Standards · IS 1090:2002 · IS 7285 (Part 1):2018 · IS 3224:2021
IS 1090: the Indian Standard for compressed hydrogen and how it is handled
Compressed hydrogen in India is specified by IS 1090:2002. It is filled into seamless steel cylinders to IS 7285 Part 1, valved to IS 3224 with a left-hand thread, painted signal red shade 537 under IS 4379 with no neck band, and requalified every 5 years under IS 8451.
- Gas specification
- IS 1090:2002
- Cylinder construction
- IS 7285
- Cylinder identification
- Signal red
- Valve thread
- Left-hand
- Periodic retest
- Every 5 years
What IS 1090 covers
IS 1090:2002, Compressed Hydrogen, is the Indian Standard specifying hydrogen as a product. As with every gas, it covers the gas itself — the cylinder, valve, colour and retest interval each come from their own standard.
| Standard | What it governs |
|---|---|
| IS 1090 | The gas |
| IS 7285 (Part 1) | The seamless steel cylinder |
| IS 3224 | The valve — left-hand thread, as for every fuel gas |
| IS 4379 | Signal red, shade 537, no band |
| IS 8451 | Five-yearly hydrostatic retest |
The left-hand thread
Hydrogen is a fuel gas, and fuel-gas fittings use a left-hand thread, usually with a notch cut into the nut so it can be recognised by hand as well as by eye.
It is there for one reason: so that a fuel regulator cannot be fitted to an oxidising gas, or the reverse, by somebody working quickly at the end of a shift. If a fitting will not start, that is the system working. Never force it, and never use an adaptor to make one thread meet another.
Why hydrogen leaks behave unusually
Three properties make a hydrogen leak harder to detect than any other gas in the range, and all three should shape how a hydrogen area is laid out.
The flame is nearly invisible in daylight. A hydrogen leak can be alight with nothing to see — no yellow flame, no smoke. It is a documented cause of injury, because the flame is found by walking into it.
It is the lightest gas there is. It rises immediately and collects at ceiling level rather than dispersing at working height. Ventilation at the top of the room is not optional, and a gas detector at waist height will not find it.
Its ignition energy is very low. A static discharge from clothing is sufficient. Bonding, earthing and antistatic discipline are not precautions borrowed from other gases; they are the ones that matter here.
Signal red means fuel gas, not hydrogen
Under IS 4379, hydrogen is signal red, shade 537, with no neck band. But LPG, methane, propane and butane are also signal red.
So the colour identifies the cylinder as a fuel gas rather than as hydrogen specifically. That is a useful thing to know at a distance and a dangerous thing to rely on up close. The stamped marking on the shoulder tells you which fuel gas you actually have — read it before connecting a regulator that may be rated for something else.
What KIGL does with hydrogen
We supply hydrogen. The hydrogen product page says supply throughout and makes no manufacturing claim, and this page follows it.
That distinction is worth pressing any supplier on. A company that is vague about which gases it manufactures and which it buys in is a company worth asking harder questions of, because the answer determines lead time, security of supply, and who is accountable when a batch is wrong. Ask us about any gas in the range and you will get a straight answer.
Full hazard data is in the hydrogen safety data sheet, and fuel-gas lines need flashback arrestors at every take-off.
IS 1090 — frequently asked questions
Which Indian Standard specifies hydrogen?
IS 1090:2002, titled Compressed Hydrogen, reaffirmed since. It specifies the gas itself. The cylinder, the valve, the colour and the retest interval each come from their own standard, which is the pattern across every gas — one specification for the product, four more for what it arrives in.
Why is the valve thread left-handed?
Because hydrogen is a fuel gas, and the convention across fuel gases is a left-hand thread — often marked with a notch cut into the nut. It exists so that a fuel regulator cannot be fitted to an oxidising gas, or the reverse, by someone working quickly. If a fitting will not start, that is the system telling you something. Never force it and never use an adaptor.
What makes a hydrogen leak different from other gas leaks?
Three things, all of which make it harder to detect. Hydrogen burns with a flame that is nearly invisible in daylight, so a leak can be alight without anything being visible. It is the lightest gas there is, so it rises and collects at ceiling level rather than dispersing at working height. And its ignition energy is very low — a static discharge is enough.
What colour is a hydrogen cylinder in India?
Signal red, shade 537 under IS 4379, with no neck band. Note that LPG, methane, propane and butane share the same signal red, so the colour identifies the cylinder as a fuel gas rather than as hydrogen specifically. The stamped marking on the shoulder is what tells you which fuel gas you have.
Does KIGL manufacture hydrogen?
We supply it. The page for the product says supply throughout and makes no manufacturing claim, which is deliberate — a supplier who is vague about which gases it makes and which it buys is a supplier worth asking harder questions of. Ask us directly and you will get a straight answer for any gas in the range.
How often must a hydrogen cylinder be retested?
Every five years, hydrostatically, to IS 8451:2018 — as with the other compressed gases. Dissolved acetylene is the exception at two years, under IS 8433, because of its porous mass and solvent.
Enquiries
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