Reviewed by the PopularGas Compliance Editorial Team — July 30, 2026. This is a procurement guide. Final cartridge selection requires the intended equipment, approved drawing or sample, test plan and destination review.
Short answer
Use nominal CO2 fill—8g, 12g, 16g, 24g, 33g, 38g, 45g, 55g, 60g, 74g, 88g or 110g—as a catalogue filter, not proof of fit. Two cartridges with the same nominal fill can have different diameter, length, water capacity, neck, thread, sealing face, puncture geometry, material, finish, tolerance, gas specification, marking and packaging.
An accurate RFQ begins with the device and interface. The buyer should send a controlled drawing, physical reference sample or complete dimensional checklist; intended application; operating conditions; gas requirement; annual volume; destination; required evidence; and packaging plan.
Why gram size is not a complete specification
The gram number normally describes nominal CO2 fill. It does not fully define the pressure receptacle or its interface.
Consider two nominal 16g cartridges. One may be threaded and designed for a specific inflator head. Another may be non-threaded and retained by a different puncture mechanism. Even when both contain the same nominal mass, they may differ in installed length, neck shape, sealing face and discharge behaviour.
The same problem appears in larger formats. A nominal 60g or 88g product can be a different construction or interface from the buyer’s reference. The words “soda maker,” “life jacket” or “airgun” are application categories, not engineering approvals.
Use size only to narrow the first conversation
The table below is a navigation aid, not a compatibility chart.
| Nominal fill | Useful first question | Do not assume |
|---|---|---|
| 8g | Is the device designed for a small pierced cartridge, and what neck profile does it require? | Beverage or appliance compatibility from 8g alone |
| 12g | Which device model, retainer and puncture geometry must the sample match? | Universal airgun or tool fit |
| 16g | Is the inflator or outdoor system threaded or non-threaded? | One common thread for every 16g product |
| 24g | What interface, installed clearance and discharge requirement control the device? | That greater fill can replace 16g without redesign |
| 33g-45g | Is the program for safety inflation, beverage, outdoor or specialty OEM equipment? | That one mid-size design covers all applications |
| 55g-74g | What water capacity, interface, gas requirement and evidence scope apply? | Food, industrial or safety suitability from size |
| 88g-110g | Is the device designed for the proposed thread, valve or cartridge envelope? | Universal refillability, thread or market compliance |
If the buyer does not know the size, send the device manual, drawing, equipment photographs and available reference cartridge. The supplier should identify the missing measurements before quoting.
Start with the intended device
Describe the system in one sentence:
We need a CO2 cartridge for [device model and function], sold in [destination], with [annual quantity], and we can provide [drawing, sample or dimensional checklist].
Then answer:
- How is the cartridge retained?
- Is it pierced, screwed into a thread or connected through a valve?
- Which component seals the interface?
- What installed diameter and length are available?
- What gas mass or functional output does the device need?
- What temperatures and storage conditions apply?
- Who validates fit and function?
- Is the cartridge non-refillable or refillable?
These questions prevent a fast but unusable quotation.
Control the interface
The interface is often the first cause of a failed sample.
Threaded designs
Record the complete thread designation, nominal diameter, pitch or threads per inch, class or tolerance, usable thread length, runout, shoulder, sealing method and gauge plan. “Threaded 16g” or “5/8 thread” is not a complete drawing.
The mating inflator, regulator or device port must use the intended thread and seal. A thread that starts by hand can still have the wrong engagement, shoulder or sealing geometry.
Non-threaded designs
Record body diameter, overall length, neck diameter, seal diameter, crown profile, puncture location, puncture thickness, hardness or material where relevant, retaining method and installed clearance.
The device’s piercing pin, gasket, retainer and gas path work as a system. Test the finished sample in the intended equipment.
Distinguish fill weight and water capacity
Nominal CO2 fill and water capacity are not the same property.
- Fill weight is the mass of CO2 specified for the product.
- Water capacity describes internal volume and can be relevant to design and regulatory thresholds.
- Gross weight includes the receptacle and its contents.
- Net gas mass supports shipping and commercial calculations.
The approved drawing and product specification should identify the values required by the chosen design and shipment route. Do not estimate water capacity from the marketing size.
Separate CO2 vapour pressure from device pressure
CO2 equilibrium vapour pressure varies strongly with temperature. It is not the same as:
- Receptacle test pressure.
- Burst-test acceptance criterion.
- Device regulator outlet pressure.
- Inflator or actuator operating pressure.
- One universal “working pressure.”
A useful RFQ states the expected temperature range and device function. The supplier should identify the product test method and limits that apply to the proposed design. The equipment designer should approve the device-side pressure requirements.
Specify the gas by application
Do not use “standard,” “high purity,” “food grade” or “medical grade” as interchangeable labels.
For each program, define:
- Intended use.
- Minimum assay if applicable.
- Impurity limits.
- Test method.
- Gas source and filling controls.
- Required specification or program.
- Batch or lot evidence.
- Change-notification requirement.
