# Specifying an ATEX Radio Fleet: A Twelve-Point Checklist
Most ATEX radio purchases go wrong in the same way.
Somebody asks for a price before anybody has established what the site actually requires.
Work through these twelve points in order and you will get a specification that survives contact with an auditor.
## 1. Start with the hazardous area classification
Not the radio. The drawing.
Under DSEAR, your organisation is required to have assessed and classified the places where explosive atmospheres may occur. That produces zoning.
If you cannot lay hands on that drawing, stop here. Everything downstream depends on it.
## 2. Identify which zones people carry radios into
Not which zones exist. Which ones a person physically enters with a radio on their belt.
This single question is where most over-specification happens. Sites buy Zone 0 equipment for workers who never leave Zone 1.
## 3. Fix the category
| Zone | You need |
|---|---|
| 0 | Category 1G, Ex ia |
| 1 | Category 2G, Ex ib |
| 2 | Category 3G, Ex ic |
| 20 / 21 / 22 | 1D / 2D / 3D |
Higher categories work in lower zones. Not the other way round.
## 4. Fix the gas group
Your classification names the dangerous substances. From those comes IIA, IIB or IIC.
Remember the cost. IIC caps transmit power at 2 watts. IIA models typically run 4 watts UHF and 5 watts VHF.
Only buy IIC if hydrogen, acetylene or another IIC substance is genuinely present.
## 5. Fix the temperature class and check the ambient range
Temperature class must sit below the auto-ignition temperature of your substances. T4 covers most.
Then find **Ta** on the label and check it against your real extremes — the coldest morning and the hottest enclosed space.
Entel's DTEx range is certified to +40°C ambient. That ceiling is lower than people expect.
## 6. Add dust and mining if you need them
A site with combustible dust needs a **D** marking as well as a **G** one.
Underground mining needs Group I. M1 equipment may stay energised during a gas outbreak. M2 must be de-energised.
## 7. Decide analogue or DMR
Digital gets you better audio at the fringe of coverage, longer battery life, text messaging, and location reporting integrated with your safety alarms.
Nearly every current ATEX radio does both, and most support mixed mode so you can migrate a fleet gradually rather than in one weekend.
If you have an existing analogue fleet, mixed mode is the feature to insist on.
## 8. Size the battery to the shift, with headroom
Quoted figures are on a 5/5/90 duty cycle at maximum power. Heavy talkers and GNSS tracking reduce them.
Current benchmarks: Motorola R7Ex IIC up to 23.5 hours digital. Hytera HP715Ex 24 hours with GNSS off, 21 with it on. Entel DT982 19.5 hours digital.
Specify enough that nobody is ever tempted to change a battery inside the zone.
## 9. Specify the accessories at the same time
Not later. Not from a different supplier.
The certification covers the whole assembly. A non-approved earpiece invalidates it.
Buy the approved audio accessories, the approved battery, the approved antenna, and spare dust covers for the accessory port.
Ask for the approved accessory list in writing and file it.
## 10. Survey the coverage
A radio that meets every ATEX requirement is useless if it does not reach.
Steel structures, tank walls, reinforced concrete and dense pipework all attenuate signal badly. Two watts inside a IIC-rated area will not go as far as you expect.
Survey before you commit to fleet size. Then decide whether you need a repeater, better antenna siting, or leaky feeder for tanks and voids.
Fixing coverage after purchase always costs more than designing it in.
## 11. Check the compliance paperwork
Ask your supplier for:
- The ATEX or UKEX certificate
- The Declaration of Conformity
- The safety instructions listing approved accessories
- The IECEx certificate if you operate outside the EU and GB
On GB marking: the government has confirmed continued recognition of CE marking for equipment covered by the Equipment and Protective Systems Regulations 2016, so CE-marked ATEX equipment remains acceptable in Great Britain alongside UKCA. Northern Ireland continues to follow EU rules. This is a policy area that has moved several times, so confirm the current position before a large purchase.
## 12. Plan the ongoing control
Buying compliant equipment is the easy part. Keeping the fleet compliant is the work.
- Charged radio issued at the start of every shift, chargers outside the zone
- Spare batteries not permitted in the zone
- ATEX accessories held in separate, controlled stock
- Battery health monitored and packs replaced on a schedule
- Damaged radios withdrawn immediately, not repaired locally
- Contractors checked at the gate
- Records kept with the DSEAR documentation
## A note on what we do and do not do
Safe Signals supplies, programmes and supports ATEX-certified radio equipment, and surveys radio coverage in hazardous areas.
We are not a notified or approved body. We do not issue Ex certification, and we do not carry out hazardous area classification. Those are jobs for a competent Ex engineer and a certification body, and any supplier telling you otherwise is one to avoid.
What we can do is make sure the equipment you buy matches the classification you already have, and that it actually works across your site.
If you want a second opinion on a specification before you commit, send it over.