A substance that can kill
In NSW, an apprentice gasfitter was left working alone to extend an existing liquid petroleum gas (LPG) installation. After he cut a live gas main, LPG gas entered the trench where the fitter was working, which caused him to fall unconscious and die. Arrhythmia (disruption to the heart rhythm), was identified in the coronial report as the cause leading to the death, which was because of the effects butane, a normal constituent of LPG. Asphyxiating conditions inside the trench would have been a contributing factor.
Working with LPG
You need to be aware that exposure to LPG is dangerous. When working with LPG, it is vital you know:
- LPG concentrations as low as 2 percent will ignite in air
- gas is heavier than air and will travel along floors, downhill into gullies and will settle in low spots, trenches or basements
- at high concentrations, gas displaces air to cause asphyxiation
- the butane component of LPG has the potential to cause toxic effect.
Connecting to LP gas
When connecting an appliance to LP gas, you should make sure:
- the location of the cylinder must comply with AS1596
- the inscription on a compliance plate must be legible and in letters 6mm high
- that the regulator vent is facing down or cannot enable water ingress.
If an LP gas cylinder has not been tested for 10 years or more, it should not be connected to an appliance. The cylinder should be tagged as defective. Under no circumstances should any attempt be made to modify a gas cylinder.
The dangers of small gas cylinders
LP gas is widely used by trades as a fuel for portable heating equipment, as well as by the public for barbecues and for camping. It is heavier than air, so it will accumulate in low areas rather than dissipate. It can generate an explosive mixture with air if the cylinder or attached equipment leaks. Explosions and fires have occurred when cylinders of LP Gas (propane) or acetylene have been carried or left in closed vehicles, such as vans or cars. Spark sources in the vehicle’s electrical components such as remote locking systems, electric motors (starter motor, wipers, aerial), ignition systems, radios and sound systems, cigarette lighters, and possibly light switches can ignite a flammable gas mixture. Lighting a cigarette in the vehicle will also ignite such a mixture.
LPG cylinders must be transported in the upright position and appropriately secured for transport. Refillable LPG cylinders for gas appliances such as bbqs and heaters must only be filled if they have a current, legible test mark of a certified gas cylinder test station. Periodic inspection intervals for retesting of welded cylinders less than 100 kg water capacity filled with LPG (typically connected to barbecues) is 10 years.
Filling LPG cylinders
Gas cylinder filling stations are only allowed to fill cylinders that have a current, legible test mark of a certified gas cylinder test station. They must also make sure that the cylinder complies with AS 2030 requirements. If a gas filling station, as part of a cylinder exchange, accepts any cylinder that is not appropriately marked, they will have to either:
- make sure the cylinder is inspected and test station-marked in accordance with AS 2030 before filling or refilling, or
- dispose of the cylinder.
Purchasing a new or used refillable cylinder
Ask the retailer to show you the current, legible test mark and confirm that the cylinder they are selling can be legally filled in NSW. If there is no current legible test mark, the cylinder may not be safe to fill. If you decide to purchase a cylinder without a current, legible test mark, the cylinder will need to be inspected by a certified gas cylinder test station and stamped with a test mark prior to filling. The test station might charge a fee for inspection and stamping.
To protect yourself and those working around you from the risk of serious injury resulting from exposure to LPG, do a thorough risk assessment of each and every job:
- Ensure appropriate supervision and inform others on site of potential hazards.
- Isolate the gas supply and drain residual line-gas pressure to where it is safe.
- Provide adequate ventilation, or breathing apparatus.
- Control and exclude all sources of ignition, including power tools and static.
Spill combat recommendations
In the event of a spill from a tank like the one pictured below, follow the Hazchem 2YE spill combat recommendations. Use breathing apparatus and water fogging, contain the spill and consider evacuation. Search UN No.1075 for further information.
The Gas Supply (Consumer Safety) Regulation 2012 sets out the requirements for gasfitting work on gas installations. The procedures required to perform gasfitting work depend on the specifics of the site, which means the licensed installer must assess all aspects of risk for the work to be done safely.