ATEX instrument installation process map

What is in this map

16 steps across 5 swimlanes and 6 phases, with 2 decision points.

Swimlanes (who does the work)

Field Service, Engineering, ATEX Safety, QA and Commissioning

Phases (left to right)

Classification & Requirements, Certification Verification, Technical Review, Installation, Inspection & Documentation and Commissioning & Handover

Why map this process

Getting the hazardous-area zone right at row 2 is the premise everything downstream depends on, which the map states outright in its own note: every certification check that follows is meaningless if the zone here is wrong. Reading it off the customer's area classification drawing and confirming it on site, rather than assuming it from the process description alone, is what stops a Zone 1 assumption being applied to what is actually Zone 21 dust-hazard territory.

The equipment-rejection branch at row 6 is drawn with no alternative path back into installation for a non-conforming unit — a mismatched marking is a hard stop, sent back to procurement, regardless of schedule pressure. That is a deliberate design choice: an ATEX marking that does not match the zone, gas group and temperature class is not a risk to be managed on site, it is a certification that does not apply here.

Every step in the map

This is the spreadsheet behind the diagram. The numbers in “Goes to” are row numbers, which is exactly what the editor’s “Line to” column holds — so you can read the flow here and retype any part of it.

The decision points

Every branch in the map, with the label on each outgoing line. These are the questions the process has to be able to answer.

• 5. ATEX marking matches **zone, gas group and temperature class**?

  Owned by ATEX Safety · Certification Verification

  • Yes → step 7
  • No → step 6

• 11. Installation passes **ATEX inspection**?

  Owned by ATEX Safety · Inspection & Documentation

  • Pass → step 13
  • Fail → step 12

Notes on specific steps

These notes travel with the map. In the editor they live in the Notes column and appear when you open a box.

2. Determine hazardous-area classification (*zone*)

Zone 0/1/2 for a gas atmosphere, Zone 20/21/22 for combustible dust, read off the customer's area classification drawing and confirmed on site. Every certification check downstream is meaningless if the zone here is wrong.

4. Verify ATEX equipment certification against *zone, gas group and temperature class*

Marking checked field by field against the zone: protection type, gas group (IIA/IIB/IIC) or dust group, temperature class (T1-T6) and IP rating, not just an "ATEX" stamp on the nameplate.

6. **Reject** non-conforming equipment, request a correctly certified unit

No exceptions for schedule pressure: a mismatched marking is a hard stop, not a risk-accepted proceed. The unit goes back to procurement, not into the ground.

8. Define installation requirements: cable glands, earthing and cable routing for the zone

Ex-rated cable glands sized to the cable outer diameter, a dedicated earthing/bonding conductor sized for the zone, and a barrier or galvanic isolation fitted on every intrinsically safe loop.

13. Complete ATEX installation documentation

Certification record, inspection report, earthing/bonding test results and the as-installed cable schedule filed together, the set an auditor or the customer's own safety authority will ask for.

Making it yours

Marking verification (row 4) is checked field by field — protection type, gas group, dust group, temperature class and IP rating — against the specific zone from row 2, not as a single 'has an ATEX stamp' checkbox. When you adapt this map for your own hazardous-area work, keep that granularity: a certificate valid for one gas group or temperature class can still be the wrong certificate for the zone the instrument is actually going into.

What to watch out for

• Do not let installation-requirements planning (row 8) get treated as generic wiring practice. Ex-rated cable glands sized to the cable's actual outer diameter, a dedicated earthing/bonding conductor sized for the zone, and a barrier or galvanic isolation on every intrinsically safe loop are named explicitly here because a hazardous-area installation fails on these details, not on whether the instrument itself is correctly certified.
• The post-inspection rework loop (row 12) returns to the installation step, not to a documentation fix. A failed ATEX inspection means the physical installation itself needs correcting before re-inspection, and this map is explicit that the loop goes back to installing, not to writing around the finding.
• Do not compile the ATEX documentation file as an afterthought once commissioning is already scheduled. Row 13 places it before commissioning specifically because the certification record, inspection report, earthing/bonding test results and as-installed cable schedule are the set an auditor or the customer's own safety authority will ask for — assembling it after the fact means reconstructing evidence rather than recording it.

Frequently asked questions