large commercial fires Flashcards
large commercial occupancies usually range in size from ___ to over 100,000sqft
20,000sqft (282)
large commercial occupancies typically are wide open areas with no __ __
fire breaks
in large commercial occupancy there are typically only __ or possible ___ common entry points
1 or possible 2
many of the tactics and strategies used on large commercial occupancies are similar to those used on __ __ buildings
high rise (284)
large commercial occupancies have _____ located throughout the store
standpipes
the absolute goal of any rescue effort should always be
your own survival
a good rule of thumb for large commercial occupancies is if you cant walk ___ into the building due to smoke, don’t enter
upright (285)
what is the most common type of construction in large commercial buildings
type II unprotected (285)
what is meant by type II unprotected
the major components are noncombustible, but do not possess fire resistant properties
in type II unprotected the exterior wall are constructed with concrete or some other masonry unit and the roof assembly will be supported with ___ steel
unprotected
will a unprotected, noncombustible building provide structural stability under fire conditions
no
what are the factors at which unprotected steel members will fail:
ceiling height of the building
dimensions of the steel
intensity and duration of exposure
apply water to exposed steel will keep it cool and help retain its ___
strength
a __-__ of the roof must be done before any roof operations are conducted
size up (286)
the __-__ must be systematic and thorough but must not delay ventilation
size up
what are the 2 most common roof coverings on commercial buildings
plywood
corrugated steel
__ __ roofs are generally covered with some type of insulation, felt and either asphalt roofing material or synthetic rubber material
corrugated steel
what are the most common walls used in the construction of commercial buildings
tilt up concrete
cement masonry units
steel will elongate approximately __ “ per __ ft under severe fire conditions
1” per 10ft
always establish a collapse zone ___ times the height of the building
1 1/2
the ___ is a partial floor between the 2 main stories of a building. this must be considered in the search and location of the fire
mezzanine (287)
the majority of large commercial fires will be controlled by the ___ system during the early stages of the fire
sprinkler
common roof construction used on large commercial buildings is composed of corrugated steel decking laid over ___ bar joist trusses
steel (288)
many tilt up commercial buildings use ___ wood decking to construct their roof
lightweight
many tilt up commercial buildings use lightweight wood decking to construct their roof. a 3/4 “ plywood or wager board decking is covered with __ and asphalt roofing covering and sealed with mopped on tar
felt
large open flooring should raise a flag of concern because they are indicative of ___ truss construction
lightweight
dropped ceiling should always be checked for __ __ before advancing underneath them
fire extension (289)
if a __ __ is used be aware that the utilities installed in these spaces will prohibit the roofing material from falling through. therefore you have not ventilated
drop cut
____ construction is the least stable of all construction types and Is the most susceptible to collapse because unprotected steel is used to support the roof
noncombustible
steel is a __ performer in a fire
poor
another reason large commercial buildings are susceptible to collapse are the large spans supported by ___ construction which is unstable under fire conditions
truss
the following are characteristics of __ when exposed to fire conditions:
at 400 degrees it begins to lose strength
expect it to fail at approx. 1000 degrees
at 1200 degrees it will have lost 60% of its strength
it expands and pushes out walls causing roofs to drop
steel
what are the characteristics of steel when exposed to fire conditions
at 400 degrees it begins to lose strength
expect it to fail at approx. 1000 degrees
at 1200 degrees it will have lost 60% of its strength
it expands and pushes out walls causing roofs to drop
the failure rate of __ when exposed to fire depends on several variables:
the size
the load it is subject to
the temperature and distance of the fire
steel
the failure rate of steel when exposed to fire depends on several variables what are they
the size
the load it is subject to
the temperature and distance of the fire
roofs constructed of lightweight steel bar trusses can be expected to fail in as little as __ min under moderately heavy fire conditions
5 (290)
larger trusses with column support should hold up better, but can still fail under __ fire conditions
severe
2 1/2” lines can apply over 300 gpm to the fire for ___ feet away
100
large open areas allow us to extinguish fire and protect immediate exposures ___ distances
safer
if a ___ tactics are going to be implemented then the goal will be to advance towards the fire as quickly as possible
offensive
standpipes that are strategically placed inside large commercial properties can be a huge advantage to tactics because they enable us to add additional attack lines without long hose lays being stretched from the exterior. what does this do
increases water flow and decreases friction loss
many larger occupancies will have __and ___vents installed
smoke and heat
from the interior smoke and heat vents look like skylights but are actually ___ vents that enable automatic vertical ventilation
fusible
besides __ systems smoke and heat vents contribute to the successful extinguishment of fires more so than any other component in large commercial buildings
sprinkler