Ch. 4 Classifying Buildings—NFPA 220 System Flashcards
3 step process to size up
Pre incident study
Pre fire familiarization
On scene and pre and post incident review
Initially, the author states to use these 4 ways to classify a structure
NFPA 220
Era
Occupancy
Size
Combustible
Will burn
Limited combustible
Have one half the heat potential of wood, no over 3500 but/lb
Douglas fir is 8400 but
Noncombustible
Will not ignite, burn, support combustion, or release flammable vapors when heated
FRR, Fire resistance rating
Length of time to burn through a given material
Flame spread rating
The length of time it takes to burn across the surface of a given material
Protected
Having an FRR of at least one 1 hour
Unprotected
A material that when exposed will cause degradation and effect structural integrity
Which type of buildings are not easily identified from the street?
Type I and Type II
4 ways to enclose steel in Type I
Concrete
Spray on
Gypsum
Special paint
The intumescent coating is
.5 in thick, will expand 15 to 30 times in a fire
Curtain wall construction can be of:
Glass, tile aluminum, slate, concrete,
How big is the gap on a curtain wall construction
3-4”
3 primary floor plans of Type I
Center core
Center Hallway
Combination of
First Interstate Fire
1988, 3 1/2 hours to control
Burned 45 min per floor
Lapping, curtain wall, have, poke throughs, and radiated heat all contributed to the problems
Primary hazard for Type 1
Contents
What’s the main difference between Type I & II
The FRR ratings are much lower due to steel being unprotected
Primary hazard of Type II buildings
Contents and roof material
3 types of walls in Type II bldg
Unreinforced masonry
Reinforced masonry
Tilt up/pre cast
What type of Wall is most susceptible to collapse
URM- not used anymore-can collapse outward, twice it’s height
Hydra matic fire
Metal deck built up roof
Burned entire 1.5 million squ ft area
MGM
Extension of smoke through HVAC
Vacant warehouse in NV
Tilt wall gave out in 15 minutes
How high can a parapet wall extend
1’-8’
Pipe chase
Think stacked kitchens at apartments or kitchens below bathrooms
Scuppers can
Help show the actual roof behind a parapet wall.
Danger of UMC in Type III construction
Lack of Portland cement and rebar make the wall weak and unstable. Capped by capping stones that have lost their adhesion
Cornices on new Type III
In new Type III construction,nothing more then foam. Cannot support weight
Contributed to Monte Carlo hotel fire
Cornices on older Type III
Stronger than newer ones, but age has worn down the wood and metal. Still not safe
Type III facades
Can conceal hidden fire
Cugees fire
Blame it on layers of roofing being supported by wooden beams that were in lets that gave way
Type IV dean
Shall be that ext walls, and interior load bearing are approved non combustible and limited combustible. Other interior features can be of solid or laminated wood without concealed spaces
Book defn of Type IV
Think masonry wall construction around heavy timber lumberyard
Type IV:
Factories, churches,warehouses, lodges
Large wooden members that are no longer cost effective
Requirements for heavy Timber
8" when supporting floors not less than "6 wide and 8" deep for supporting ceiling T & G of 3" thickness, 1" covering Roof- 2" TG Walls will have a FRR of no less than 2
Are Mills and Heavy Timber the same?
No, Mills were built before many of the Requirements were made, but they are similar
Type IV considerations
Renovations creates voids Lack of sprinklers Petroleum products on flooring Fire cut floor beams and roof joists Large fire load Position away for collapse
4 types of Type V construction
Stacked log
Post and beam
Balloon
Western platform
Chinking is
Paste like filler used in log construction. Went away when builders started planing the logs
How can you spot a LW log construction
Look for log rafter tails only at the corners or at the gable ends with the eaves and soffits finished out like a typical wood frame
Main fire concern for log cabin
Interior geometry and contents
NOT the fact that it is wood
Girts and ribbon boards are also known as
Horizontal beams
Post and Beam
Pole barn construction
Uses mortises and tenons
Large open spaces
The mortise is the _______and the tenon is the_________
Cavity, projection
Fire spread concern for Post and Beam/Pole Barn?
Non finished open spaces creates a firestorm
Weak link in Post and Beam construction
Mortise and Tenon
Balloon Frame
No fire blocking
Continuous studs
Ribbon board on the exterior?
Bungalow construction
2 x4 rafters up to 3’ apart
Visual cues of a Balloon frame construction
Old wood frame up to 3 stories
Old wood ship lap or asbestos siding
Visible 2x4 rafter tails
Windows line up
What is almost mandatory at a Balloon frame fire?
Vertical ventilation, when fire is in the voids
Balloon construction will give some warning before collapse with sagging however, watch out for
Roof collapse due to increased rafter spacing
How is Western Platform different from Balloon
Each floor is separate from the rest
Uses 2x4 or 2x 6 studs
Double plate at the ceiling
What are the two fire stopping elements of Western platform?
The double plate at the top
Fire blocking in the wall
What are the 3 types of Platform construction
Conventional 1800’s- 1940
Legacy 1950’s- present
Engineered
Conventional - Rough finish does what
Chars over and slows the burn rate down
Conventional platform features
Through connections Solid wood-no trusses Lathe and plaster T and G flooring Various roof coverings, osb, 1x6 boards, tar, slate
What are the fire concerns and collapse concerns of Conventional Platform?
The roof will char and slow down the burn, the contents are the main concern
Resistive to collapse due to compartmentalization, but attachments like decks are a killer
Legacy platform can have trusses as long as:
Solid wood
Nails all the way through
No EWP
Though Legacy Platform does not use EWP, how does it differ?
No longer using full dimensional lumber Smooth lumber Galvanized hangers Plywood instead of T and G Cross bracing gave way to plywood sheathing
How is fire concern for Legacy different from Conventional platform?
More opens spaces by design, split levels
Soffits on the underside of eaves and staircases
Split levels allow vertical travel of fire
Discuss Collapse concern for a legacy platform compared to a conventional
Higher surface to Mass ratio
Hangers fail sooner
Craftsman style trusses with solid wood
Engineered Wood Platform-lightweight issues
Reduced dimensional lumber
Glue for connection points
Geometry in place of mass
How long will Conventional/Legacy floors last in a fire?
Light weight construction?
15-20 minutes
5-7 minutes
“Truss space is like horizontal Balloon frame” describes
Lightweight engineered wood platform construction
House fire in Warwick, NJ
Lightweight construction and OSB sheathing
What does tan or brown smoke mean at LW construction?
Degradation of mass has already begun
What has had the greatest negative impact on structural integrity?
LW trusses
