What gas is used in these cartridges?

Primarily Carbon Dioxide (CO2) conforming to IS 307. (Clause 3.2)

What is the proof pressure test requirement for a cartridge?

The cartridge must withstand an internal hydrostatic pressure of 25 MPa for 2.5 minutes without any leakage or visible distortion. (Clause 6.2.1)

What is the specified burst pressure?

The cartridge must not burst when subjected to a hydrostatic pressure of less than 42.5 MPa. (Clause 6.2.2)

What markings are required on the cartridge?

It must be clearly marked with the manufacturer's name/trademark, serial number, year of manufacture, and the ISI Certification Mark. (Clause 7.1)

IS 4947

: 2006

Specification for Gas cartridges for use in fire extinguishers

CurrentFrequently UsedSpecificationFire Safety · Fire Fighting

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This standard specifies the requirements for materials, construction, performance, and testing of gas cartridges used for expelling the extinguishing medium in fire extinguishers. It ensures the safety, reliability, and interchangeability of these high-pressure components.

Specification for Gas cartridges for use in fire extinguishers

Quick Reference Values

Hydrostatic Proof Pressure Test25 MPa for 2.5 min

Minimum Burst Pressure42.5 MPa

Minimum Purity of CO299.5% v/v

Maximum Moisture Content in CO20.05% by mass

Practical Notes

Always use cartridges certified to IS 4947 within a compatible, certified fire extinguisher. Never substitute with non-standard or improperly sized cartridges.

The marking on the cartridge, including manufacturer, batch number, and test date, is a critical legal and safety requirement for traceability.

These cartridges are designed for one-time use and must be replaced after the extinguisher is discharged, even partially.