TAC #21: HANDLING GAS EMERGENCIES (NATURAL AND PROPANE)

Foundational vocabulary and technical specifications from the Baltimore County Fire Department's Standard Operational Procedure for gas leaks.

Ethyl mercaptan

The odorant added to natural and propane gas by the gas company to make them detectable by smell.

Natural gas flammability range

$$4-15\%$$

Propane flammability range

$$2.1-9.5\%$$

Natural gas vapor behavior

Will rise in air, requiring ventilation from the high points of a structure.

Propane vapor behavior

Will sink in air, requiring ventilation from the low points of a structure.

LPG

Liquid petroleum, composed of propane, propylene, butane, and butylenes.

Inside sources of ignition

Examples include turning on a light, a phone or doorbell ringing, pilot lights, and generating static electricity by walking over carpeting.

300

A minimum of ___ feet from the structure or leak for the first arriving engine.

4-Gas Meter

A device used to make evacuation decisions; if it alarms for LEL, personnel should exit the building unless rescue is necessary.

Sniffer

A device used specifically to locate the source of a gas leak when the 4-Gas Meter shows no alarm.

3

Evacuate the involved structure and __ houses in each direction.

Order of gas shutoff priority

1. Appliance quarter-turn, 2. Meter quarter-turn, 3. Curb valve, 4. Street valve.

Natural gas ventilation method

Ventilate from the top down once the gas is turned off.

Propane gas ventilation method

Ventilate from the bottom up once the gas is turned off.

PPV

Positive Pressure Ventilation (push), used if natural ventilation is insufficient.

Plastic gas lines hazard

Gas flowing through these lines creates static electricity; firefighters should not attempt to stop the flow from them.

BGE

The utility company to be notified during natural gas emergencies.

High-pressure leak airspace control

For leaks blowing upward, air traffic control should be notified to control airspace for media helicopters.

Propane tank cooling requirement

Requires a $500\,\text{gpm}$ water spray per direct flame impingement using an unmanned monitor line.

Emergency vent (Propane tank)

Personnel should not extinguish the flame from this part of the tank.

Ignition Hazard

The ignition of either will result in a violent is-lesion is considered an

Est scene control, isolate the area, deny entry, and evacuate the structure.

OIC Responsibilities