Brannigans Building Construction CH.6 Features of Fire Protection (PT.1) Flashcards
emergence of building codes in the early 1900’s further advanced elimination of
conflagrations
limiting fire spread from building to building is accomplished through
-restrictions on area/height of building
-limits on combustibility of roofs and exterior wall surfaces
-min. separation distances b/w buildings
-limits on openings in exterior walls (doors & windows)
-fire resistive exterior walls
preventing a fire from spreading through a structure is achieved by
-use of fire rated floors
-protection of vertical openings (stairs & elevator shafts)
-compartmentation in form of fire walls & fire partitions
-fire resistive construction (rated columns & beams to prevent collapse and spread of fire)
-use of fire protection systems
primary concern of building occupants in fire protection
life safety
the most important elements of life safety are proper
means of egress (exits) and protection against hazards (based on occupancy and capability of self preservation)
safety of who has become an explicitly stated goal in building and fire odes
firefighter safety
firefighter safety has been regulated by building codes requiring placement of what on exterior of buildings adjacent to elevator and other shafts
shaft way signs
noncombustible buildings can contain significant combustible components including
cornices
wooden interior balconies
sheathing
a quality ascribed to a wall, floor, column assembly that has been tested in a standard manner to determine the length of time for which it remains structurally stable (or resist the passage of fire) when attacked by a standard fire
fire resistance rating
resistance of structural member to collapse by fire b/c of the nature of tis material or assembly
inherent fire resistance
the inherent fire resistance of a structure has never been formally what
rated or required by law
structures that are protected w/ gypsum board and wood assemblies that have passed standard fire resistance test
combustible structures
in 1890, first fire test of fire proof assembly in US was conducted for Denver Equitable Building Company; hollow tile floors were tested and it revealed that porous hollow tiles set in end construction (tile cells at right angles to beams) were superior to
dense tiles set in side construction (tiles cells parallel to beams)
the effort to develop standards for fire resistance brought together
-National Bureau of Standards (NBS; today known as National Institute of Standards & Technology [NIST])
-Underwriters Lab. (UL)
-National Fire Protection Association (NFPA)
-both capital stock and mutual insurance
time temp. curve in NFPA 251 still the same today as it was in
1918
despite general consensus that test of 1928 is outdated it continues to be used to assess fire resistance of every
column, beam, floor, roof, and wall in test labs
materials and assemblies may be classified based on their what
fire resistance; or more accurately on fire endurance
3 standards that are from separate organizations but similar in content and structure about materials and assemblies
-NFPA 251: standard methods of test of fire resistance of building construction and materials (2006)
-UL 263: standard for fire test of building construction and materials
-ASTM E-119: standard test of methods of fire test of building construction and materials
fire resistance of columns is concerned with
resisting collapse
fire resistance of floors is concerned with
resistance of passage of fire and collapse
fire resistance of walls is concerned with
passage of fire and collapse
fire resistance of fire doors is concerned with
passage of fire
fire resistance is not specifically directed at ensuring
life safety
fire resistance can be considered a feature to
life safety
fire resistance is not specifically intended to provide
smoke control
fire resistance is not concerned with loss to what
dollar loss due to fire
provision of test standards UL 263, ASTM E-119, & NFPA 251 require what things with its objective of these provisions being uniformity of testing
-reproducible fire test
-consistent method for conducting test and classifying results
-specific instruction on selection & preparation of test specimen
(do not represent actual fires)
the reproducible fire used in fire resistance testing follows a what that has remained essentially unchanged for more than 100 years
standard time temperature curve
min. size test specimens for fire resistance testing of columns, beams, girders, partitions walls, floors and roofs
columns: 9ft
beams & girders: 12 ft
partition walls: 100 ft^2
floors & roofs: 180 ft^2
during a fire resistance test, load bearing structural elements are loaded w/ prescribed wt for the assembly and then unit passes if
successfully resist superimposed load and in case of partitions, walls, floors and roofs resist passage of fire
when columns are fire tested they have what peened into them?
