IS 309 and IS 7285: the standards for industrial oxygen in India

The five standards, and what each one covers

Oxygen is the most widely used industrial gas in India and the one with the longest chain of standards behind it. Unlike acetylene, which needs its own separate cylinder standard, oxygen sits in the mainstream: the same cylinder and valve standards cover most compressed gases.

IS 309 — the gas. The Indian Standard specification for industrial oxygen. This is the code quoted on tenders and purchase specifications, and the one an industrial customer is buying against.

IS 7285 (Part 1):2018 — the cylinder. Refillable seamless steel cylinders, normalized, 0.5 to 400 litres water capacity, covering compressed, liquefied and dissolved gases. This is the standard behind the ordinary oxygen cylinder. Part 2 covers quenched and tempered seamless steel below 1100 MPa tensile; above that, IS/ISO 9809-2 applies. Larger vessels have their own codes — IS/ISO 11120 for tubes from 150 to 3000 litres, IS 16507 for cascades.

IS 3224:2021 — the valve. The valve standard for compressed gas cylinders excluding LPG, up to 1000 litres, now in its fourth revision. It is the valve standard for industrial, medical and dissolved gases alike. Taper threads are checked against IS 7202, IS 9122 or IS 15894 depending on the form. Residual pressure valves add IS 18272:2023 on top.

IS 15975:2020 — the filling. Conditions for filling gas cylinders: charging pressure, filling ratios, minimum test pressure. This is the standard that converts a cylinder size and a pressure into a lawful quantity of gas, and it is what a filling station works to. IS 16050:2020 covers the inspection carried out at the time of filling — with acetylene explicitly excluded, which is why acetylene has its own IS 16271.

IS 8451:2018 — the retest. Periodic inspection of seamless steel cylinders, as a code of practice. Group practice is a five-year cycle for oxygen and other compressed gases, against two years for dissolved acetylene.

Above all of them sit the Gas Cylinders Rules, 2016, administered by PESO. The Indian Standards describe how; the Rules are where the legal obligation lives.

Medical oxygen is a different regime

This is the distinction that causes the most confusion, so it is set out explicitly.

Industrial oxygen is specified by IS 309, in a cylinder to IS 7285, valved to IS 3224.

Medical oxygen is a drug. It is specified by the Indian Pharmacopoeia monograph rather than IS 309, it requires a drug licence to manufacture, it is filled under a separate set of controls, and it carries a yoke-type pin-index valve to IS 3745:2024 — a physically different connection, rated at 200 bar at 15 °C, deliberately incompatible with industrial equipment.

The pin-index system exists precisely so that a cylinder cannot be connected to the wrong apparatus. That incompatibility is not an inconvenience to be engineered around with an adaptor; it is the entire safety mechanism. See medical oxygen for what we supply against it.

The oil and grease rule

Oxygen does not burn. It makes other things burn, and it does so at a violence that has no equivalent in normal experience.

In a high-pressure oxygen system, hydrocarbon contamination — oil, grease, solvent residue, a fingerprint from an oily glove — can ignite from the heat of compression alone. No spark. No external flame. Simply opening a valve quickly against a closed downstream can raise the gas temperature enough to start it. The resulting fire burns the metal of the fitting.

The practical consequences:

• Never lubricate an oxygen regulator, valve, or fitting. Not with grease, not with oil, not with PTFE tape unless it is specified for oxygen service.
• Open cylinder valves slowly, so that pressure downstream rises gradually rather than in a shock.
• Keep degreased equipment separate. Once an oxygen regulator has been used on another service or handled with oily hands, it is no longer clean.
• Do not use oxygen to blow down, ventilate, cool, or drive tools. Oxygen enrichment in a confined space turns ordinary clothing into something that burns fiercely and is very hard to put out.

Reading a cylinder correctly

Under IS 4379:1981, an industrial oxygen cylinder in India carries a black ground colour with no neck band. So does carbon dioxide — separated only by CO₂’s white or aluminium band, which fades and gets overpainted.

That shared black body is why the discipline on an oxygen cylinder is the same as on any other: the stamped marking on the shoulder, then the label, then the colour. Colour tells you where to look. The stamping tells you what it is, which standard it was built to, its working and test pressure, and when it was last requalified.

What KIGL fills against

We fill industrial oxygen against IS 309 at our Guwahati works, into cylinders built and requalified to the standards above, with the fill record and test date held against each cylinder’s individual serial number. See industrial oxygen for supply detail, and the standards index for the rest of the cluster.

These pages are not the official text. BIS holds copyright to the Indian Standards and sells the authoritative version, which is the only document that counts for compliance. Nothing here overrides the Gas Cylinders Rules, your PESO licence, or your own written procedures.