Brannigans Building Construction CH.6 Features of Fire Protection (PT.3) Flashcards
preplanning considerations for standpipes
-sketch fire pump, risers and hose valves locations
-water supply & pressure
-hose valves, (PRVs)
-FDC and zones
-fire alarm connection
basic FF considerations for operating standpipe systems:
-supply FDC
-MAIN CONTROL & RISER ISOLATION VALVES OPEN
-note pressures
-fire pump working
-dry standpipe take longer to fill
if trying to supply FDC on first floor and it is blocked or clogged you may pump through
second floor hose valve in stairwell if hose valve is not a PRV
NFPA 72
National fire alarm and signaling code
transmits change of condition signal (smoke detectors, pull stations, water flow switches, etc)
initiating device
all of the following are example of what? :
-manual fire alarm boxes (pull stations)
-spot/line type smoke detectors
-duct smoke detectors
-spot type/ line type heat detectors
-gas/ flame detectors
-water flow/ pressure switches
-supervisory switches (os&y)
initiating devices
include photoelectric & ionization smoke detectors
spot type smoke detectros
cover an area such as projected beam detectors found in atria
line type smoke detectors
nonrestorable fusible element, fixed temp, restorable bimetallic strip and disc, combination rate of rise/ fixed temp, rate compensation are examples of what detectors
spot type heat detectors
heat sensitive wires for industrial applications such as cable trays are what type fo detectors
line type heat detectors
flame detectors can be
ultraviolet or infrared
indicating devices that signal change of conditions to occupants:
-strobes
-horns
-chimes, buzzers, sirens
-speakers
-lamps
although a standard exist for fire alarm system, no single standard has been established for design of what ?
panels (FD can request w/in jurisdiction according to NFPA 72)
often, initiating device zones are either by
areas of building or type of device; especially in small buildings (smoke detector zone)
some fire alarm systems are co-located with other fire protection and life safety system controls in what of high rise building
fire command center in high rise
aspects of alarm and detection sytstems taken into consideration during preplanning:
-protected areas
-detection/ initiating devices
-alarm panel & remote annunciator location
-type of panel and zoning
small panels indicate the fire detector activation but do not provide all of the main alarm panel features; often found at entry points to building
remote annunciator
if you are doing preplan and find older alarm panel system with red, yellow, green lamps it is critical that you have what?
diagram or info sheet indicating which zone corresponds to which area
are more reliable indicators of actual location of fire than smoke detectors, which can be fooled by migrating smoke
water flow switches
in large or tall buildings with multiple detector activations, usually best to use what to determine fire floor/ area
flow switches
you should not reset alarm system until what has been established
device of origin
modern smoke detectors typically use solid red light on individual detection device to indicate what?
activation
in a high rise building, realistic estimate time between alarm and start of extinguishment is at least how many mins?
20 mins
defined by NFPA 72, any alarm that occurs that is not result of potentially hazardous conditions; sometimes results in penalties for repeated occurrences
unwanted alarm
smoke management systems can take different forms depending upon
building code and design intent of system
smoke management systems can be categorized as:
-smoke control
-purge
-zoned smoke control
-airflow
usually in the form of pressurization to prevent movement into protected areas such as stairwell pressurization system
smoke control
venting of smoke (smoke management)
purge
combination of pressurization and venting; typical in high rises where fire floor is vented and surrounding floors, above, below are pressurized to prevent migration
zoned smoke control
use of high air velocity to stop smoke movement
air flow
key to understanding operation of smoke management system is to look at what?
original design and testing criteria (including type and size of fire it protects against)
IBC & NFPA 92 include design criteria for
smoke control systems
T or F: requirement of general smoke control in high rise was removed from model building codes years ago; only stairwell pressurization system requirements remain
true
most smoke control systems have some type of what that may include diagrams of area protected; toggle switches ti turn on & off fans and dampers
smoke control control panel
smoke management systems can be activated
automatic, manual, or both
poor initiating devices for smoke management system activation b/c they can be remote from location of fire
spot type smoke detectors
most smoke management systems use water flow switches and in the case of atria
projected beam detectors
preplanning smoke management system should include:
-type of system
-location
-design criteria
-auto, manual, both?
