ATEX

Get this the right way round and the rest of the subject follows. A place is classified into a zone by how often an explosive atmosphere is expected there. A piece of equipment is certified into a category by how well it stops itself becoming a source of ignition. A pump is never "Zone 1 rated". It is certified for use in Zone 1.

The zone definitions are in Schedule 2 to DSEAR, and the categories permitted in each zone are in Schedule 3.

The zoning is the operator's job, not the supplier's. DSEAR puts the risk assessment and the classification on the employer, and regulation 7(2) then requires that the Schedule 3 selection rules be applied to the equipment put into those places. So the classification arrives with the enquiry. Nobody should be working it out from a description of the process on a phone call.

The marking tells you the group, the category and whether the certificate covers gas, dust or both. The Regulations set out what has to be on it: Schedule 1, paragraph 5 requires the manufacturer's name and address, the UK marking, the type designation, the batch or serial number, the year of construction, and the specific marking of explosion protection followed by the symbol of the equipment-group and category. For equipment-group II it also requires the letter G for gas, vapour or mist, the letter D for dust, or both.

Two groups and five categories cover everything. Equipment-group I is for underground mines and the surface parts of them, and holds categories M1 and M2. Equipment-group II is everywhere else, and holds categories 1, 2 and 3. The categories run from most protected to least: category 1 has to keep ignition sources inactive even in the event of rare incidents, category 2 in the event of frequently occurring disturbances or equipment faults, and category 3 in normal operation.

A real example, from a pump in our range. The ATEX version of the Ebara 3S is the 3SF, marked II 2G Ex h IIC T3 to T4 Gb. That reads as equipment-group II, category 2, for gas atmospheres. Ebara deposited the technical file for the 3(L)SF and 3(L)PF with TÜV CYPRUS Ltd, notified body 2261, under Directive 2014/34/EU. The explosion-proof versions of the Grundfos SE carry II 2 GD, which is the same group and category for gas and dust, and are certified by Dekra under KEMA 04ATEX2201X, IECEx DEK 21.0017X and UKEX DEKRA 22UKEX0011X.

The temperature class is set by the medium, not by the pump. On the 3SF, Ebara publishes T4 up to a maximum fluid temperature of 80°C and T3 at 90°C, or 110°C on the high-temperature version. That is why the medium and its temperature have to be on the enquiry before anybody can say which build is certified for your area.

The requirement did not go away, and the paperwork now has two acceptable forms. Equipment placed on the Great Britain market sits under the Equipment and Protective Systems Intended for Use in Potentially Explosive Atmospheres Regulations 2016, and the wording in those Regulations is UK marking rather than CE. Certification bodies label their UKCA route for explosion protection UKEX, which is why a certificate number like DEKRA 22UKEX0011X sits alongside an ATEX one on the same pump.

CE marking has not been withdrawn here. The Department for Business and Trade announced in August 2023 that it would extend recognition of CE marking indefinitely across the product regulations it owns, and equipment for potentially explosive atmospheres is one of them. The Product Safety and Metrology etc. (Amendment) Regulations 2024 put it into the 2016 Regulations, so a manufacturer that has met the ATEX Directive's requirements and completed the conformity assessment is treated as satisfying the GB ones.

The practical effect for a specifier is that you may be offered a CE-marked ATEX certificate or a UKCA one, and for Great Britain both are current. Check the certificate covers the build you are buying, not the range it belongs to.

This is where enquiries go wrong. Certification belongs to the manufacturer and to the specific build they certified. It does not belong to the range, to the model family, or to us as the distributor.

The Ebara 3S is the clearest illustration in our range. The standard 3S is not an ATEX pump. The ATEX build is a different version, the 3SF, with its own data book and its own instruction manual. The same is true of the Grundfos SE, where the II 2 GD marking belongs to the explosion-proof versions only. Two pumps that look identical on a general arrangement drawing can be one certified unit and one ordinary one.

There is a second trap underneath it. The set only complies as a unit when the pump and the motor are both approved. An ATEX pump on an ordinary motor is not an ATEX pump set, and it is an easy thing to assemble by accident when the motor is bought separately or replaced years later. Ebara also specifies conditions of use with the certificate, an ambient range of -20°C to +40°C and atmospheric pressure of 0.8 to 1.1 bar for explosion-proof pumps, and those conditions are part of the certificate rather than advice alongside it.

Ask for the certificate against the model string on the quotation, and check the two match. We get it for the build we quote, and where the duty warrants it we take the manufacturer's engineer to site with us. Issuing that certificate is theirs to do, and so is guaranteeing what the pump then does.

Send the classification, not the process description. The zone, whether the hazard is gas or dust or both, the gas group and the temperature class the area is assessed for. Those four decide which builds are eligible before the hydraulics are even looked at.

Then the duty in the usual terms: flow, total dynamic head, the medium, its temperature and its viscosity. Say whether the motor is in the classified area as well as the pump, because the answer changes what has to be certified. And say what the medium does to materials, because a flammable solvent is usually an aggressive one too, and the corrosive duty page covers the wetted parts and the mechanical seal that go with it. Chemical duty sets the whole sequence out.

If the area is not classified yet, that is the first job, and it is not one we can do for you. Come back to us with the zoning and we will tell you which of the pumps we carry the manufacturer certifies against it, and say so plainly where none of them do.