Cylinder Cart Selection Guide

A cylinder cart moves compressed-gas cylinders safely. The wrong cart tips easily, leaves the cylinder loose in transport, or puts an oxygen tank and a fuel-gas tank side by side when code says they need a barrier. Picking the right cart is about matching three things: the number and size of cylinders you move, the surface you move them across, and whether your operation requires a firewall barrier between oxygen and fuel-gas.

This guide covers the five cart archetypes you will see on a welding shop floor, a gas distributor’s dock, a fire-department bay, and a medical-gas supply chain: dual-cylinder oxy/acetylene carts, firewall carts, single-cylinder dollies, propane carts, and multi-cylinder trailers. For each, we cover when to use it, where it falls short, and which Saf-T-Cart models fit.

You will hear cylinder carts called a lot of different things on the shop floor. A two-bottle frame for an oxy-acetylene rig is called a welding cart, a torch cart, a cutting torch cart, or a torch bottle cart. A single-cylinder upright is a cylinder dolly, sometimes a torch dolly when used with a welding cylinder. Cutting torch trolley is the British and Australian phrasing for the same equipment, and a cutting torch kit usually means a torch, regulators and hoses packaged together, sometimes with a cart. The names change, the hardware doesn’t. Pick the cart that matches your cylinder count, cylinder size, and whether code requires a firewall barrier.

The most important code reference for cylinder carts is OSHA 29 CFR 1910.253(b)(4)(iii), the oxygen / fuel-gas separation rule. The regulation reads:

The rule applies to cylinders in storage, and OSHA has said when a pair on a cart is not in storage. In a shop (general industry), a single oxygen and acetylene pair connected to properly working regulators is in use, however long it sits between uses. On a construction site, OSHA applies a 24-hour test: the pair is in storage when gas will not be drawn within 24 hours. And OSHA treats a single oxygen-and-acetylene pair on a purpose-built cart as de minimis (not cited) only when the cart is designed to hold both cylinders upright, both cylinders are securely held, the cart is on a firm, level surface outside areas where vehicles, equipment or materials could reasonably strike it, and both cylinders either have their valves closed with protection caps on or are connected to properly functioning regulators. The details and OSHA's letters are in our gas cylinder storage guide.

When the cylinders are in storage, there are two ways to comply:

• Keep the oxygen and fuel-gas cylinders 20 feet apart, each on its own dolly or rack
• Use a firewall cart whose barrier between the oxygen and fuel-gas cylinders is noncombustible, at least 5 feet high, rated for at least half an hour and designed to keep a fire from spreading between them

A firewall cart is the simpler path when a pair will sit on the cart in storage: a construction crew that leaves the rig untouched for days, or a cart that does not meet the safe-harbor conditions. Two single dollies cost less up front but mean committing to separated storage every time. State-plan OSHA rules and local fire codes can add requirements.

Related standards

• NFPA 55, Compressed Gases and Cryogenic Fluids Code — facility-level storage, labeling, and ventilation requirements
• CGA P-1, Safe Handling of Compressed Gases in Containers — industry best practice from the Compressed Gas Association
• DOT 49 CFR Parts 173 and 177: hazmat packaging and highway transport rules for compressed-gas cylinders, including how cylinders are secured on a vehicle

A two-cylinder cart, firewall or not, is rated by the widest cylinder each side will hold. The rating is two numbers, oxygen first. A cart rated 9-1/2 in and 12-1/2 in takes an oxygen cylinder up to 9-1/2 in across and a fuel-gas cylinder up to 12-1/2 in across. Match your cylinders to that pair. Not to the gas volume on the tag, and not to a number in the cart’s model name.

Step 1: Read the tag, then measure

The tag or label from your gas supplier gives the capacity in cubic feet, for example “300 CU FT”. The chart in step 2 shows the usual diameter for that size. Treat it as a starting point:

• The cubic feet is how much gas the supplier put in, not how big the steel is. A cylinder its maker rates at 397 cu ft can arrive labeled about 323.
• The cylinder is usually stamped on the shoulder or neck with a specification such as DOT-8 or DOT-8AL on acetylene, or DOT-3AA or DOT-3AL on oxygen. DOT-8 and DOT-8AL acetylene cylinders also carry a tare-weight marking. None of those marks is a diameter.
• Some cylinders break the pattern. One acetylene cylinder rated about 324 cu ft is 9 in across and 65 in tall, against about 12 in for the usual 300 to 340 size.

Then measure:

• Measure straight across the middle of the body. Not across the cap, the valve guard or the foot ring at the bottom.
• No calipers? Wrap a tape around the body and divide by 3.14. About 29 in around is 9-1/4 in across. About 38-1/2 in around is 12-1/4 in across.
• If an acetylene cylinder reads over 12-1/2 in, measure again at the middle of the body. Every standard acetylene size in the chart below is under 12-1/2 in. For oxygen, every size in the chart is under 9-1/2 in, though some larger high-capacity cylinders are wider and need a wider cart.

