A number of gases are kept under pressure in cylinders for a variety of applications in industry, medicine, catering and leisure. Safe storage of gas cylinders in workplaces cannot be taken lightly.
In every case the gas is compressed to make a larger volume fit in a smaller space than it would take at normal atmospheric pressure. Often this is for convenience, but it can also be because the pressure involved in storage is important, such as using fire extinguishers, inflating life rafts, lifejackets, or emergency chutes on aircraft, and even fizzy drinks makers.
Some cylinders can be large and heavy, adding to the need for care in storage and transporting them. The main hazards are, in no particular order:
- Incorrect manual handling
- Contact with escaped contents, or from
- Impact of the cylinder, or parts of it, in the event of a sudden release of gas or explosion
Sadly the main cause of accidents involving compressed gas cylinders is human error, which can take many forms, including:
- Inadequate training
- Bad storage
- Incorrect filling or fitting of regulators and valves
- Or hidden damage caused through any combination of the above
Employers are required under law to provide safe workplaces, and to consult employees or their representatives on health and safety matters.
Important points to consider for compressed gas cylinder safety
Training. All new employees should be trained and closely supervised.
Inspection. All users of compressed gas bottles should know how to inspect the cylinder to check for damage to the cylinder itself or any external fitting. Things to look out for are dents, scorching from fire, or bulges to the body. A qualified individual should examine any cylinder showing any of these characteristics before it is used.
All new gas cylinders are made to standards set down in law and examined by an inspection body before it is used. Anyone using any gas cylinder can check this has been done correctly, and it should always be done before re-filling. The way to check is to look for a written certificate that should be with every cylinder, or a permanent mark on the body of the cylinder itself.
Repair. Don’t. It is permissible to do some work, but this should under no circumstances be undertaken by anyone who’s not qualified. That includes welding work, even if a qualified welder is to do the work. Work on cylinders must be done only by someone qualified to do that kind of hot work.
Filling. Start with the individual. Make sure they have the right PPE, including safety shoes or boots, overalls, gloves, hearing and eye protection.
- That the cylinder has been properly examined.
- That it shows no signs of damage or illicit repair (especially, make sure no grinding work has been done; this can reduce the thickness of the cylinder wall and make the cylinder unsafe.)
- That it is the right cylinder for what’s to be put in it
- All fittings are in good order and not leaking
If the checks highlight any problems on this list, filling should not take place.
After filling, check that:
- The cylinder hasn’t been overfilled
- It hasn’t been over-pressurised
- Fittings still aren’t leaking
- Wear appropriate safety clothing
- Use cylinders upright
- Fasten them securely to avoid falls
- Before use, check the contents are what you expected
- Check it’s compatible with whatever you’re connecting it to
- Fit residual pressure valves to stop anything getting into the bottle that isn’t supposed to be there
- Keep dust caps clean and re-fit them after closing valves
- Lift with cradles, hooks and slings when cranes are being used
- Fit dust caps and covers before transporting them
- Stow them upright so they can’t fall
- The driver transporting them is properly trained, knows what he’s carrying, and has the right paperwork
- Drag, roll or drop cylinders
- Store anything in them other than what they’re intended for
- Use them for anything but transporting and storing gas
- Lift them with fittings not designed for the purpose
- Lift them on a fork lift truck unless they’re secured to prevent falling off
- Let them overhang the vehicle carrying them
There are some simple rules about storing gas cylinders.
- Pick a location that’s dry, safe, flat and in the open air
- Protect gas cylinders from heat
- Keep them away from flammable materials
- Away from places where they might be knocked by other activities such as fork lift operation
- If storage must be indoors, make sure the building is well ventilated
- Use a gas cylinder cage or gas cylinder cabinet. Each has particular qualities and some unique points – but what they have in common is that they’re extremely effective for gas bottle storage in your organisation. A point to note about the cabinet over the cage is that the former is fire resistant, with different models keeping gas cylinders safe for up to 90 minutes.
The Health and Safety Executive produces an excellent guide called The Safe Use Of Gas Cylinders, The document also handily summarises the requirements of each law. Covering gas cylinders, storage and use.