is probably a veneer
solid core door provides what fire resistance?
20 min or more
How fast will fore destroy a manufactured home?
a few minutes
Fire doors and windows are tested per what NFPA?
80
Where are fire windows located?
in fire walls, often made with wired glass to withstand high temps
death rate in mobile homes vs standard homes?
3 times as high
Buildings under construction
high risk for fire due to:
wood framework is exposed, lots of vent openings, sprinklers inop, additional fire loads with lumber piles, flammable gases and liquids for construction, unoccupied for periods of time
majority of FF death in residential structures due to:
structure collapse, usually floors then ceilings
pre incident planning
identify type of building construction and hazards prior to any incidents