Flashcards in Ch. 19 Fire-Related Emergencies: Incinerators, Oil Burners & Gas Leaks Deck (79)
Natural gas is primarily:
Methane (more than 90%)
- Ethane, up to 5%
- CO and Nitrogen
The presence of _____ in natural gas can sometimes be used by FIRE DEPARTMENTS and UTILITY companies to pinpoint the source of persistent "gas odors" that have no apparent source.
Everyone has "smelled gas". Odorant added at a precise rate, so as little as 1% of gas can be detected. The odorant is generally _____, compounded with sulfides.
As little as _______ of odorant can treat up to _________.
1 million cu. ft. of natural gas
Vapor density of natural gas
Large percentage of total number of FD responses involve incidents in which no fire is present OR fire is within its normal container, may be termed:
Pipeline leak: FD operations should be:
-EVACUATING endangered area.
-PROTECTING exposed bldgs and EXAMINING for gas seeping into them.
-NO attempts at closing any valves
2 kinds of regulators (natural gas)
1/4 psi diaphragm.
column of mercury maintain pressure on diaphragm,
being phased out.
Regulator holds pressure between 2 and 4 psi
Regulators inside a building have the vent line piped out through the wall to a:
Peck vent OR fisher vent
Steps for gas regulator failure:
Search for gas, fire and victims
Flammable range of natural gas
4 - 14%
(5-15% in hazmat)
Markings on radio for intrinsically safe:
Class 1, Division 1 or 2 atmospheres
Natural Gas-Curb valves control the gas service into building. As a guide:
Inside services, high pressure-Yes
Outside meters, low pressure-No (O's)
Deciding WHEN to vent:
How large a leak
Source of ignition/can you control them
Status of gas/air mixture
(Natural gas) Of all decisions to be made, _______ has the most variables.
WHERE to stop the leak-inside or outside
Gas emergencies usually involve ______ engine company(s)
At least 1.
enough personnel to stretch hoseline.
long enough to cover ENTIRE building.
Apparatus for most shielding.
Gas leaks usually take _________.
Path of least resistance-underground along gas pipe or other underground lines, gas deodorized as it travels, soil filters out odor.
Nose can detect _____ of gas in air
1%. desensitized after short time. combustible gas meter (explosimeter), 2 meters preferable.
Do's and Don't's of outside leak
-stop leak in low-press. STEEL lines (to save a life!!).
-have dry-chem and water ready if someone enters trench.
-touch valves in street.
-EVER attempt to stop leak in plastic pipe.
Vapor density for propane and butane
Butane - 2.01
Propane - 1.52
Barbecue: Leak of LPG (liquid petroleum gas) near the neck AND accompanying fire
-small fire, if on low-pressure side.
-extinguish by turning off valve OR garden hose.
-isn't done because = lack of knowledge or fear of injury
To avoid casualties involving LPG (BLEVE), FF's need:
-working knowledge of LPG properties
-cylinders in which it was shipped
-tactics for dealing with scenarios
LPG or propane leaking finds source of ignition after having the opportunity to spread out farther and mix with more air
Vapor-air explosion (or fuel-air explosion)
-MORE devastating than leak that ignites immediately or BLEVE
Flammable range = 2.1 - 9.5%
VD = 1.52
Boiling point = -44F
Propane pressure at 70 and 100 degrees
70F = 100 psi
100F = 190 psi
BLEVE isn't caused by _____ but by ______.
Rise in pressure
Loss of strength due to heat
-steel at 1500F loses HALF its strength
How many handlines and stream pattern for LPG cylinder.
Three or four 1 1/2 in. or 1 3/4 in. handlines (within exposed bldg, outside protect structure, cylinder fire)
Initially, straight or narrow fog
-as distance DECREASES, fog gets WIDER so as not to knock over cylinder
*open spaces-extinguish, built-up areas-Isn't recommended*
Heating systems account for _____% of all fires
Modern oil burner consists of: