Gas cylinders store compressed, liquefied or dissolved gas under high pressure, so how you store them on site is a legal as well as a practical matter. In the UK, gas cylinder storage is governed by the Health and Safety Executive (HSE) and set out in detail in the British Compressed Gas Association (BCGA) Codes of Practice — most notably BCGA CP44, The Storage of Gas Cylinders. This guide explains the core rules, the separation distances, and what good practice looks like, so you can store cylinders safely and stay compliant.
This article is general guidance, not legal advice. Always carry out your own risk assessment and refer to current HSE and BCGA publications for your specific gases and quantities.
Which regulations apply?
There is no single "gas cylinder storage law". Instead, several pieces of legislation combine:
- The Health and Safety at Work etc. Act 1974 — the overarching duty to store and use cylinders safely.
- COSHH 2002 (Control of Substances Hazardous to Health) — requires a risk assessment for the fire, explosion and toxic hazards cylinders present.
- DSEAR (Dangerous Substances and Explosive Atmospheres Regulations 2002) — applies to flammable gases such as LPG, acetylene and hydrogen, and requires an assessment of explosive atmospheres, particularly for any indoor storage.
- BCGA Codes of Practice — industry guidance (CP44 for cylinders, and LPG-specific codes) that the HSE recognises as good practice.
The practical starting point in every case is a risk assessment that considers the gases involved, the quantities, and the people and buildings nearby.
Do gas cylinders need to be stored outside?
Outdoor storage is the preferred method. HSE and BCGA guidance both promote a secure, well-ventilated outdoor store because good natural ventilation prevents any leaking gas from accumulating to a dangerous concentration. Cylinders should sit on a firm, level, well-drained base — concrete is ideal — and be protected from extremes of heat and from vehicle impact.
Indoor storage is not banned, but it carries more risk and triggers a DSEAR assessment for flammable gases. If cylinders must be kept indoors, the area needs proper ventilation, fire-resistant construction, and strict control of ignition sources. For most sites, a lockable outdoor cage is the simpler, safer choice.
The core storage rules
- Upright and restrained — store cylinders vertically (valve uppermost) and secure them with chains, brackets or a purpose-built rack so they cannot topple.
- Well ventilated — keep stores open to the air so any leak disperses rather than collecting.
- Secure and lockable — prevent unauthorised access and theft with a lockable cage or compound.
- Segregate by hazard — separate gases by hazard class. Flammable gases must be kept apart from oxidising gases such as oxygen, either by a distance of at least 3 metres or by a fire-resistant partition.
- Separate full from empty — store empty cylinders apart from full ones, but treat empties with the same care (they may still contain residual gas).
- No ignition sources — prohibit smoking and naked flames in and around the store.
- Clear signage — display the correct hazard warning signs and gas hazard diamonds, plus no-smoking notices.
How far should gas cylinders be stored from a building?
Separation distances depend on the gas and the quantity, but the general principle is to keep the store clear of anything that could spread a fire or trap escaping gas. As a rule of thumb, the storage area should be at least 1 to 3 metres from site boundaries, building openings (doors, windows, air intakes) and drains, with the larger distances applying as the volume of gas increases. Heavier-than-air gases such as LPG must never be stored near cellars, pits, basements or below-ground drains, because the gas can pool in low spaces. Always check the relevant BCGA or LPG code for the exact distances that apply to your installation.
What are the rules for small storage of gas cylinders?
Smaller quantities, such as a retail display or a small workshop holding, are subject to lighter but still important rules. Guidance for small storage and display indicates that no more than around five cylinders should be on a retail display, with total contents not exceeding 70kg. Single cylinders larger than 20kg should not be displayed inside shops, and where a shop sits below residential premises the quantity stored or displayed should be reduced further (no more than around 15kg). Even small quantities should be kept upright, ventilated, away from ignition sources and clearly signed.
LPG and flammable gas limits
LPG (propane and butane) is highly flammable and gets specific attention. Propane should be stored outdoors; only small amounts of butane may be kept indoors for portable appliances. HSE guidance sets quantity limits for larger stores — for example, an outdoor stack should generally not exceed 30,000kg, and indoor storage should not exceed 5,000kg in any single purpose-designed compartment. For flammable cylinders kept internally, a DSEAR assessment by a competent person is required. If in doubt, store LPG outside in a ventilated cage.
Choosing the right gas cylinder storage
For most workplaces, a gas cylinder cage or storage compound delivers compliance straightforwardly: it keeps cylinders outdoors, ventilated, upright, secure and signed in one product. Consider:
- Capacity — size the cage for your maximum cylinder count plus any empties awaiting collection.
- Segregation — use separate cages or partitions to keep flammable and oxidising gases apart.
- Restraint — choose units with chains or bars to hold cylinders upright.
- Security and siting — lockable, well away from boundaries, openings and drains, on a firm base.
Compliance checklist
- Risk assessment completed (COSHH, plus DSEAR for flammables).
- Cylinders stored outdoors where possible, ventilated, on a firm base.
- Upright and restrained against toppling.
- Flammable and oxidising gases segregated (3m or fire-resistant partition).
- Full and empty cylinders separated.
- Separation distances from boundaries, openings and drains observed.
- Ignition sources controlled; hazard and no-smoking signage displayed.
- Store secure and lockable.
Browse our gas cylinder storage cages and stands, see the wider storage cages range for security and segregation options, and explore hazardous storage cabinets for the chemicals and flammables you keep alongside your cylinders. For the official position, refer to the HSE and BCGA Codes of Practice.