Incidents - Common Flammable Gases

Scope

This Operational Guideline is to be considered for incidents involving common flammable gases. It specifically addresses, but is not limited to, the commonly encountered colourless, flammable gases including:

• Liquefied Natural Gas (LNG);
• Liquefied Petroleum Gas (LPG);
• Acetylene;
• Hydrogen;
• Propane; and
• Methane.

Fundamental Protocols underpin the actions of all NSW Rural Fire Service (RFS) members and must be adhered to at all times. They outline the Principles of being an RFS member and provide guidance on conduct to support the safety and wellbeing of members.

Guiding Principles

When responding to an incident known to involve flammable gases, consider:

Approach

• For large volumes, read in conjunction with RFS OPG - Hazmat Incidents.
• Approach the incident upwind and uphill; and not in line with the ends of cylinders. Stay clear of spills, vapours, fumes, smoke, and potential hazards.
• Flammable gases are easily ignited by heat, sparks, or flames and will form explosive mixtures with air and may lead to a Percussive Unconfined Vapour Cloud Explosion (PUVCE).
• Fires involving LPG and Propane require additional Boiling Liquid Expanding Vapour Explosion (BLEVE) safety precautions.

Rescue/Suppression

• As an immediate precautionary measure, isolate spill, or leak area for at least 100 metres.
• Do not extinguish burning gas without first cutting off the leaking gas supply.
• Small fires may be extinguished with Dry Chemical or CO² extinguishers; for larger fires use water spray or fog.
• Where possible, turn leaking containers upright so that gas escapes rather than liquid. Stop the leak if you can do so.

Overhaul

• Cool alight containers with flooding quantities of water until well after the fire is out.

Special Considerations

• Gases may be heavier or lighter than air and this impacts whether they rise and disperse, settle in low places, or collect near the ground.
• While this Operational Guideline addresses gases that are colourless, hydrogen is the only gas which produces fire that is difficult to detect as it burns with an invisible flame. Consider using a thermal imaging camera (TIC) or a long wooden object (such as rake hoe handle, which will become alight) to assess whether the gas is on fire.
• Cylinders containing Acetylene that have been exposed to flame impingement may undergo chemical changes. This may lead to internal heating and the failure of a cylinder well after the fire is out. As a precaution immerse in water and monitor with a TIC.
• Wear structural personal protective clothing and equipment (PPC/PPE), including Self-Contained Breathing Apparatus (SCBA), where possible.

Related Information

• RFS OPG - Hazmat Incidents

Common Flammable Gas Properties

The Australian and New Zealand Emergency Response Guide Book provides further detailed information on flammable gases and other hazards.