Skip to content 
For gas cylinders, DOT certification is mandatory for the U.S. market, while TPED (π mark) is essential for transportation within the EU. CE alone is not sufficient for refillable or transportable pressure equipment. Importers who misunderstand this often face customs holds or transport bans.
Our Factory Summary
We manufacture gas cylinders on five production lines and ship regularly to Europe and the United States.
In 2024 alone, we assisted multiple distributors who failed EU transport inspections because their cylinders had CE marking but no TPED approval. In three cases, the products were technically safe, but still illegal to transport.
This article exists because too many buyers still confuse product safety with transport legality.
Which Certifications Actually Matter (And Which Don’t)
From a factory perspective, certifications fall into two very different categories:
Which Certifications Actually Matter (And Which Don’t)
These determine whether your cylinders can legally enter and circulate in a market.
2. Manufacturing System Certifications (Supporting role)
These show factory capability but do not replace legal compliance.
Most importers fail because they mix these two together.
DOT Certification — Mandatory for the United States
If you sell or refill gas cylinders in the U.S., DOT is not optional.
From our production records, all DOT cylinders must meet:
Specific alloy requirements (commonly aluminum 6061)
Controlled wall thickness tolerance
Hydrostatic testing
Burst pressure testing
Traceable serial numbers
For paintball and beverage distributors, this is especially critical. We often advise buyers to review real DOT-compliant tank structures, such as those outlined in our HPA paintball cylinder specifications, because these show what U.S. compliance actually looks like in production—not just on paper.
Factory insight:
Some low-cost suppliers reuse DOT numbers across batches. This is one of the fastest ways to get permanently flagged by U.S. customs.
TPED (π Mark) — The Most Misunderstood Certification in Europe
Here is the uncomfortable truth most sellers won’t tell you:
CE marking alone does NOT allow gas cylinders to be transported in Europe.
For refillable or transportable cylinders, TPED approval is required. Without it:
Road transport is illegal
Logistics companies may refuse the shipment
Insurance coverage may be void
We’ve seen cylinders pass internal safety tests but still fail EU transport checks because they lacked TPED documentation.
If you want a neutral explanation of how TPED fits into European pressure equipment regulation, the Transportable Pressure Equipment framework explained on Wikipedia helps clarify why CE and TPED are not interchangeable.
Factory “black material”:
In 2024, two EU customers failed TPED audits because their supplier outsourced testing but could not provide batch-level traceability. TPED inspectors do not accept “factory statements.” They require real records.
ISO Certification — Useful, but Often Overestimated
ISO certifications (such as ISO 9001) prove that a factory has a structured management system.
They do not guarantee:
Cylinder safety
Pressure performance
Legal market access
From our experience, ISO is best treated as a baseline filter, not a deciding factor.
Many trading companies have ISO certificates.
Very few can pass DOT or TPED audits.
Certification Comparison Table (Factory Use Version)
| Certification | Region | Purpose | Factory Reality |
|---|---|---|---|
| DOT | United States | Legal sale & refill | Mandatory |
| TPED (π) | European Union | Legal transport | Mandatory |
| CE | EU (general products) | Product conformity | Insufficient alone |
| ISO 9001 | Global | Management system | Supportive only |
Factory Process — How We Prepare Cylinders for Certification
Certifications are not “documents.” They are the result of repeatable processes.
Step-by-step from our factory:
Material verification — alloy batch chemical analysis
Forming & heat treatment — controlled furnace zones
Thread machining — calibrated CNC tools
Hydrostatic testing — batch-based, recorded
Burst testing — sample destruction, logged
Serial number assignment — batch traceability
Certification file assembly — test + production records
Any factory that skips one of these steps cannot support real certification audits.
Common Buyer Mistakes We See Every Year
Believing CE = TPED
Accepting scanned certificates without verification
Buying “DOT-style” cylinders instead of real DOT cylinders
Ignoring batch traceability
Trusting traders who outsource everything
These mistakes are not theoretical. They come from real failed shipments.
Direct Answers
Q: Is CE enough for CO2 cylinders in Europe?
No. CE alone is not sufficient for transportable pressure equipment. TPED is required.
Q: Can ISO replace DOT or TPED?
No. ISO only proves management capability, not legal compliance.
Q: Why do some cheaper suppliers still sell to Europe or the U.S.?
Because enforcement happens at transport or refill stage, not always at sale.
Clear Conclusion — Factory Recommendation
If you are importing gas cylinders:
U.S. market → DOT is mandatory
EU transport → TPED is mandatory
ISO is helpful but never sufficient
If a supplier cannot explain how certification connects to their actual production process, they do not truly understand compliance.
That is the line between a factory and a seller.