thermocouples peened into them
when columns are fire tested the average temp or any temp of thermocouples that exceed what cause test to terminate and specimen fails
average temp: 1100F
temp of thermocouples: 1300F
when a floor or wall structure is tested for fire resistance it must not develop what or permit an average temp rise of unexposed surface of what
must not develop conditions that would ignite cotton waste on surface
or
permit average temp rise of 250*F on unexposed surface
assemblies that are test for fire resistance, if they pass they are rated in units of what
hours (1,2,3) depending how long test unit survived fire
rated units after passing fire resistance test are listed in references such as
UL Fire Resistance Directory (published annually)
once fire resistance testing is completed and assembly or material is rated and listed (not the same as approved) who can approve use of specific material or assembly
local authorities such as building department may approve use (permit use as being acceptable to local jurisdiction)
a listed assembly meets what for test; therefore all components assembled as specified in the listing are required to meet the specific listing
meet minimum requirements to pass test
after passing a fire resistance test, a listed assembly is what?
minimum quality structure capable of passing test
achieved from the listing of the entire assembly, not the individual components within the assembly
fire rating
a 2 hour fire resistance rating does not mean what
building will be relatively undamaged for 1 hour
what does a fire resistance rating mean in terms of structure survival of fire
if building react to fire in same manner as specimens did for that particular type of construction in test
and if actual fire load (fire impact) does not exceed the fire test load
and if duration of fire does not exceed time specified for component involved
then structure should survive
time ratings given to fie resistive assemblies do not relate to real time in an actual fire rather the ratings provide a relative measure of
comparison, comparing 1 assembly duration of endurance to another assembly duration
(i.e. 2 hour fire rated assembly simply has greater fire endurance than a 1 hour fire rated assembly)
fire resistance rated assemblies does not necessarily men
noncombustibility
many fire rated assemblies that are listed include combustible components typically
wood beams or studs
the fallacy of arguing that fire resistance rated assemblies represents a complete safe working platform lies in the fact that the test standard was originally developed for
noncombustible floors assaulted by fire only from below
a major deficiency in fire testing for resistance is that the standard does not recognize the fact that nearly all such assemblies have what
wirings running within them
(i.e. electrical wiring inside truss of 1 hour fire rated floor/ rating does not exist if fire starts within assembly)
what of a lightweight wood truss is irrelevant when the fire starts inside the truss because of an electrical failure or other cause
fire resistance rating
concerned with length of time a particular building assembly will continue to perform its structural and/or barrier function in the face of an assault by standard fire rest
fire resistance ratings
concerned with rate at which fire spreads over the surface of am material, the smoke it develops and the fuel it contributes to a fire
flame spread ratings
one of the most important factors in fire spread within buildings is what
interior finishes on wall and ceilings
first attempts to deal with flame spread by codes failed due to what
inexact, legally unenforceable language such as “flame spread no greater than wallpaper”
-test are costly, time consuming and must be consistent
the basis for regulation of fire spread is found in what as is commonly referred to as the Steiner tunnel test
NFPA 255; standard method of test of surface burning characteristics of building materials
also known as
ASTM E-84 & UL 723
the 2 comparison points in evaluating test results of flame spread are flame spread over
inorganic reinforced cement board set at 0
red oak set at 100
flame spread test have shown that fire can reach end of red oak test panel in how many minutes
10 minutes
formula by which the flame spread index is calculated can be found in
NFPA 255
flame spread of surface materials is classified as
- class A: 0-25
- class B: 26-75
- class C: 76-200
most building and fire codes have requirements for ceiling and wall surfaces based on
tunnel test standard (flame spread)
a typical requirement might be for what Class rating for exit stairwells in hospitals
class A flame spread rating
sometimes higher flame spreads are permitted for
sprinklered buildings
model building codes allow for reduction in the class level when sprinkler protection is available but in no case can the rating be less than what
Class C (i.e. A -> B, B -> C, C)
when tunnel test is run at UL, was is also measured and indexed ?
smoke developed
calculated by measuring the obstruction as smoke passes a photoelectric cell placed in the stack from the test tunnel
smoke developed
materials with smoke developed ratings of 300 or more can be expected to generate
substantial amount of smoke
only what is measured in this aspect of smoke tunnel test not any other effects of smoke or gases such as toxicity or irritation
only light obstruction
widely accepted as a flame spread testing standard
Steiner tunnel test
ASTM E-108 (UL 790); Standard Test for Fire Test Roof Coverings is a test to assess what things
- resistance of roof to external fire
- fire spread of roofing surface itself
- propensity of roofing to generate more burning brands
Clay tile, copper sheets, and other similar noncombustible materials are not tested for fire test of roof coverings and are considered what class
class A materials
certain materials such as rubber, recycled plastic and aluminum are tested as what for fire tests of roof coverings?
