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:
Gas leaks are ________ and ________.
Among the most common
POTENTIALLY the most deadly
Components of an oil burner are divided into the following ______ systems:
Oil handling and controls
Most common oil burner is:
High-pressure gun type
Pressures from oil pump in the gun
-100 psi - homes
-300 psi - large installations
Oil burner: 2 sources of ignition
Gas pilot light OR
2 high voltage electrodes (5,000 or more volts)
In control system, limit control and limit switches are?
Limit control - thermostat (most common)
Limit switches - pressuretrol (steam)(min and max setting) and aquastat (steam and hot water)
______ (extremely important to the fire dept) is the preferred means of interrupting the operation of the burner.
Remote control OR emergency switch
Stack switch is a _______ switch designed to sense heat in smoke pipe.
It's main purpose is to ____
On newer burners, stack switch may be ______
Act as safeguard, keeping oil/air from building up w/no fire present.
Infrared sensor at burner head
2 possible oil burner problems
-turn off emergency switch
-turn off oil tank valve
-Inform owner/written notice
Delayed ignition OR kickback
-ignition doesn't occur, oil vapor cloud ignites at once
-loud thud, similar to explosion
-knock smoke pipe loose OR blow open burner
For kickbacks or "explosion in the cellar", and oil burning OUTSIDE the burner:
Oil burning INSIDE the firebox after kickback (normal):
Let it burn itself out
White Ghost is:
LEAST common problem but MOST dangerous
Cloud of vaporized oil and air heated above flash point AND out of its container
Common during severe cold spells
The culprit in roach bombs causing explosions:
Pilot light on stove
Roach bombs and ______ are "real recipe for disaster"
Heavy rolling clouds violently twisting skyward indicate:
Extremely hot smoke
Compactors resemble incinerators, with hopper doors on each floor. Compactors differ from incinerators because:
They aren't designed to hold fire at any time.
Smoke coming from a compactor indicates:
Immediate action is needed.
-stretch hose to first floor ABOVE the fire
Compactors rooms pose the following hazards (5)
High-pressure hydraulic hoses
Moving rams that can shear off AN ARM if caught in compactor
Exploding bottle and cans
The _____ of a compactor fire can be the difference between a routine fire and a rapidly spreading multiple alarm.
Battery powered CO detectors
Won't reset quickly
Like human body, absorbs and holds on to CO for a long time
Gel sensor, 24-48 hrs to reset
Sometimes high-dose accumulation won't reset and must be replaced
Life span 5-7
*120v reset quickly*
CO alarm levels
Low - 15 ppm over 8 hr day or 30 day time frame
(8 or 30 Depending on when detectors are made)
High - 100 ppm in 90 min or 400 ppm in 15 min
Compressed propane shrinks to ________ of its original volume as a gas
Emergency responses-Working knowledge of how to handle these emergencies is _________.
Vital to efficient performance of duty
Natural gas emergencies divided into three basic categories:
Inside leaks (greatest danger).
Outside leaks (next most dangerous).
Leaks resulting from fires
City gate stations pressure
Potential for mass disaster (failure of )
Pressure reduced further
District regulator stations
(FD can't do anything DIRECTLY to solve problem, only notify utility)
Low pressure systems
Operating at 1/4 psi
Gas mains are all at 1/4 lb of pressure
Street main at 2.5-60 psi
Gas line going into premises from street has own regulator
Reduces to 1/4 psi
First priority of report of gas leak should be to:
Notify the utility
How strong is the smell?
Strong-potentially serious, leave premises (expect the worse)
Not so obvious-intensity and evac decided by officer in command
Combustible gas detector
Indicates concentration of gas, expressed as percentage of LOWER explosive limit (LEL)
For faint odors, always check __________. Try to isolate as close to source with __________ and if that isn't possible, next point of control is _________.
Quarter-turn appliance valve
Meyer wing cock
At multiple tenant occupancies, master valve called a _________ stops the flow to ALL the tenants.
Service entrance cock
Natural gas-Where to vent?
Simple-vent upper areas.
Opening windows-generally sufficient.
PPV-more effective means
*NO smoke ejectors*
Search and vent = 👍🏻
Some utilities mix in _____________ to make up difference between supply and demand, called __________.
Liquified petroleum gas
______ is a mixture of several of the hydrocarbon gases, mostly propane, but with quantities of butane and possibly ethane.
A ________ is a particular threat to firefighters, since it often occurs after the arrival of the fire department, unlike most fuel-air explosions.
Pressure relief valve on a LPG cylinder keeps pressure inside at around _________.
LPG cylinder evacuation distance for BLEVE:
150 ft in all directions
Lowest floor with smoke will usually have fire on it. FF should make a point of checking ____________.
At least one floor below this level
Heavy smoke throughout building with no visible fire indicates ________. Even more apparent if smoke is issuing from ________.
Fire in an early state. _____ is the only clue there is a problem.
Smoke/odor of fire
This minimizes damage and generally doesn't affect the security of the apartment. If forcible entry is required, arrange with ____, ____, or _______ for security of apartment.
Fire escape as another view of the structure and it permits forcible entry.
Police, responsible tenant, or building maintenance
Trash compactor chute and incinerator shafts are __________________. A fire in ________ isn't necessarily an emergency.
Abnormal, life-threatening conditions
If smoke comes out when the door is opened, you are ______ the blockage. (Blockage not on fire, incinerator/compactor is)
There is no alternative to ____________.
Building evacuated until checked.
Testing with meters.
CO Alarm values (battery):
CO acceptable levels:
Low-15 ppm, over 8 HR day or 30 day time frame
High-100 ppm for 90 min, 400 ppm for 15 min
9 ppm for residences, 35 ppm for commercial where no one sleeps
CO-If you find defective or leaking appliance, __________________.
Shut it down and continue to monitor
After reading complete, you should begin to vent