On refineries, chemical plants, gas terminals and flour mills, the most frequent visitor to an explosion-hazard zone is not the process operator. It is the security officer on patrol. Here is what that means for phones, radios, torches and cameras.
The fence is not the only boundary
Most security teams know the perimeter of the site they protect down to the last gate. Fewer know where the hazardous area boundaries run inside it. Yet on any site that stores or handles flammable gases, vapours or combustible dusts, those boundaries matter more to a patrol than the fence does. Under the Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR), the employer must classify places where an explosive atmosphere may occur into zones and, where necessary, mark the entry points with the yellow and black EX sign. Zones 0, 1 and 2 cover gases and vapours, zones 20, 21 and 22 cover dusts, and the number says how likely the atmosphere is: zone 0 and 20 mean it is present continuously or for long periods, zone 1 and 21 occasionally in normal operation, zone 2 and 22 rarely and briefly.
A patrol route that passes a tank farm, a loading bay, a solvent store or a bagging line crosses those lines several times a shift. The regulations do not distinguish between an operator who works there all day and a guard who walks through for four minutes. Equipment taken into a zone must be suitable for that zone.
Why ordinary kit is the problem
An explosive atmosphere needs an ignition source, and the average security officer carries several. A mobile phone, a two-way radio, a torch, a body-worn camera, an electronic key fob: each contains a battery and switching contacts, and some have surfaces that get hot. None of that is designed to stop a spark or a hot spot from reaching the surrounding air. That is what certification is for. Standby mode does not help, because the battery and the circuits are still live, and neither does keeping the device in a pocket.
The risk is easy to underestimate because nothing happens the first hundred times. A zone 2 area is, by definition, one where the explosive atmosphere is rarely present. The one shift where a flange leaks or a filter bursts is the shift that matters, and nobody knows in advance which shift that is.
What Ex equipment actually is
Equipment certified for hazardous areas carries an Ex marking that states, among other things, which zones it may enter. Under the ATEX and IECEx schemes the equipment protection level tells you this directly: Gb (category 2G) is suitable for zone 1 and zone 2, Gc (category 3G) for zone 2 only. For dust areas the equivalent letters are Db and Dc. The marking also shows a gas group and a temperature class, which the site’s hazardous area classification will specify. In Great Britain the same principles apply under the UKCA rules, and the site’s classification will tell you which marking it accepts. A kit issued for zone 1 can go anywhere a zone 2 kit can. The reverse is not true.
Certified versions exist of practically everything a security team carries: torches, two-way radios, smartphones, tablets, cameras and even Wi-Fi access points that let the control room reach a patrol inside the zone. They cost more than consumer kit and they feel more robust in the hand, but they are ordinary tools once the crew is used to them.
Five rules for the security manager
1. Get the zone map before you write the assignment instructions. The site’s DSEAR risk assessment and hazardous area drawings show exactly where the zones are. Put those boundaries on the patrol route, not just the checkpoints.
2. Issue kit by zone, from the gatehouse. Decide which patrols enter zone 1 and which only cross zone 2, and issue certified radios, torches and cameras accordingly. Buying for the most demanding zone on the route means nobody has to work it out on the night.
3. Teach the marking, not just the rule. Officers who can read Gb and Gc, and know what the temperature class means, will spot a wrong device faster than any checklist.
4. Do not modify anything. Third-party cases, stickers over the marking, unapproved chargers and spare batteries can void the certification. Charging happens outside the zone, always.
5. Document incidents with a certified camera. A photo taken with a personal phone inside a zone is evidence of the incident and of a breach at the same time. An Ex-certified camera with optical zoom and a macro mode records a damaged seal, a leaking valve or an intruder’s route without adding an ignition source to the scene.
The gatehouse is where it is decided
Process operators go through years of training before they work in a classified area. Security officers often join a site through a contract, with an induction that covers the fence, the alarm and the visitor log. The hazardous area zones deserve a place in that induction, and the kit issued at the gatehouse is the simplest way to make the rule stick. A certified camera, radio and torch cost a fraction of one shut-down unit, and considerably less than an incident.
Armadex supplies ATEX and IECEx certified explosion-proof cameras, tablets, smartphones and Wi-Fi equipment for zone 1 and zone 2 sites, with stock in the Netherlands and the UK.