tested as part of an entire assembly, including underlayment
this type of test place roofing sample on inclined platform similar to peaked roof, then assembly is subjected to flying brand test, intermittent flame exposure test, and spread of flame spread; all using a gas burner
fire test for roof coverings (ASTM E-108/ UL 790); roofing material test
fire test for roof coverings provide 3 ratings for the test samples based on
spread of fire on the roofing surface
fire test of roofing materials 3 ratings for test samples
-Class A: severe fire exposure
-Class B: moderate fire exposure
-Class C: light fire exposure
set specific minimum roof covering ratings depending upon the type of building construction (type 1-5)
IBC & NFPA 5000: Building Construction & Safety Code
the NBS developed ASTM E-162 that test what
Radiant Panel Flame Spread Test (ASTM E-162)
samples for these test measure only 6 by 18in
what type of test was developed by FM Approvals to simulate an actual fire in the corner of a room, given the fac that ASTM E84 tunnel test did not accurately assess the flame spread of foamed plastics on walls
corner test
FM Approval Standard 4880 =
Class 1 Fire Rating of Building Panels or Interior Finish Materials
commercial carpeting presently being manufactures is required to meet a test that measures ignitability of carpeting from a small source such as dropped match or cigarette ; it is a screening test called what
the pill test; 7/8 samples must pass
NFPA 253, standard method of test for critical radiant flux of floor coverings systems using a radiant heat energy source (Critical Radiant Flux test also known as ASTM E648) is used to rate
carpeting for its ability to spread flame when attacked with a greater ignition source that a cigarette
test for wall finish
ASTM E84 & NFPA 265
Critical Radiant Flux test (NFPA 253) measures a materials ability to
resist flame spread
the results from the Critical Radiant Flux test =
critical radiant flux (CRF)
amount if external radiant heat energy (measured in watts per square centimeter) below which a flame front will cease to propagate
critical radiant flux (CRF)
the higher a CRF number =
less flammable the carpet is
if carpeting is flammable, flame spread will probably increase, that is CRF will decrease if what is present
underlayment
acts as an insulator, keeping heat from carpeting from being dissipated to floor
underlayment
when regulated, model building and fire codes consider 2 classes of interior floor finish ratings =
-Class 1: CRF min. >= 0.45 watt/cm^2
-Class 2: CRF min. >= 0.22 watt/ cm^2
a reduction in CRF class is permitted in spaces protected by an approved what
automatic sprinkler system
what caused these changes to be made:
-improved sprayed on fireproofing (adhesion & cohesion)
-provide separate high rise FF stairwell & improved FF elevator access
-require in building radio signal amplification in high rises and other structures
changes made to U.S. building and fire codes as a result of World Trade Center Collapse on 9/11/2001
due to 9/11 many building codes were changed and in addition the very first provisions to allow what for civilian egress during an emergency were put into the building code
special hardened elevators (elevator cabs and shafts that have been fortified against extreme events such as explosions)
in 2004 NIST issued a series of reports in Phoenix, Arizona in wood frame buildings showing that thermal imagers did not offer any help in establishing what
roof deck temperatures directly under the roof
prototype vibration analysis tool, has been developed to monitor vibrations in a structure that might be precursor to collapse
HOBS (Health of Burning Structure panel)
In 2008, UL w/ Chicago FD tested “legacy” construction (traditional wood members) versus lightweight structural members (wood I beams and trusses) for collapse comparisons resulting in
lightweight wooden I beams collapse in 6:03 minutes
legacy 2x10 in beam construction outlasted lightweight construction by a 3:1 margin
specify level of fire resistance in hours and # & type of penetrations permitted
building codes
typically 2-4 hour fire resistance rated and are used to create separate buildings
fire walls
defined in IBC as fire resistance rated smoke tight wall having protected openings, which restricts the spread of fire and extends continuously from the foundation to or through the roof, with sufficient structural stability under fire conditions to allow collapse of construction on either side without collapse of wall
fire walls
typically 1 hour fire resistance rated and are used to create fire resistive corridors and to separate tenant spaces in covered mall buildings
fire partitions
