Compressed gases in cylinders are classified as Dangerous Goods (as well as Hazardous Substances) and must be stored legally and safely. This blog looks at the risks and hazards associated with compressed gases, outlines the requirements for storing them safely, and introduces the risk management process.
Hazards of Gas Cylinders
There are two main types of hazards that surround compressed gases stored in cylinders. The health and physiochemical hazards of the gases themselves; and the physical hazards of cylinders that contain gases which are compressed and pressurised. Let’s look at them both.
Health and physiochemical hazards of compressed gases
Workers can be injured or die from exposure to toxic and corrosive gases (chlorine, ammonia). These gases can cause acute reactions (burns, rashes, blindness) or chronic conditions like asthma and cancer.
Inert gases (argon, helium, neon and nitrogen) are sometimes considered relatively harmless but can asphyxiate workers by displacing oxygen from the air. Many of these gases are colourless and odourless so workers can enter oxygen deficient areas without realising there is a hazard present.
Workers can be burned or die when flammable gases (LPG, methane and acetylene) cause fires and explosions. These fires can be exacerbated by oxidisers (pure oxygen) causing the fires burn hotter making them harder to extinguish.
Gas cylinder physical hazards
Gas cylinders are mostly long, slim designs and can easily fall or be knocked over. Knocks and falls can damage the cylinder and valves causing the cylinder to rapidly disperse gas. An uncontrolled release of gas can create fires and explosions, or even launch the cylinder into a deadly torpedo-like projectile.
Gases can also leak from worn thread, damaged valves and loose connections. Workplace operations (like forklift traffic or objects falling from height) can impact cylinders causing them to heat, rupture or explode.
Finally, workers are very susceptible to manual handling injuries like muscular strain and sprains while moving bulky, heavy cylinders. Mechanical lifting devices and trolleys should be used wherever possible.
Storing cylinders legally and safely
Gas cylinders should be stored according to the guidelines in AS4332-2004 - The storage and handling of gases in cylinders. The Standard outlines the following key areas for compliance:
1. Compliant gas cylinder store
Wherever possible, gas cylinder stores should be located outside to take advantage of natural ventilation as well as isolate these Dangerous Goods from work operations and untrained staff. The stores should be:
- On the ground floor with no space between the cylinders and the ground
- Level and possibly sloped to allow for drainage
- Constructed from non-combustible materials
- Sufficiently ventilated (using natural air flow or a mechanical ventilation system) to maintain safe oxygen levels, and safe gas exposure levels within explosive limits.
A secure gas bottle cage made from heavy duty materials is ideal because the Standard requires cylinders stores to be fenced off and secured against unauthorised access. A gas bottle cage also includes a restraint system that ensures cylinders are stored upright and individually restrained by chains and safety straps.
IMPORTANT: Cylinders must be protected from impact or damage by vehicles and falling objects. Again a gas bottle cage with bollards and bump rails is an excellent way to protect the cylinders and achieve compliance.
2. Correct signage
Gas cylinder stores require clear signage and placards that comply with the WHS Regulation current in your state or territory. Placards and signs must be located outside the storage area, and far enough away to warn someone of the dangers before they enter the cylinder store.
The warning signs and placards should alert them to the type of hazards present (Highly Flammable, Toxic Gas) as well as any immediate precautions they need to take (use PPE, breathing apparatus). Signage must be permanently installed in a place that is clearly visible.
IMPORTANT: Cylinder stores must also contain the Safety Data Sheets (SDSs) for each gas and kept in a Manifest of Hazardous Chemicals.
All gas cylinder stores must be isolated from industrial heat, combustibles, vegetation, refuse, ignition sources, building entrances and openings, as well as other Dangerous Goods.
Additionally, incompatible gases must be segregated within the store. The Standard specifically identifies the following gases to be kept at least 3 metres apart:
- Class 2.1 - Flammable gases (acetylene, LPG)
- Class 2.2 (5.1) - Non-flammable, oxidizing gases (oxygen)
- Class 2.3 - Toxic gases (chlorine)
If it is not possible to place a distance of 3 metres between these gases, a segregation wall should be erected instead. The wall must be constructed from non-combustible materials and stand at least 1 metre higher than the tallest cylinder. The wall must also be impervious to any of the gas vapours.
Gas cylinder storage and risk management
Knowing the requirements of AS4332-2004 is the first step in safety compliance. You then need to identify each of the gases used at your own workplace and the risks they present. Each risk is then assessed and prioritised based on the severity of possible dangerous incidents (deaths, property destruction) and how likely they are to occur.
Control measures are then introduced into your workplace to minimise the harm associated with each gas cylinder hazard. Another risk identification and assessment is then conducted to make sure no new risks have been introduced and everything is 100% compliant.
TIP: Use the STOREMASTA risk management methodology; Identify - Assess - Control - Sustain to ensure that every risk is fully controlled and long term safety compliance is sustained.
To learn how to store the gas cylinders at your workplace legally and safely, why not download our FREE eBook Gas cylinder storage: Compliance and storage requirements. We explain the legal requirements in a clear, easy-to-understand style and use real world examples to make the requirements relevant to your own workplace. Download it today by clicking on the image below: