A Cylinder Is Not a Roller

British Columbia's regulation lists, in one sentence, the things a compressed gas cylinder must not be subjected to: hoisted by a sling or magnet, dropped, subjected to impact, handled by the regulator, or used as a roller or work support.

Every one of those is something people do. The last two are the ones you see weekly: a cylinder laid down to roll a beam over, or stood up to prop something at a convenient height.

What the regulation actually prohibits

Section 5.38 of the BC Occupational Health and Safety Regulation sets out the handling prohibitions above, and adds that a cylinder must be secured to prevent falling or rolling during storage, transportation and use, and where practicable kept in the upright position.

Note that securing applies during use as well as storage. A cylinder standing free beside a worker because it is being used right now is not compliant and is the most common arrangement on a site.

Section 5.40 covers valves. The valve must be kept closed when the cylinder is empty or not in use, and the valve cover must be in position when the cylinder is not connected for use, unless the cylinder has an integral valve guard.

It also contains an instruction almost nobody follows: a worker must not stand directly in front of a regulator attached to a cylinder when the valve is being opened. Stand to the side of it.

And fittings must be standard components designed and manufactured for that cylinder and that gas, including provisions for flashback arresters where necessary. An adapted or improvised fitting is outside the regulation regardless of whether it holds.

Acetylene has its own rule: a cylinder containing acetylene must be used only in the upright position, because the gas is dissolved in a solvent that can be drawn out if the cylinder is laid down.

Why the cap is not optional

The valve protection cap looks like packaging and is in fact the control against the worst failure mode a cylinder has.

A high-pressure cylinder that loses its valve becomes a projectile. The escaping gas propels it with enough force to go through walls and structure, which is why the industry refers to it as a rocket cylinder.

The cap exists to stop an impact or a fall shearing the valve off. It goes on whenever the cylinder is not connected for use, which includes while moving it, while it sits in a vehicle and while it waits empty for collection.

Two handling rules follow from it. Do not lift a cylinder by the cap, because the cap is not attached to the cylinder in a way that carries its weight. And do not use a screwdriver, crowbar or any leverage device to free a stuck cap, because damaging the neck threads creates the condition you were protecting against.

Remove the cap only once the cylinder is secured in place, not before, so that nothing is standing unsecured with an exposed valve.

The 20-foot rule is narrower than people apply it

This is the correction worth taking away, because it is routinely over-applied and under-applied at the same time.

For oxygen and fuel gas, the separation is real and specific. CSA W117.2 requires oxygen cylinders to be separated from fuel gas cylinders indoors by at least 6.1 metres, or by a wall at least 1.5 metres high with a minimum half-hour fire resistance rating.

That rule exists because oxygen and a fuel gas together produce the conditions for fire or explosion if either leaks, and because oxygen dramatically accelerates combustion of anything already burning.

It does not extend to everything else. CCOHS notes that the National Fire Code does not require separation between fuel gases and inert gases, or between fuel gases and carbon dioxide, though good industry practice such as Canadian Gas Association guidance generally recommends a minimum of three metres.

So a shop storing argon next to acetylene is not breaching the 6.1 metre rule, and a shop storing oxygen three metres from acetylene is, even though most summaries treat all cylinders the same way.

Oxygen cylinders also need to be kept away from oil and grease, including on a worker's hands and gloves, because the combination is an ignition risk in its own right.

In use is not the same as in storage

The question that comes up every time someone reads the separation rule is about the welding cart with an oxygen cylinder and an acetylene cylinder strapped side by side.

The answer is that storage requirements apply when cylinders are in storage. A single cylinder of oxygen or fuel gas attached to an approved delivery system, such as a regulator or manifold, is in use rather than in storage.

So the cart is fine while the cart is the working setup. What is not fine is the cart parked in the corner at the end of the week with both cylinders still connected, which has quietly become storage without anyone deciding it had.

The practical rule is that when the job finishes, the regulators come off, the valves close, the caps go on, and the cylinders go back to their separated storage locations.

Empty cylinders have their own requirement in British Columbia: an empty cylinder must be identified as empty and stored separately from other cylinders.

Leaving a small residual pressure in an empty cylinder is standard practice, because it prevents contamination drawing back into the cylinder, and the valve stays closed regardless.

Moving them, and the vehicle problem

Transport is where the failures become serious, because an enclosed vehicle turns a slow leak into an atmosphere.

Before moving a cylinder: close the valve, remove the regulator, replace the valve protection cap hand tight, and secure the cylinder upright on a cart with a chain or strap.

Cylinders are moved by tilting and rolling on their bottom edge, not dragged, slid or rolled on their side. A cart exists for a reason and carrying one on a shoulder is how valves get struck.

In a vehicle, cylinders travel secured and upright, and the cargo area needs ventilation. A cylinder leaking in a closed van or a canopied pickup produces either an oxygen-enriched or a flammable atmosphere, and the driver is in it.

CCOHS notes that where a mobile oxygen-fuel gas welding system is assembled as a cutting, welding or heating unit, someone capable of competently operating the equipment must accompany the vehicle.

Never leave cylinders in a closed vehicle in the sun. Pressure rises with temperature, and the relief device discharging inside a van is not a situation anyone plans for.

What to wear, and what not to do with the arc

The equipment around cylinder work is the same kit as the rest of the welding and fabrication job.

Flame-resistant clothing, covered in our guide to arc rated and FR clothing under CSA Z462, with the usual caution that synthetics worn underneath can melt onto skin.

Eye protection for everything that is not the welding itself, covered in our safety glasses guide, and gloves appropriate to the handling, covered in our guide to work gloves, keeping oil and grease away from oxygen fittings.

Footwear matters because a dropped cylinder is a serious crush hazard, covered in our guide to work boots for welders, and hearing protection where the shop warrants it, covered in our hearing protection guide.

One prohibition belongs here rather than in the PPE list: never strike an arc on a cylinder, and never make a cylinder part of an electrical circuit. The arc strike damages the wall and the circuit can heat it.

And never use oxygen in place of compressed air, for cleaning, cooling or anything else. Oxygen in contact with oil or grease on clothing or skin is a fire waiting for a spark.

We do not sell cylinders, regulators, carts, restraint chains or flashback arresters. Those come from welding supply houses, and the restraint is the control this article is really about.

Setting up storage that passes

A compliant storage area is not complicated and it is rarely what people have.

Dry, well ventilated, clearly identified, not in direct sun or exposed to heat, and away from doorways, aisles, elevators and stairs so that a falling cylinder does not block an exit route.

Secure each cylinder individually rather than as a group, using chains, straps or purpose-made restraints, so that removing one does not let the others fall.

Separate by hazard class, with oxidizers kept away from flammable gases, and keep the quantity in storage as small as the operation allows.

Post no smoking signage, restrict access to trained and authorized people, and check your fire code for the requirements that apply to flammable gas quantities at your site.

Outdoors, use a fireproof surface and a tamper-proof enclosure, and protect from weather extremes rather than leaving cylinders against a fence.

For the wider programme see the complete PPE checklist for Canadian workers, our guide to PPE requirements for Canadian construction sites, our guide to who pays for PPE in Canada, our guide to CSA Z1220 first aid kit requirements and our guide to CSA certified versus CSA compliant.

Frequently Asked Questions

Can a cylinder be used to prop something up?

No. British Columbia's regulation prohibits a compressed gas cylinder being hoisted by a sling or magnet, dropped, subjected to impact, handled by the regulator, or used as a roller or work support. Cylinders must also be secured against falling or rolling during storage, transportation and use.

How far apart do oxygen and fuel gas cylinders have to be?

CSA W117.2 requires at least 6.1 metres of separation indoors, or a wall at least 1.5 metres high with a minimum half-hour fire resistance rating. That rule is specific to oxygen and fuel gases rather than applying to all cylinders.

Do inert gases need the same separation?

No. CCOHS notes the National Fire Code does not require separation between fuel gases and inert gases, or between fuel gases and carbon dioxide, although good industry practice generally recommends a minimum of three metres. The 6.1 metre rule is often applied more broadly than it needs to be.

What about the oxygen and acetylene on my welding cart?

Storage requirements apply when cylinders are in storage. A cylinder attached to an approved delivery system such as a regulator or manifold is in use. The problem arises when a cart is parked with both cylinders still connected and quietly becomes storage.

Why does the valve cap matter so much?

Because a high-pressure cylinder that loses its valve becomes a projectile with enough force to go through walls. The cap protects the valve from impact. Do not lift a cylinder by the cap, do not use a pry bar to free a stuck one, and remove it only after the cylinder is secured in place.

Is there a rule about opening the valve?

Yes, and it is widely ignored. A worker must not stand directly in front of a regulator attached to a cylinder when the valve is being opened. Stand to the side. Acetylene cylinders also must be used only in the upright position.

This guide is general workplace safety information and is not training. Compressed gas handling, storage and transport requirements are set by provincial occupational health and safety regulation, by the fire code in force in your jurisdiction, and by transport of dangerous goods legislation where cylinders travel on public roads. Confirm yours with the occupational health and safety authority that governs your workplace, and follow the gas supplier's instructions for the specific product.