The Compressed Gas Cylinder Storage SOP

Purpose

A full cylinder of oxygen, acetylene or nitrogen is a pressure vessel, and in two of those three cases a fire hazard, standing on a floor where people roll carts and back trucks. This procedure guarantees that every cylinder in the shop is identified by its label, inspected before it is accepted, chained upright in the cage by type, kept apart from what it must not be near, tracked in and out, and returned or quarantined the day it is found damaged. Without it, cylinders lean against benches, empties and fulls get mixed so a tech drives to a job with an empty tank, oxygen ends up beside the acetylene, and a cylinder that tips can shear its valve. Why the storage rules are what they are, and how much a building may hold, is covered in Storing Compressed Gas Cylinders at the Shop; this is the procedure that runs every day against them.

Scope

Covers oxygen, fuel gases (acetylene, propane used for brazing and soldering), and inert gases (nitrogen, argon, carbon dioxide) in cylinders the shop receives, stores in its cage, issues to trucks and returns to the supplier. It starts when a cylinder arrives on a supplier's truck and ends when it leaves on one.

It does not cover: refrigerant and recovery cylinders, which have their own labeling, fill limits and recovery rules in Refrigerant and Recovery Cylinders in the Shop; how a cylinder rides in a truck, which is Loading the Van So Chemicals, Cylinders and Batteries Ride Safely; or setting up regulators and torches for use. A cylinder fire is not handled under this SOP at all: everyone leaves by the emergency action plan and calls 911.

Roles and responsibilities

OSHA's welding standard (29 CFR 1910.253) sets the oxygen separation and the basic storage rules for shops that use oxygen and fuel gas, and 1910.101(b) requires in-plant handling and storage of compressed gas cylinders to follow Compressed Gas Association pamphlet P-1. The local fire code (in the IFC, the compressed gases chapter, Chapter 53 in the 2021 edition, as your jurisdiction adopted it) may add limits on quantities and locations.

Procedure

1. Inspect every cylinder before accepting it, with the driver still there. For each cylinder, read the contents label, check it matches what was ordered, and look over the shell and valve. Acceptance: a legible label naming the gas, no dents, gouges, bulges, arc burns, heat or fire marks or heavy corrosion, a valve protection cap in place on cylinders built to take one, and no hiss or odor at the valve. Wrong looks like a missing, torn or unreadable label: refuse the cylinder and send it back on the truck, because in the US the color of a cylinder is not a reliable identifier of what is in it, and a gas you cannot name does not enter the building. A damaged shell or valve gets the same answer. Hazard: move cylinders only on a cylinder cart or a hand truck with a chain, never rolled on their side, dragged, or lifted by the cap.

2. Tag it FULL and write it in. Hang a FULL tag on the valve cap and write the cylinder on the cylinder log: gas, the cylinder's own number stamped or labeled on it, date received, and where it is going in the cage. Acceptance: one log line per cylinder, and the tag and log agree. Wrong looks like a cylinder you cannot find a number on: write the supplier's barcode or label number instead, and if there is nothing, that is a step 1 failure you missed. Hazard: keep the cap on while tagging; the valve is the weakest part of the cylinder.

3. Chain it upright in the cage, by type. Move it to its section of the cage (oxygen, fuel gas, inert, and an empty section), stand it upright, and chain it. Acetylene always stands valve end up. Acceptance: each cylinder is upright and individually chained, or chained in a small group where every cylinder in the group is held, with the chain above the cylinder's midpoint, fulls apart from empties, and the cage padlocked. Wrong looks like a chain at knee height that lets the top swing, or a cylinder squeezed in unchained because the section is full: stop and make room or use the next section of the same type; never leave it standing loose "for a minute." Hazard: keep one hand on the cylinder until the chain is hooked, and keep your feet out from under its base while setting it down.

4. Check the oxygen separation. Oxygen in storage is kept at least 20 feet from fuel-gas cylinders and from combustibles, especially oil and grease, or separated from them by a noncombustible barrier at least 5 feet high with a fire-resistance rating of at least one-half hour, which is the separation 1910.253(b) sets. Acceptance: you can measure 20 feet or more between the oxygen section and the fuel-gas section, or the barrier between them is in place and intact. Wrong looks like an oxygen cylinder chained in the fuel-gas section to save space, or an oily rag box beside the oxygen: move the cylinder or the box before you leave the cage. Inert gases can stand on either side. Hazard: never handle oxygen valves or fittings with oily gloves or hands.

