That is not a gap in the module. It is a gap that lands in your documentation, at the point where you have to name what is inside the equipment you are certifying — and again later, when you want to change it.
This page sets out what each scheme does at the module layer, where a module-level route exists in the standard text, and which of those routes we have and have not been able to confirm in practice. The blanks in the table below are real blanks, not omissions.
Why the module layer is usually missing
Explosion-protection schemes were built around complete equipment placed in a hazardous area. A sensing module is not placed in a hazardous area by itself — it goes inside something that is. So the scheme’s smallest addressable object is normally the instrument, not the part.
The consequence for you is concrete rather than philosophical. When you submit for type testing, you list what the equipment contains. For each item you are asked for a manufacturer, a certificate number and an expiry date. For a sensing module, the second and third are frequently blank, because there is nothing to put in them.
There is one concept in the standards that addresses this directly, and it is worth knowing before reading the comparison.
The Ex component route, and what we could not confirm
IEC 60079-0 and its national adoptions define an Ex component: a part of Ex equipment that cannot be used on its own, is marked with the symbol “U”, and requires further consideration when incorporated into Ex equipment. The “U” suffix is appended to the component’s certificate number and indicates that the item is incomplete and not suitable for installation without further assessment.
The Chinese adoption, GB/T 3836.1—2021, carries the same definitions at clauses 3.31 and 3.65, and clause 4.2 states that Group I equipment is for coal mine methane atmospheres.
Read together, the standard text supports exactly what a module supplier would want: a component that holds its own certificate number and expiry date, in a group that covers coal mines. That is the entry your component list is asking for.
What we have not found
We have not located a Group I Ex component certificate issued to a sensing module in any scheme. A standard text that supports a route is not the same as a certifying body operating it, and we are not going to present the first as though it were the second.
If you have seen one, we would like to know — see the end of this page.
Five schemes at the module layer
| Scheme | Equipment-side route | Module-level channel | Our status |
|---|---|---|---|
| China | Safety mark (MA) + explosion-protection certificate | None. The mining product catalogue’s smallest entry under monitoring equipment is the sensor. No module, component or chip level entry exists across its 17 categories | Confirmed from the catalogue |
| ATEX (EU, Poland) | ATEX Group I M1 or M2. A worked example exists at equipment level: a Polish manufacturer holds Group I M1 Ex ia I for a 0–100 % methane analyser, certificate KDB 09 ATEX 094 | ATEX component certificate route exists in principle | Not confirmed for sensing modules |
| IECEx | IECEx Certificate of Conformity, Group I Ma or Mb | Ex Component with “U” suffix | Not confirmed for sensing modules; no Group I instance located |
| Russia / EAEU | State metrological type approval — a worked example is a drainage parameter station registered as 56528-14 — plus EAC explosion protection | Not established | Not researched |
| USA (MSHA) | 30 CFR Part 18/23 approval | Not established | Not researched. The approved products we located are 0–5 %vol ventilation class, not pipeline high-concentration |
Three of the five module-layer cells say “not confirmed” or “not researched.” Those are the honest states. A table that filled them in would be more comfortable to read and less useful to act on.
China, worked through, because the evidence there is deepest
Two findings are worth setting out, because they are specific and checkable.
The component list has columns you cannot fill
The implementation rules require a list of principal components and materials, with columns for item, name, specification, manufacturer, safety mark number (or other certificate number), expiry date, control category and remarks. Three of those depend entirely on the supplier, and two of them are the ones a module without its own certificate cannot supply.
Where this wording comes from
The wording we are citing comes from implementation rules published for other product categories. The rules specific to gas sensors were not available to us, and whether these columns are identical there is something you should verify against the rules that actually apply to your product.
Laser-based instruments have no matching product standard
The 2026 edition of the mining safety standards catalogue lists 769 standards, and a separate review of legacy industry standards lists 747. The word “laser” does not appear once in either. In practice, laser methane instruments that have reached the market cite an infrared standard together with a self-declared enterprise standard.
We state this because it describes the situation you are working in. It is not an argument that our product is more compliant than anything else — it applies to every laser-based instrument equally, including any module we supply.
What happens when you change the module later
This is the part that decides how much a supplier choice locks you in, and it is worth asking before the first order rather than after.
Chinese implementation rules list three triggers for a change application: a mandatory revision of the standard being applied; a change to an item marked with a star in the filed component list, or a change to a controlled component that does not meet its stated conditions; and a change to the product’s composition, structure, external dimensions or materials. Where a change passes final review, the safety mark number and expiry date are unaffected.
Two consequences:
- If your module’s row is starred, changing supplier or model requires a change application. Whether a gas sensing module is starred is something we have not been able to establish, and it is worth asking your certification body directly.
- Consistency is checked. The rules require that the technical parameters in the product documentation match the performance of the sample tested, and that the test sample be produced by the applying factory rather than borrowed, rented or purchased. Submitting an engineering sample and shipping a different production batch is something the consistency review looks for.
A naming trap
The control category in the safety mark component list and the key-component classification in the Chinese compulsory certification scheme use the same A/B letters for different things. They cannot be mapped onto each other.
What this means for us
We do not sell a module with a certificate attached. Given the table above, no honest supplier in this position can.
What we do instead: you tell us which route your equipment follows, and we build the component selection, the packaging and the documentation to that route’s requirements. Where a route is unresolved — three of the five cells above — we say it is unresolved rather than implying it is handled.
Concretely, for a project we prepare the inputs your submission needs: intrinsic safety parameters measured and declared, bench test reports with their conditions stated, component traceability, and the technical documentation your assessment requires. What we cannot hand you is a certificate number for a category that does not issue one.