How to read a refrigerant cylinder label
The product markings
The designation. R-22, R-410A, R-134a and so on, stencilled or on the label. If a cylinder only says refrigerant or carries a trade name with no R-number anywhere, that is a problem, not a style choice.
The brand. On the cylinders we supply this is Stallion or Refron. The brand is what conformity attaches to, because the manufacturer is the party that tested the fill.
The batch or lot number. The link between the cylinder in front of you and the manufacturer's documentation. Without it, a data sheet is a general document about a product rather than evidence about your cylinder.
Net weight. The mass of refrigerant, as distinct from the mass of the cylinder.
The cylinder markings
These are stamped into the metal, usually on the collar or neck ring, and they describe the container rather than the contents. You will find the manufacturer's mark, the specification the cylinder was built to, the test pressure, the water capacity, the tare weight and a date.
The date is the periodic hydrostatic test. A refillable cylinder must be retested at intervals, and a cylinder past its test date should not be refilled. On the R-508B cylinders in our stock the test collar is clearly visible above the shoulder, which is typical for that format.
Tare weight matters more than it looks. Gross weight minus tare is how you check a cylinder actually contains what the label says, and short-filling is one of the commoner frauds in this trade.
Colour tells you nothing reliable
Refrigerants used to be colour-coded, and plenty of people still read them that way. R-22 green, R-410A rose, R-134a light blue. AHRI Guideline N moved to a single grey-green for all refrigerant cylinders from 2020, precisely because colour was being trusted as identification when it never carried a specification behind it.
You will still see old colours in the field, because cylinders last a long time. Read the label and the stamping, not the paint.
What a suspect cylinder looks like
No batch number. A label printed on paper and taped on rather than applied as a proper product label. A designation that does not match the valve type for that gas. Weights that do not add up when you put the cylinder on a scale. Repainting over an old marking, which is prohibited under the Gas Cylinders Rules for good reason. Any one of these is worth a question before you connect it to a compressor.
Quick answers
What is the tare weight on a cylinder?
The weight of the empty cylinder with its valve. Subtract it from the gross weight to check how much refrigerant is actually inside.
Do refrigerant cylinder colours still identify the gas?
No. AHRI Guideline N moved all refrigerant cylinders to a single grey-green from 2020. Colour is not identification. Read the designation and the label.
What does the date stamped on the collar mean?
It records the periodic hydrostatic test. A refillable cylinder must be retested at intervals and should not be refilled once it is past due.
Why does the batch number matter?
It ties the cylinder to the manufacturer's documentation for that fill. Without it, a data sheet is a general product document rather than evidence about the cylinder you hold.
- Gas Cylinders Rules, 2016 · marking, periodic testing and prohibition on repainting over markings · peso.gov.in.
- AHRI Guideline N · refrigerant cylinder colour standardisation · ahrinet.org.
- AHRI Standard 700 · specifications for refrigerants · ahrinet.org.
This guide is general information compiled from the cited sources — not legal, safety or engineering advice. Read our full disclaimer.
Related: Cylinder colour codes · Genuine vs counterfeit · COA and traceability · Storage safety