defined by IBC as a vertical assembly of materials; designed to restrict spread of fire in which openings are protected
fire partitions
typically 1-2 hours fire resistance rated and used to enclose shafts, exit stairwells, exit passageways, and horizontal exits and to separate spaces from certain hazardous areas
fire barriers
defined in IBC as fire resistance rated vertical or horizontal assembly materials; designed to restrict spread of fire in which openings are protected
fire barriers
openings in fire resistive assemblies are required to be
fire resistance rated as well
heating ventilating air conditioning (HVAC) system passing through fire resistive assemblies must be provided with
fire damper
are mechanically operated using a fusible link that drops a metal “curtain” or blade inside, blocking passage of fire ; some use pneumatic or electrical activation
fire dampers
combined fire and smoke dampers, typically used in what, also require periodic maintenance
used in smoke barrier or smoke partition
can have fire protection ratings ranging from 20 minutes - 3 hours, depending on type of fire resistance rated assembly in which it is located
fire doors
one of the most important aspects of a fire door is its ability to
close and latch closed
shopping malls have minimum what, which can allow smoke to pollute entire mall
minimum horizontal barriers
tested using NFPA 252, UL10B, ASTM E2074; furnace is used to test
fire doors
doors can close by what 3 methods
swinging
sliding
rolling
most common choice; used in corridors and stairwell openings (doors)
swinging doors
typically found across openings in elevator shafts or stairwells in old factories (doors)
sliding
used in large openings found in modern factories and warehouses (doors)
rolling
sometimes used in buildings; typically rolling fire doors used to protect small openings such as ticket booth window in a rated corridor
fire shutters
2 types of fire door closure devices
self closing
automatic
room or stairway door equipped with an automatic door closer that closes the door after it has been opened is an example of what type of door closure device
self closing type
some stairway door closures are equipped with fusible links which are designed to do what
fail at specific temp and close door when heat from fire is encountered
fusible links of doors are not sensitive to what
smoke
fire walls with automatic fire doors intended to close only in case of fire are equipped with
fusible links
when inspecting fire doors and shutters you should look for:
-operating
-raise counterweights of automatic sliding door and counterbalanced doors to be sure they close
-damage
-all hardware (latches, guides, threshold)
-fusible links (free of paint or other foreign matter)
-proper operation of “door coordinators” ensure opened fire doors (leafs) close in proper order, with good seal
FF’s should not pass through a fire door without
blocking it
doors that are held open by electromagnets, have a door latch system that can be triggered automatically by smoke detectors on either side of the door by
fire, smoke alarm, or sprinkler flow alarm (can also be designed to permit manual release)
2 leaf doors should be checked to see that the doors close in the deigned sequences b/c the roller that accomplishes this task is frequently
damaged from constant use
smoke sensitive doors are controlled individually by one or 2 detectors that trip door as smoke is detected; these doors should not have
latches that hold them open
creating fire areas no larger than one floor; all connections b/w floors designed to stop spread of fire
compartmentation
stairways in new buildings enclosed and provided with self closing doors w/ fire protection rating is considered fireproofing and a concept of
compartmentation
open interior access or convenience stairs installed create what
single fire area consisting of 2 or more floors
open stairs allows what to travel easily
smoke and fire to travel easily from one floor to floor above
after several multiple fatality hotel fires in the 1940’s, an effort was made to
enclose open stairways
used to reduce travel distance and to subdivide (compartmentalize) floors
horizontal exits
typically 2 hour rated wall with rated fire doors
horizontal exit
building codes require hose outlets at the openings of a horizontal exit to ensure
sufficient # of hose outlets are available throughout each floor avoiding excessively long hose stretches
used in healthcare facilities b/c they can be used to move non-ambulatory occupants to a smoke free area; also used in certain underground buildings
smoke barriers
typically 1 hour fire rated and with smoke protected openings, including “smoke” dampers and door sweeps at the bottom
smoke barriers
