SEC 04 // TAXONOMY — APPROVAL STATUS
Physical fit is not approval: how we label compatibility
A powered air-purifying respirator (PAPR) is not approved part-by-part. It is approved as a complete tested system — a specific blower, with specific filters, a specific breathing tube and specific headtops, tested together. That's how EN 12941 (loose-fitting hoods and helmets) and EN 12942 (tight-fitting masks) work in the UK/EU, how the NIOSH approval under 42 CFR 84 works in the US, and how AS/NZS 1716 works in Australia and New Zealand.
The consequence: a part can fit perfectly and still make your respirator unapproved the moment you attach it. "Will it fit?" and "am I still protected and compliant?" are different questions, and almost every parts listing on the internet answers only the first one. We label every fitment claim on this site with one of four tiers so you always know which question is being answered.
The four tiers
T1 Officially approved
The part appears on the approval documentation for the complete system: the NIOSH approval label, the CE/UKCA declaration of conformity, or the manufacturer's approval matrix. This is the gold standard — the combination has been tested and certified as protective. When in doubt, the approval label on your own unit is the final authority, because approvals are configuration-specific.
T2 Manufacturer-listed part
The manufacturer lists the part as a replacement part or accessory for the system (on an official parts list, in the user instructions, or in a parts poster). This is strong evidence, but it is not automatically the same as tier 1: some listed accessories are only approved in specific configurations — for example, a filter that may only be stacked with a gas cartridge when a particular breathing tube is used. Check the configuration constraints we note on the part page.
T3 Physically compatible — NOT approved
The part attaches, powers or fits the system — but it is not on any approval documentation. This covers rebuilt battery packs, third-party filters, and 3D-printed power-tool battery adapters. Using one voids the system's approval and the manufacturer's warranty, may remove real protections (aftermarket battery setups typically lack the OEM pack's undervoltage protection), and in a regulated workplace can put the employer in breach of OSHA 1910.134 / COSHH duties to provide approved RPE. We document these parts because welders search for them and deserve honest information — never because we endorse them.
T4 Workplace-programme context
A claim about whether a configuration is acceptable in a workplace respiratory-protection programme — the layer above the hardware. An approved system can still be the wrong choice for your exposure, required protection factor, or fit-testing regime. Where we make claims at this level, they cite the relevant regulator (HSE, OSHA, Safe Work Australia) and are general information, not advice for your workplace.
How to use these labels
- Buying a replacement consumable? Look for tier 1 or 2, then confirm against the approval label on your own unit.
- Considering a rebuild or adapter? That is tier 3 by definition. Understand what you're giving up before you decide — our decision guides spell it out.
- Responsible for RPE at work? Tiers 1–2 are the only defensible options, and tier 4 considerations (protection factor, fit, programme rules) still apply.
Our evidence rules
Every claim on this site traces to a dated source, and every source is graded: manufacturer manuals and approval labels outrank manufacturer web pages, which outrank distributor listings, which outrank forums. Where the best available evidence is only a distributor's claim — for example, a battery's backward compatibility that the manufacturer's own page doesn't mention — we say so explicitly on the part page rather than rounding up to "compatible." Records we haven't yet re-checked against a primary source carry a visible audit-supported or needs-verification badge.
Found an error or a part we've mislabelled? That matters — please tell us and we'll correct the record and log the change.