5. Issue a cylinder to a truck or a bench. The tech signs it out on the log with the date and the truck or job. Before it leaves the cage, the regulator is off for transport and the cap is back on. Acceptance: the log shows who has it, and the cylinder rides upright and secured in the truck. Wrong looks like a cylinder carried off with the regulator still attached or no log entry: stop the tech at the door, because an unlogged cylinder is the one the weekly count cannot find. Hazard: two hands on the cart over thresholds and ramps; a full oxygen cylinder of the common sizes is heavy and top-heavy.

6. Bring empties back as empties. A returned empty has its valve closed, its cap on, and its FULL tag replaced by an EMPTY tag, and goes to the empty section. Leave a little pressure in it rather than venting it to zero, so air and moisture do not get in. Acceptance: the log shows it back, marked empty, with the date. Wrong looks like an empty set among the fulls: move it, because the next tech will load it. On supplier pickup day, count empties out against the driver's paperwork and keep the receipt. Hazard: same cart and chain rules as a full cylinder; an empty cylinder still holds pressure.

7. Respond to a damaged or leaking cylinder the moment it is found. If a valve is leaking and closing the valve hand-tight stops it, close it, tag the cylinder DO NOT USE, and call the supplier. If a fuel-gas leak cannot be stopped at the valve, get everyone away from it, keep every ignition source off (no switches, no grinding, no torches), move the cylinder outdoors away from doors, drains and people only if that can be done without passing an ignition source, and call 911 from a safe distance, then the supplier. A leaking inert gas indoors displaces oxygen, so ventilate the space and do not enter a small room where it has been leaking. Acceptance: the cylinder is outside or isolated, tagged, and the supplier has been called. Wrong looks like anyone trying to repair or tighten a cylinder valve with tools, or loading a leaking cylinder into a vehicle: stop it. Hazard: a cylinder is never moved by its valve, and a damaged one is never transported by the shop.

8. Run the weekly check every Friday. The shop lead counts the cage against the log, then walks every cylinder. Acceptance: physical count equals the log's count in and not out; every cylinder chained above its midpoint with its cap on and a FULL or EMPTY tag; the oxygen separation from step 4 intact; the cage locked; signage in place (the gas types and no smoking or open flame near the fuel gas); nothing stacked against or inside the cage that does not belong there. Wrong looks like a count that does not match: find the cylinder before the end of the day, starting with the trucks named on the log. A chain unhooked or a cap missing is fixed on the spot and written on the check. Hazard: the check is walked, not glanced at from the door, and a damaged cylinder found during it goes straight to step 7.

The record this produces

The cylinder log, kept at the cage or in the parts room: one line per cylinder with gas, cylinder number, date in, FULL or EMPTY, signed out to whom and when, date back, date returned to the supplier. Supplier delivery and pickup receipts, filed with the log, settle any dispute over cylinder rental. The Friday check sheet, signed by the shop lead, records the count, every exception and what was fixed. The owner reads the check sheet weekly and the log whenever the supplier's rental statement arrives; the fire inspector may ask to see both.

A worked pass: Monday's delivery and Friday's check

Before the delivery, the log showed the cage holding one full oxygen, one full acetylene, one full nitrogen, and three empties (one of each), six cylinders in all.

Step 1. The supplier brought two oxygen, two acetylene and one nitrogen. Four passed. The nitrogen failed: its label was torn away below the neck, leaving only gray paint and the stamped markings. The receiver refused it, the driver took it back, and purchasing reordered. The tech who needed nitrogen for a pressure test that day used the partly full cylinder already in his truck.

Steps 2 to 4. Four cylinders tagged FULL and logged by number. Oxygen chained in the oxygen section, acetylene valve end up in the fuel-gas section. The two sections sit 22 feet apart, measured with a tape, so the separation is distance, not barrier.

Step 6. The three empties went out on the same truck against the driver's receipt. The cage now held three full oxygen, three full acetylene and one full nitrogen: seven cylinders, no empties.

Step 5. On Wednesday a tech signed out one oxygen and one acetylene for a brazing job. The log showed five in the cage.

Step 8, Friday. The count found five, matching. One exception: an acetylene cylinder's chain was hooked below its midpoint after a tech had swapped cylinders on Wednesday. Re-chained on the spot and written on the check sheet. Everything else passed.

Read back against the procedure: the refused nitrogen was the right call even though the tech knew what it "probably" was, and the low chain was caught because the check is walked cylinder by cylinder.

References

• OSHA 29 CFR 1910.253, Oxygen-fuel gas welding and cutting (storage and oxygen separation); 29 CFR 1910.101, Compressed gases
• Compressed Gas Association P-1, Safe Handling of Compressed Gases in Containers (incorporated by 1910.101(b))
• International Fire Code, compressed gases chapter, in the edition your jurisdiction adopted
• See related: Storing Compressed Gas Cylinders at the Shop; Refrigerant and Recovery Cylinders in the Shop; The Cylinder That Fell in the Shop