Learn key firefighting procedures for gas leaks and fires, including LP gas and city gas safety measures, evacuation protocols, and explosion risk prevention

LP Gas (Liquefied Petroleum Gas)

• LP Gas, composed of carbon and hydrogen compounds, primarily consists of propane and butane. In household usage, it is commonly referred to as propane gas.
• Propane has a specific gravity of 1.55, making it heavier than air, causing it to accumulate at lower levels.

Firefighting Activities

• Upon arrival at the gas leak site, check wind direction and speed. Use a gas detector to estimate the leak location.
• Position fire trucks upwind and prepare hoses to prevent secondary disasters.
• Ensure firefighters wear protective clothing, wetting it if possible to prevent static electricity. Only use explosion-proof lights.
• Notify the relevant LP gas company, typically found on the gas cylinder or meter.

Setting Up Safety Zones

• Establish fire and emergency safety zones up to where the gas is detected.
• Public announcements should include the safety zone boundaries, prohibition of open flames, and evacuation instructions.
• Lead urgent evacuations and request police assistance for others.

Gas Shutoff

• Generally, the gas supplier handles shutoff, but if urgent, firefighters may shut off the gas.
• Close the gas cylinder valve by turning it clockwise.
• If pipes are damaged, use gas leak tape.
• Avoid shutting off gas if there is visible accumulation or a large leak.

Gas Diffusion

• For indoor leaks, open windows and doors, and use water mist to disperse the gas.
• For outdoor leaks, remove manhole covers and other barriers to allow gas to disperse, particularly if it has accumulated in low areas.

Ignition

• If leaking gas ignites, position firefighters at a safe distance behind concrete barriers. Avoid areas where gas may accumulate.
• Approach the leak using water mist to protect firefighters.
• Do not extinguish burning gas directly as it can lead to secondary explosions. Focus on preventing fire spread and let the gas burn out naturally if possible.

Cylinder Safety Valves

• When overheated, gas cylinders release their contents through safety valves, which can cause a sudden flame burst.

Explosion Risks

• Gas cylinders can explode upon ignition, causing rapid and loud explosions, spreading fire and debris.

City Gas

• City gas is primarily methane, supplied through underground pipes. It is lighter than air and tends to accumulate at higher levels.
• Similar procedures apply for city gas leaks, with the key difference being the supply method: city gas is through pipes, whereas LP gas is supplied in cylinders.

Gas Concentration Measurement Units

• ppm (parts per million): Used for low concentration measurements.
• vol% (volume percent): Used for higher concentration measurements.
• %LEL (Lower Explosive Limit): Indicates the concentration at which gas can explode.
• %UEL (Upper Explosive Limit): Indicates the maximum concentration at which gas can burn.

Common Combustible Gases and Their Lower Explosive Limits:

• Hydrogen (H2): 4.0 vol%
• Methane (CH4): 5.0 vol%
• Propane (C3H8): 2.1 vol%
• Ethylene (C2H4): 2.7 vol%
• Acetylene (C2H2): 2.5 vol%
• Toluene (C6H5CH3): 1.2 vol%
• Methanol (CH3OH): 6.0 vol%
• Ethanol (C2H5OH): 3.3 vol%
• Gasoline: 1.0 vol%
• Carbon monoxide (CO): 12.5 vol%
• Ammonia (NH3): 15.0 vol%
• Hydrogen sulfide (H2S): 4.0 vol%

Gas Cylinder Colors

• Gas cylinders are color-coded based on their contents, as regulated by the High Pressure Gas Safety Institute of Japan. For example, firefighter air tanks are gray.

By understanding these procedures and safety measures, firefighters can effectively manage gas leaks and fires, ensuring the safety of the public and minimizing damage.

Reference page: Fire Fighting skills are crucial, and everyone must improve them.

Reference page: This training focuses on teaching firefighters to safely navigate wire entanglements and remove SCBA in emergency situations, ensuring effective response during critical scenarios.

References　National Fire Protection Association (NFPA)

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