Can Classic Filters housings be used in ATEX zones?

We get asked this a lot: can Classic Filters housings be used in an ATEX zone? For the stainless steel series listed on our ATEX declaration, the answer is yes. You can use them in Zone 1 (gas) and Zone 21 (dust), which is Group II Category 2, as long as qualified people install them and you mount them where nothing can impact them.

What they do not need is an ATEX certificate or an Ex mark. That sounds the wrong way round until you look at what the directive actually covers.

What ATEX is actually checking

ATEX directive 2014/34/EU covers equipment intended for use in potentially explosive atmospheres. It applies to electrical equipment, and it also applies to non-electrical equipment if that equipment has its own source of ignition. A motor, a switch, a hot surface or a pair of moving parts that can spark all count.

A 316L stainless steel filter housing is a pressure vessel with a filter element inside it. There is no motor, no switch and no rubbing parts. After an ignition hazard assessment to EN ISO 80079-36:2016, our listed housings contain no source of ignition. Products like that sit outside the scope of 2014/34/EU. The directive itself says many simple mechanical products fall outside it for exactly this reason.

So our declaration document is not an ATEX certificate. It is confirmation that we have carried out the assessment, the housings have no ignition source, and you can use them in a Group II Category 2 area. That is CS05, our ATEX Directive (2014/34/EU) Declaration.

Zone 1 and Zone 21, in plain terms

An explosive gas atmosphere is likely in normal operation in Zone 1. Combustible dust works the same way in Zone 21. Both map to Group II Category 2 equipment. That is the environment our declaration covers.

Two conditions come with it:

• Qualified personnel must install the housing.
• Mount it where impact cannot occur.

A damaged filter housing is no longer the product we assessed. Keep it out of fork-truck and swinging-load paths, and treat the rest of the system (valves, regulators etc.) under their own ATEX files. The filter housing does not make those items safe.

Which housings the declaration covers

CS05a covers these filter housing series for Zone 1 and 21:

• SG111, SS112, SS117, SV117, SS119
• SiS117, SiS127, SiS119, SiS129, SiS147
• SG121, SS127, SS125, SV127, SS147
• SS129, SS1210, SS1211, SG211, SS212
• SS215, SiS215, SV215, SS216, SiS216
• SS218, SiS218, SS219, SiS219, SG231
• SS232, SS235, SiS235, SV235, SS236
• SiS236, SS238, SiS238, SS239, SiS239

If your series is not on that list, ask us. We hold further ATEX declarations for other housings, and we can check a special against the same EN ISO 80079-36 method.

We have attached the ATEX Directive (2014/34/EU) Declaration (CS05 Issue 3) to this post. When the rest of the ATEX files are on the site they will also sit on our certificates page with the PED and UKCA files.

ATEX is not the same as a CE mark

People often mix the two. The CE mark on our housings is for the Pressure Equipment Directive 2014/68/EU, not for ATEX. Above the PED thresholds the housing needs a CE mark and a PED declaration of conformity. Below those thresholds we build it to sound engineering practice and do not CE-mark it. We have Module H approval, so we can CE-mark standard housings and one-off specials. We wrote that up in what are CE marks?

ATEX is a different question: is there an ignition source? For these housings, no. You can therefore have a CE-marked, NACE-compliant 316L housing, with an EN 10204 3.1 material certificate, that you can also use in Zone 1 / Zone 21 under CS05. Three different documents, three different jobs.

What to send us when you specify a zone

Tell us the zone (or the Group II category), the gas or dust, the pressure, the flow and the port size. We will confirm whether the housing you want is on CS05, or whether we should run the same ignition hazard assessment on a special. For coalescing duty in a hazardous area, the usual Classic Filters choices still apply: a three-port housing, a two-layer coalescing element, and a drain that actually works. The ATEX file does not change the filtration.

Call us on +44 (0)1634 724224, use the contact form, or email [email protected].