Reviewed by the PopularGas Compliance Editorial Team — July 30, 2026. This is a procurement guide, not device, transport or legal advice.
Short answer
A “12g CO2 cartridge” is not one universal engineering specification. The 12g marking describes nominal carbon-dioxide fill. OEM approval still requires the complete outside dimensions, neck or thread, sealing face, puncture geometry, material and finish, fill tolerance, gas grade, leakage and inspection method, device validation, packaging, destination and documents.
PopularGas 12g reference dimensions
| Nominal fill | 12g; tolerance by approved specification |
|---|---|
| Reference water capacity | 14 cc |
| Reference outside diameter | 18.3–18.5 mm |
| Reference length | 82.3–83 mm |
| Reference interface variants | Non-threaded or 3/8-24 UNF; confirm drawing |
These values come from the current PopularGas product catalogue and are reference values only. The approved production drawing, reference sample and device validation control the order.
Why the dimensions are not enough
Two cartridges can share a similar diameter and length and still behave differently in a device. Buyers should compare the neck profile, sealing face, puncture point, thread pitch and tolerance where applicable, shoulder geometry, installed clearance and how the cartridge is retained. A functional test in the intended device is the final compatibility check.
What “12g cartridge pressure” actually means
Several different values are often mixed together: CO2 vapour pressure at a stated temperature, cartridge test pressure, burst-test criteria, and the device’s regulated or operating pressure. They are not interchangeable.
Carbon dioxide in a filled cartridge can exist as liquid and vapour, and its equilibrium vapour pressure changes strongly with temperature. NIST publishes carbon-dioxide phase-change and vapour-pressure data. This is why a supplier should not advertise one universal “working pressure” for every cartridge and every use without stating temperature, method and scope.
For an OEM program, ask for the applicable product specification and test method. The device designer must separately confirm regulator, valve, puncture, discharge, temperature and pressure requirements.
How non-refillable cartridges are treated in standards
ISO 11118:2025 covers non-refillable metallic gas cylinders for compressed and liquefied gases within its stated scope and includes material, design, construction, inspection and manufacturing tests. The existence of this standard does not mean every 12g product is automatically “ISO certified.” Buyers should request the exact standard, product scope, test evidence, manufacturer or holder and applicable market requirements.
For shipment, classification and packaging depend on the actual product, gas, capacity, quantity, mode and route. In the United States, PHMSA’s 49 CFR framework includes provisions for limited quantities of compressed gases, but eligibility must be checked against the exact consignment.
12g OEM qualification checklist
- Identify the intended device, use and destination market.
- Provide the device drawing, cartridge drawing or physical reference sample.
- Confirm nominal fill and production tolerance.
- Approve outside diameter, length, neck or thread, sealing and puncture geometry.
- Define gas grade and any impurity or food-use requirements.
- Define leakage, fill, inspection and functional acceptance criteria.
- Validate samples in the intended device across the required temperature and use conditions.
- Approve marking, labeling, packaging and dangerous-goods shipment documents.
- Release bulk production only against the controlled specification revision.
Questions to send with an RFQ
- What equipment will use the cartridge?
- Do you have a drawing, device model or physical sample?
- Is the interface non-threaded or threaded, and what is the complete drawing?
- What gas grade, test plan and documents are required?
- What are the first order, annual volume, packaging and destination?
Primary and manufacturer sources
- NIST Chemistry WebBook — carbon dioxide phase-change data
- ISO 11118:2025 — non-refillable metallic gas cylinders
- PHMSA — 49 CFR §173.306
- PopularGas CO2 cartridge specification center
Request a model-specific 12g review and include the device, drawing or sample, annual volume, destination, packaging and evidence list.
