• Assessing Risks
• Avoiding Hazards
• Emergency Planning

Detecting Flammable Gas Leaks

Leakage of flammable gases may result in a fire. In the event of a gas leak, first identify the gas and take appropriate action.

The tabled data below provides you with procedures for dealing with leaks for the following gases: dissolved acetylene, LPG and hydrogen.

Dissolved acetylene (DA)

Identifying features:

• hissing sound and often a garlic-like smell will reveal leakage from a dissolved acetylene cylinder
• specific gravity of gas: 0.9
• dissolved acetylene is lighter than air and therefore will dissipate into roof spaces

Problem - suspected leak

Action - suspected leak

• Check to see if valve is properly closed using moderate force (hand tight)
  Perform a leak test

Problem - persistent leak

Action - persistent leak

• Extinguish all ignition sources
• Evacuate personnel from the area
• Move the cylinder to a safe position - outside and away from drains.  Keep the leak uppermost and take care to ensure further risks are not encountered along the way
• Cordon off the area
• Warn everyone in the area of the gas leak and give priority to those downwind or downhill
• Inform BOC and call the Customer Service Centre on 0800 111 333
• Ensure the work area is thoroughly ventilated before returning

Problem -ignited leak

Action - ignited leak

• Extinguish all ignition sources
• Wear leather gauntlet
• Extinguish the flame with a dry powder extinguisher or a wet rag - but only if it is safe to do so
• Close the cylinder valve
• If the flame from the cylinder has started a secondary fire, or is heating the cylinder, evacuate personnel to a safe location
• Call the fire service
• Inform BOC and call the Customer Service Centre on 0800 111 333

Hydrogen

Identifying features:

• hydrogen is colourless and odourless
• hissing will reveal leakage from a cylinder valve
• specific gravity of gas: 0.7
• hydrogen is lighter than air and will therefore gather in roof spaces

Problem - suspected leak

Action - suspected leak

• Hydrogen burns with an invisible flame
• Ensure the suspected leaking gas is not ignited before approaching the cylinder
• Look for evidence of heat haze
• If a leak has ignited, follow the 'ignited leak procedure' below
• Check to see if the valve is properly closed using moderate force (hand tight
• Perform a leak test

Problem - persistent leak

Action - Persistent leak

• Hydrogen burns with an invisible flame
• Ensure the leaking gas is not ignited before approaching the cylinder
• Look for evidence of heat haze
• If a leak has ignited, follow the 'ignited leak procedure' below
• Extinguish all ignition sources
• Evacuate personnel from the area
• Move the cylinder to a safe position outside
• Keep the leak uppermost
• Take care to ensure further risks are not encountered along the way
• Cordon off the area
• Warn everyone in the area of the gas leak and give priority to those downwind or downhill
• Inform BOC and call the Customer Service Centre on 0800 111 333
• Ensure the work area is thoroughly ventilated before returning

Problem - ignited leak

Action -  ignited leak

• Extinguish all ignition sources
• Wearing leather gauntlets
• Extinguish the flame with a dry powder extinguisher or a wet rag - but only if it is safe to do so
• Close the cylinder valve
• If the flame from the cylinder has started a secondary fire, or is heating the cylinder, evacuate personnel to a safe location
• Call the fire service
• Inform BOC and call the Customer Service Centre on 0800 111 333