A gas cylinder in a fire is basically a bomb, and the fire brigade treats it that way. If your premises has gas cylinders and there is a fire, a hazard zone will be put around your premises, with a 200 meter cordon used for a fire involving acetylene cylinders, and your building will be left to cool for hours before anyone can go back in. This should help you understand the storage of gas cylinders, because it puts the question into a different context. The primary concern is not the protection of the gas cylinders. It is the protection of the premises and the people in the premises to make sure that when something else goes wrong, the gas cylinders do not turn what is already a serious situation into the worst case scenario of an evacuation.
Gas cylinders are also a risk in their own right when they are stored in a place that doesn’t have adequate protection. They are heavy, top-heavy and if they fall, they can shatter their own valve. They can injure people without even being involved in a fire.
General practices for cylinder storage
It is important to have signage in place, even if it appears to be a minor detail. The signage exists for the fire brigade to know what is on site, and this is the reason for the immobilization of storage structures in the yard.
Cages
Most people design outdoor storage as a cylinder cage. A typical build of a cylinder cage is a galvanised steel mesh with a locking door and an optional roof. The mesh design helps with ventilation and helps drain the cage if something were to leak. The galvanising helps the cages last while being outdoors. It’s especially important for the valves and regulators to be protected from the elements. The cages also need to be bolted down to the ground to secure them and to prevent the cage from being blown away. The boundary rules take precedence over where the cage is positioned, which is also important to note. The cage should be positioned to conform to the rules and within reach of the forklift.
The cage should definitely be locked. Cages that are not secure get tampered with and stolen. Empty cages are also stolen for scrap. Some cages have space in the base to help with fork-lifting the cage. This is useful for sites that transport gas cylinders.
Adding racks to the interior of the cage helps secure the gas cylinders, and stops them from moving around as the cage is transported.
Indoor Storage and Fire-Rated Cabinets
It is becoming increasingly common to have gases indoors (lab gases, small cylinders that feed fixed equipment, calibration gas, etc.). The indoor storage of gases comes with stricter rules. These rules cover storage in minimum quantities, adequate ventilation, and in most cases, a gas cylinder cabinet where larger quantities are concerned. 90-minute cabinets are designed to allow enough time for evacuation and for the fire brigade to respond, similar to lithium cabinets. The cabinet is designed to allow good ventilation to avoid the trapping of leaks. The cabinet would be designed to allow venting of the leak. the risk assessor and the insurance company would want to see the certification, as would battery cabinets. Just because a cabinet looks right, doesn’t mean it meets the standards. There is a saying that if a gas cylinder can live outside, it can live outside. Indoor storage should be reserved for the gas cylinders that truly cannot be stored outside.
Moving Cylinders
Moving gas cylinders is even less safe than storing them, and causes more injuries. The right way to move gas cylinders is with a purpose-built trolley that straps or chains them in place. Cylinders should NEVER be rolled along their bottom edge. This is a practice that is far too common. Caps should remain on cylinders during transport. Cylinders should always be stored upright during transport. Moveable gas cylinders should also be stored upright due to the special case of acetylene. It should remain stored upright for a period of time before it can be used after being laid down. For sites that move gas cylinders frequently, a gas cylinder trolley is as important as a drum dolly. They are inexpensive, unglamorous, and completely eliminate a manual handling injury.
The regulations behind it
DSEAR is the primary regulation framework — if looking at flammable gases as dangerous substances where containment amounts, separation distance, and ignition control are determined by DSEAR RA, BCGA (British Compressed Gases Association) documents and codes of practice provide the detail where the quantities of gas, separation distance, and compound design are articulated. BCGA is the go to reference when designing and building a cylinder store and when gas safety is a design consideration alongside the guidance paragraphs on dangerous gas storage on HSE’s gas safety pages (https://www.hse.gov.uk/gas/). It’s also a requirement that designed stores are included in the premises fire risk assessment, and it’s one of the first things the fire brigade will ask about.
For the bigger picture of storage, particularly lithium batteries, which use much of the fire logic, see [→ our fire safety and hazardous storage guide].