-initiating devices
-step sequences
-location of control panel
FF consideration for smoke management systems:
-assess operation
-manual activation= communicate to others
-leave FF at controls
protection systems designed to protect specific type of hazards; use series of piping & nozzles, pressurized extinguishing agent storage containers, fusible links that allow cable to release extingiushing agent
dry chem and wet chem systems
device incorporating an alloy of metals that melts at specific temp
fusible link
protect hazards such as paint spray booths and gasoline station pump islands
dry chem systems
primary protection system used in cooking hoods in restaurants
wet chem systems
similar to deluge water sprinkler system; instead of open sprinkler heads system uses special nozzles to sprain specific pattern and direction
water spray system
system of piping around object being protected, with either automatic water supply connected to detection system or manually operated water supply
water spray systems
these systems typically protect exposed LPG tanks and electrical transformers
water spray systems
used to protect flammable and combustible liquid facilities
foam system
warehouses and aircraft hangers use low or medium expansion foam concentrate injected in water through use of
bladder tank foam concentrate storage container and proportioner
high expansion foam systems using overhead generators are installed in some
warehouses
bulk terminals (tank farms) storing flammable/combustible liquids utilize water supply, network of piping, storage tanks of low expansion foam, proportioners and pumps to apply foam solution to surface of burning liquid through use of foam applicators called
foam chambers
some tank farms apply foam using what; where foam solution is pumped into tank at bottom where it then rises to surface of burning liquid
subsurface injection
uses gaseous carbon dioxide to remove oxygen from fire to extinguish it
carbon dioxide system
can be deadly asphyxiant
carbon dioxide (co2)
used to protect materials that can be damaged by water, such as record storage vaults and printing presses; use SCBA around it
CO2 system
uses piping and nozzle network and supplied by cylinders of CO2 under high pressure
CO2 system
storage refrigerated system used when large quantities of CO2 are needed
low pressure storage
uses halogenated agents such as bromotrifluoromethane (halon 1301) or bromochlorodifluoromethane (halon 1211)
HALON SYSTEM
legacy systems; no new systems installed due to destructive ozone depleting characteristics of agent
halon systems
halons react with fire to inhibit
chemical chain reaction
some halon systems can be found in
record storage facilities and museums (leave no residue)
if halon system is encountered. fire will break down halons into dangerous compounds so what must be used ?
SCBA
new group of gaseous chemical compounds (broadly categorized as either “inert gas” or halocarbon”) that were created to replace halogenated agents; used to protect sensitive equipment; SCBA required
clean agent systems
supplies a fine atomized spray of water mist on the order of 1000 microns or less; use water as extinguishing agent but much less water overall (roughly as little as 100 gallons over half hour
water mist system
used in locations where water supply is scarce; used to protect sensitive equipment by avoiding large amounts of water; mist absorbs large quantities of heat
water mist system
agent applied throughout entire compartment/ area
total flooding
agent is applied to just piece of equipment/ hazard
local
any location where nitrocellulose or any other especially toxic material is stored demands intensive what ?
intensive preplanning with emphasis on defensive operations
blown insulation (w/ large flex hose) represents one giant
blanket of insulation
wrapped and unrolled b/w ceiling joists in long single strips and easy to pull out in sections to check for hidden fires
batt insulation
during overhaul in attic, was is recommended for final extinguishment?
class A foam
when it is impractical to remove all insulation from attic space, it is best to post what?
fire watch and rotate crews for next 24 hours to prevent rekindle
a carpeting should be fought with what type of hose stream ?
solid stream, directed through fire to wet carpet beyond fire, stopping extension (fog stream may push fire)
traditional below-grade, interior attack may often result in smoke damage, which can be reduced by changing what?
access point where attack is initiated
how can smoke damage be reduced in a basement fire?
indirect attack through basement window or selecting alternative entry point like rear basement door
in a basement fire, exposure line should be laid to protect what?
door at top of stairways
firefighters should never advance through a doorway protected by fusible link tripped fire door without
blocking it to prevent it closing or dropping behind them
fire doors in fire walls and both horizontal and overhead roll up doors are triggered by what, sometimes located high up in overhead
fusible links
many fully enclosed air conditioned buildings are under positive pressure; opening a single window on leeward side of building in fire area will
permit excess pressure to vent, taking much of smoke with it
older libraries often used marble flooring, which could can look good after heat exposure but can fail under
FF weight
T or F: some FDCs for sprinkler systems cover only certain portions (floors) of a building
true
standard hydraulic formula add what for standpipe and per floor on top of friction loss calculation
adds 25 psi for standpipe
add 5 psi per floor
weaving a hose vertically through windows of stairway landings can help support
weight of charged vertical 2-1/2 in. supply line
when establishing a water supply in stairway with 2-1/2 in hose, what size gated wye should you use
2-1/2 in
at minimum, when establishing water supply in stairway with hose, it must reach
landing of floor below fire floor
class 1 standpipes are vertical
hollow tubes
if for some reason standpipe cannot be charged at FDC on exterior, what can be done
-2-1/2 in hose lines laid to first floor (or lowest level) discharge valve of standpipe
-couplings and siamese, 2-1/2 in lines can be attached to discharge valve for supplying standpipe
an apparatus driver who encounters a siamese FDC (standpipe or sprinkler connection) w/ frozen or rusted female swivels that cannot be freed can still make the connection by
inserting two 2-1/2 in double make couplings
then attach two 2-1/2 in double female couplings
-created a new FDC siamese
another way to connect to siamese FDC w/ frozen or rusted female swivels is to
twist 2-1/2 in supply hose counterclockwise 4-5 turns
insert male coupling into female swivel
untwist hose clockwise to make connection
attaching what to standpipe, helps make connections made on hose at floor level and keeps all extra weight from hose lines and appliances off standpipe valves
pony section (short 10 ft of 2-1/2 in hose)
quality ascribed to wall, floor, or column assembly that has been tested in standard manner to determine length of time for which it remains structurally stable (or resist passage of fire) when attacked by standard fire
rated fire resistance
