Ch. 5 Fire Behavior and Bldg Constr. Flashcards
Fixed or movable walls and partitions, columns, and ceilings. Commonly refers to finish on walls and ceilings, NOT FLOOR COVERINGS.
Interior finish
plaster, gypsum wallboard, wood paneling, ceiling tiles, plastic, fiberboard
Combustibility of interior finish affects fire behavior: (4)
Contributes to fire extension by flame SPREAD over surface of walls and ceilings.
Affects rate of fire GROWTH (flashover).
Adds to INTENSITY (fuel).
Can produce smoke/toxic GASES (life hazard)
Incidental trim considered trim as long as: (2)
- doesn’t exceed 10% of wall AND ceiling.
- doesn’t constitute “a large continuous surface”
Bldg code exclude surface treatments that are no thicker than ______. A thin product, ______, will propagate flame more quickly with studs and air space, than attached directly to more solid material.
NO thicker than 1/28th in.
1/4 OR LESS
Degree to which fire can spread over the surface of a material is technically referred to as the _____ of a material.
Surface burning characteristics
Speed of flame spread over an interior finish influenced by:
- composition of material
- ventilation
- shape of space in which material is installed
- whether finish of material is applied to ceiling or wall
Interior features such as ____, ____, and _____ have a CUMULATIVE effect on the outcome of a fire event.
- wall coverings
- compartmentation
- fire protection systems
Total amount of heat produced or released to the atmosphere from the CONVECTIVE LIFT PHASE of fire per unit mass of fuel consumed per unit time.
Heat release rate (HRR)
_______ is not by itself a measure of the severity or rate of fire development of a fire. The severity of a fire is determined by _________ plus ___________.
Fire load.
Fire load.
The rate at which the fuel burns
Rate at which fuel burns is determined by several factors. The most important is the ___________.
Combination of fuel and available oxygen.
The tunnel test, NFPA 255, produces a _______ rating of the flammability of the interior materials, which is known as the ______.
Numerical.
Flame spread rating
NFPA 255, UL 753, ASTM E84 Tunnel Test (Steiner) dimensions and temperature
25 ft long horizontal furnace.
17 5/8 in. wide.
12 in. high.
4 1/2 ft. flame.
5,000 btu’s
10 minutes
Three classifications of interior finishes
Class A-0-25, VERTICAL exits.
Class B-26-75 CORRIDORS that provide EXIT access.
Class C-76-200 other ROOMS and SPACES depending on occupancy
rooms of healthcare and assembly occupancies
To derive numerical rating for NFPA 255 Steiner Tunnel, flame spread compared to two standard materials:
Asbestos cement board 0.
Red oak flooring 100.
Fire spread along red oak flooring 24 ft in 5 1/2 minutes
The tunnel test provides an additional measure of flammability: ___________.
The smoke developed rating.
(Photoelectric cell and light source at end of tunnel furnace)
Red oak standard-100 smoke developed rating.
Codes limit max smoke developed to 450
Fire retardant coatings (4)
Intumescent paints-expand upon exposure to heat.
Mastics-thick, noncombustible coating.
Gas-forming paints.
Cementitious and mineral fiber coatings
do not increase fire resistance of structural components unless tested
Fire retardant coatings-
Must be applied at a __________________. May not have permanent effect if used in ___________ or ______________. Fire retardant coatings only affect ___________, not the ____________.
Specified rate of square feet per gallon
In exterior applications OR environments with high humidity
Coated surface, untreated back side of a panel
Tunnel test (255/ASTME84/UL753) is useful because:
- it provides REPRODUCIBLE results AND
- is a widely RECOGNIZED standard
Smoke developed rating ______ an indication of toxicity or volatility. Tunnel ________ detect or measure a completely transparent product of combustion.
Is NOT.
DOES NOT
Materials produce fire hazard greater that tunnel test because: (2)
Flame spread different over a vertical surface than horizontal surface.
Walls and ceiling provide for re-radiation of heat between intersecting surfaces
NFPA 265 is _____________
“Evaluating room fire growth contribution of textile coverings on full height panels/walls” originally developed carpet-like textiles began to be used as wall coverings
NFPA 286 is ____________.
“Contribution of wall/ceiling interior finish to room” to handle materials that may not remain in place during tunnel test (plastics that melt and drip)
IBC allows 286 instead of steiner. No flashover, max 800kW.
2 basic fire protection concepts are:
Active - have a power source, source can be manual=fire extinguisher. Ex. sprinkler or alarm
-extinguishes or controls fire.
Passive - relies on bldg constr. and materials. Ex. firewalls, stair enclosure, fire doors.
-limits spread
Partitions separating individual rooms within an apartment are ___________.
NOT fire rated
Assemblies of building components required by code to have a minimum fire-resistance rating from independent testing agency. Also called _______.
Rated assembly
or LABELED ASSEMBLY
_______ can provide areas of refuge for occupants when immediate/rapid evac is not possible. Concept of providing an area of refuge is referred to as ________ or ________.
Fire-rated partitions.
Defending-in-place OR sheltering in place
requires INTERVENING doors be CLOSED