Propane Is Everywhere in Your Shop — and 1910.110 Has Opinions About Where You Put It

Propane arrives in a small business quietly. A forklift comes with two spare tanks. Someone buys a torch kit. The shop adds a construction heater for the winter and a grill for the summer cookout. Nobody ever decided to store hundreds of pounds of flammable gas on the property — it accumulated, one cylinder at a time. And because propane feels ordinary, the cylinders end up wherever there's floor space: the back corner of the warehouse, a closet near the loading door, the shelf under the workbench.

That accumulation is regulated in detail. 29 CFR 1910.110 covers the storage and handling of liquefied petroleum gases, and unlike most standards, it works largely by incorporating NFPA 58 by reference. The result is a rule that is more specific about quantities and distances than almost anything else in Subpart H, and one that small employers rarely read until an inspector opens a storage room door.

The Indoor Limits Are Lower Than You Think

The single most useful thing to know from 1910.110 lives in paragraph (f), which governs containers in storage — cylinders that are full or partially full but not connected for use.

Inside a building frequented by the public, individual containers are limited to 20 pounds of propane capacity. That's the standard grill bottle, and it is a hard ceiling. If your business has a retail counter, a showroom, a waiting area, or any space customers walk through, a 33-pound forklift tank does not belong on that side of the wall.

Inside a building not frequented by the public — a warehouse, a shop floor, an industrial space — the aggregate limit is 300 pounds of propane. Aggregate is the word that catches people. It isn't 300 pounds per room or per rack; it's the total sitting in that building. Six full 43.5-pound forklift cylinders will exceed it. So will a modest stack of 100-pound heater bottles left over from January.

Cylinders in storage also have to be positioned so the pressure relief valve is in direct contact with the vapor space, which in practice means upright and secured. A cylinder lying on its side can discharge liquid propane through the relief valve instead of vapor, and liquid expands roughly 270 times as it boils off. That's the difference between a hiss and a fire.

Outside Is the Answer, but Not Anywhere Outside

The compliant fix for most shops is simple: move storage outdoors. Paragraph (f)(5) sets separation distances from the nearest important building and from the line of adjoining property that may be built upon, scaled to the aggregate quantity stored. Small aggregates — 720 pounds or less — may generally sit against the building, while larger quantities push the required separation out to ten feet and beyond.

Outdoor storage still needs structure. Cylinders should sit on a firm, non-combustible surface, be protected from vehicle impact, be secured against tipping, and be kept clear of exits, stairways, and egress paths. A ventilated cage or a bollarded rack with a chain restraint satisfies most of this and costs less than a single citation.

If your work is construction rather than general industry, note that 29 CFR 1926.153 applies instead, and it is blunter: storage of LP-Gas within buildings is prohibited. There is no 300-pound allowance on a jobsite. Temporary heaters and their fuel supply are addressed separately in 1926.154, including requirements for stability, clearance from combustibles, and ventilation when heaters run in enclosed spaces.

The Habits That Matter More Than the Table

Most propane incidents at small businesses don't trace back to a distance table. They trace back to routine.

Forklift cylinder changes deserve their own short procedure. Section 1910.178(f) ties powered industrial truck fuel handling back to 1910.110, and the practical rules are consistent: change tanks outdoors or in a well-ventilated area, shut the engine off first, wear gloves against the cold-burn risk from escaping liquid, confirm the locating pin seats correctly, and leak-check the connection with soapy water rather than a flame. Never refill a cylinder while an engine is running.

Cylinders themselves age out. DOT cylinders require requalification twelve years after manufacture and periodically thereafter, and vertical cylinders between four and forty pounds need an overfill prevention device. Exchange suppliers refuse out-of-date or damaged bottles, so expired ones tend to sit in the corner indefinitely. Build a quarterly walk that stages them for return.

Finally, propane is a hazardous chemical under 1910.1200. It needs a safety data sheet in your collection, and employees who handle it need to know the hazards — including that propane vapor is heavier than air and will pool in pits, trenches, floor drains, and basements rather than dissipating upward.

A Twenty-Minute Audit

Walk the property once with a clipboard. Count every cylinder, note its size and location, and total the pounds sitting inside each building. Check that every stored cylinder is upright and restrained, that none block an exit, and that connected cylinders have caps or plugs on the ones that aren't. Add the outdoor storage location to your fire prevention plan under 1910.39, and make sure the local fire department knows where it is.

Most shops find they're over the indoor limit, and most fix it in an afternoon with a rack, a chain, and a padlock — a rare kind of compliance problem where the correct answer is cheap, permanent, and genuinely reduces the chance of a very bad day.