Step 2: Find your size in the chart

Acetylene cylinders

Oxygen cylinders

The valve adds about 4 in to an oxygen cylinder’s height, and the cap more.

Figures are rounded from cylinder makers’ and gas suppliers’ published spec sheets. Diameters vary a little by maker, and size names (#4, Size 5, WK and so on) vary a lot by supplier, so go by the diameter. These are the common sizes, not every cylinder made.

Step 3: Pick the cart

• Each cylinder has to be at or under the rating for its own side. The oxygen side is usually the narrower one.
• The common full-size pair, a 9-1/4 in oxygen cylinder and a 12 in acetylene cylinder, fits a cart rated 9-1/2 in and 12-1/2 in.
• Too small is a problem too. Some carts hold each cylinder in a fixed clamp or ring sized for a full-size cylinder, and a smaller one sits loose in it. For example, an acetylene cylinder of about 8 in in a clamp built for 12 in. Some makers build the same cart with smaller clamps, and a cart that uses a chain can be pulled tight on a smaller cylinder. If yours falls between sizes, ask before you order.
• A short cylinder can sit below a fixed clamp. Check height as well as diameter when the cart’s clamps are at set heights.
• Large propane and propylene cylinders are wider than acetylene. A standard oxy-acetylene cart will not take a 100 lb propane cylinder; carts for those are built or widened for them (on Saf-T-Cart carts, the -P builds).
• Firewall carts are tall: a firewall used as the OSHA storage barrier has to be at least 5 ft high. Check the cart’s overall height against doorways and overhead clearance on the route.

A firewall cart puts a barrier between the cylinders. For cylinders in storage, OSHA 1910.253(b)(4)(iii) sets what that barrier must be; see Firewall & OSHA above.

Other cylinders

• Propane: squat DOT cylinders with their own geometry. Use a cart built for propane.
• Medical: E, D and M cylinders are narrower than industrial welding cylinders, and a welding cart leaves them loose in the strap. Use a cart or stand sized for medical cylinders.
• Specialty: calibration gas, ultra-high-purity and fire-service air cylinders have their own diameters. Check the cart’s cylinder rating.

Wheel selection is the detail that decides whether a cart rolls smoothly across your floor or fights you every ten feet. Match the wheel to the surface.

Saf-T-Cart fits the wheel to the job. The 401-14FW rolls on 14 in semi-pneumatic flat-free wheels, a shop-floor compromise. Jobsite carts such as the 402-16 and the 552-16FW ride on 16 in pneumatic tires. The 503-20 and 403-20FW use 20 in steel wheels, which Saf-T-Cart says keep the cart flat free however much abuse it takes, and the 504-30 and 554-30 carry large auto or trailer tires for construction sites and rough terrain. If your facility is all-indoor polished concrete, solid rubber rolls quieter.

Saf-T-Cart is a cylinder cart manufacturer based in Clarksdale, Mississippi. Its line covers propane, oxygen, and acetylene carts, dollies, stands, cradles, cages, and trailers.

Saf-T-Cart models by family

• Small and medium two-cylinder carts: the 810-6 and the 820, 935 and 950 series
• Large two-cylinder carts: the 401-14, 402-16, 860-14 and 870-14
• Heavy jobsite carts: the 502-16 with a toolbox, the 503-20 on steel wheels, the 504-30 and 554-30 on auto or trailer tires, the 552-16 and hooded 552-16H with a lifting eye, and the 1324 IIE with a lockable cabinet for the regulators and torches
• Firewall carts (FW): those frames with a steel barrier between the cylinders, from the narrow 601-10FW to the 554-30FW
• Propane builds (-P): 400 and 500 series carts widened for a 100 lb propane or 115 lb propylene cylinder
• Single-cylinder carts: the 750-10, the 900-10-8 and the 250 series

A cylinder cart is a piece of life-safety equipment. Inspect it on the same cadence you inspect the cylinders it carries.

Pre-use inspection (before every move)

• Chain, strap or clamp holds the cylinder securely, so it cannot tip or fall off the cart
• Wheels spin freely, no flats or wobble on the axle
• Frame welds show no cracks or deformation
• Firewall (if equipped) is straight, not warped or pierced
• Valve-protection caps on when the cylinders are not connected for use. If the regulators stay on for an in-plant move, use a cart built to hold the cylinders upright and protect the valves and regulators

Periodic maintenance

• Replace worn chains and straps — do not splice or weld-repair a cylinder retention strap
• Repack or replace wheel bearings if the cart is rolling rough
• Repaint or treat rust spots to keep the frame sound
• Retire the cart if the frame is bent, cracked, or the firewall is compromised