Beverage equipment may require a food or beverage-use gas specification and related handling controls. An airgun, inflator or industrial device can have a different gas requirement. A factory-wide purity statement is not a substitute for the approved order specification.
Application review: examples, not promises
Airguns and pneumatic products
12g is a common market reference, while some devices use larger threaded formats. Confirm the device model, cartridge retainer, puncture geometry, installed envelope, shot or cycle requirement and manufacturer instructions. Do not approve from a retail brand comparison alone.
Tire inflators and outdoor repair equipment
16g and 24g are common starting references, but threaded and non-threaded formats differ. Send the inflator head, target tire, required inflation result, operating temperature and packaging plan.
Life jackets, wearable inflators and safety systems
Mid-size cartridges may appear in these applications, but the complete inflator, activation mechanism, buoyancy target, applicable product standard, maintenance program and approved sample control the selection. The cartridge supplier does not certify the complete life-saving device.
Soda, coffee and beverage equipment
Equipment may use disposable cartridges, threaded cartridges or larger valve cylinders. Confirm the proprietary interface, gas specification, food-contact program, cleaning, test plan and destination. Nominal fill does not prove machine compatibility.
Outdoor and specialty OEM equipment
Identify the exact actuator, regulator, puncture system, temperature, installation and required output. Avoid using a broad application label as the technical specification.
Build a quote-ready specification
| RFQ field | What the buyer should provide |
|---|---|
| Application | Device model, function and user environment |
| Product type | Non-refillable cartridge or refillable cylinder |
| Nominal fill | Target CO2 mass and tolerance if known |
| Drawing/sample | Controlled drawing number, revision or physical reference |
| Envelope | Diameter, length, neck, shoulder and installed clearance |
| Interface | Complete thread or puncture/seal geometry |
| Material/finish | Body material, coating, corrosion and appearance requirements |
| Gas | Intended use, composition or impurity limits and evidence |
| Validation | Device test, leakage, functional output and acceptance criteria |
| Marking | Brand, model, warnings, lot/date code and languages |
| Packaging | Unit protection, count, retail pack, carton and pallet |
| Evidence | Drawing, inspection, batch, conformity and shipment documents |
| Commercial | Sample quantity, trial order, annual forecast, lead time and Incoterm |
| Destination | Countries, importer requirements and transport modes |
If a field is unknown, label it unknown rather than allowing an assumption to enter the quotation.
Approve samples before bulk price becomes final
The sample plan should compare the proposed product with the drawing or master sample and test it in the intended device.
Record:
- Sample quantity and batch.
- Drawing and device revisions.
- Measurement method and equipment.
- Critical dimensions.
- Fill and leakage results.
- Installation, puncture or thread behaviour.
- Functional output and temperature.
- Packaging used for the sample.
- Deviations and corrective action.
- Final approval signature.
If the supplier changes a dimension, material, closure, gas source, marking or process after approval, revalidate the affected requirements.
Compare supplier quotations on the same basis
A low unit price is not comparable when another quote includes a different interface, gas grade, packaging, inspection plan or shipment term.
Use a bid table:
| Comparison field | Supplier A | Supplier B | Supplier C |
|---|---|---|---|
| Drawing revision | |||
| Sample approved | |||
| Gas specification | |||
| Inspection evidence | |||
| Marking and packaging | |||
| Compliance scope | |||
| MOQ and annual capacity assumptions | |||
| Incoterm and dangerous-goods route | |||
| Change control |
Only compare price after the technical and evidence columns match.
Common sourcing mistakes
- Selecting from gram size alone.
- Assuming one thread or puncture profile is universal.
- Approving from a photograph without dimensions.
- Treating CO2 vapour pressure as the product test requirement.
- Requesting every certificate name without defining the destination.
- Treating ISO 9001 as product approval.
- Skipping device validation because a competitor cartridge looks similar.
- Forgetting dangerous-goods packaging and carrier acceptance.
- Allowing production to differ from the approved sample.
Frequently asked buyer questions
Are all 12g CO2 cartridges the same?
No. They can differ in dimensions, neck, seal, puncture geometry, material, finish, fill tolerance, marking and packaging.
Which size is best for a tire inflator?
The inflator design, thread or retainer, target tire, required gas output and operating conditions decide the product. 16g and 24g are catalogue references, not universal approvals.
Can a larger cartridge replace a smaller one?
Not without equipment review. The installed envelope, interface, gas output, regulator and safety requirements can change.
What is the fastest way to receive an accurate quotation?
Send the device model, drawing or sample, target fill, interface, annual volume, destination, packaging and evidence list.
Can PopularGas copy a reference sample?
PopularGas can review a legally supplied sample or drawing for an OEM feasibility match. The buyer remains responsible for intellectual-property rights and device approval.
Related PopularGas buyer resources
- CO2 cartridge specification center
- CO2 cartridge sample matching
- How to choose a CO2 cartridge OEM manufacturer
- Quality and compliance evidence checklist
- CO2 cartridge shipping and UN1013 checklist
- PopularGas product range
- PopularGas YouTube application videos
Send the device model, drawing or sample, target size, quantity and destination through the PopularGas contact page for a quote-ready specification review.
