Specialist services
Hazardous area classification
A practical assessment of your process, with clear zone drawings and the reasoning behind them.
- Typical engagement
- 1 to 4 weeks
- Where it applies
- Any site handling flammable gas, vapour or dust
- You receive
- Zone drawings and a classification report
- Working to
- BS EN 60079-10-1 · 60079-10-2
Knowing where the risk is, and why
Classification is an argument, not a colouring exercise. It starts with the places a flammable substance can actually leave the process: a seal, a vent, a sample point, a hatch that is opened once a shift. Each one is graded by how often it releases and how much, and that grading is what sets the zone.
Ventilation then decides how far the zone reaches. A well-ventilated outdoor pump skid and the same pump inside a closed building are not the same problem, and the extents should show that. We work the numbers rather than defaulting to a radius somebody used on the last plant.
Gas and dust are assessed separately. Gas follows 60079-10-1 and turns on release rate and dilution; dust follows 60079-10-2 and turns on layers, housekeeping and the chance of a cloud forming. A site with both gets both, drawn so nobody has to guess which convention a zone belongs to.
What the study covers
- Release source inventory
- Grade and rate of release
- Ventilation assessment
- Zone type and extent
- Equipment category selection
- Drawing and register update
How the work runs
From process data to defensible zones.
Gather
Process flow diagrams, substance data, ventilation rates, layouts and whatever classification you already hold.
Assess releases
Walk the plant, list every release source, and grade each one by how often and how much it releases.
Draw the zones
Extents calculated from release rate and dilution, then drawn in plan and elevation on your own layouts.
Review with you
A working session with your process and engineering people before anything is issued as final.
Your questions, answered.
A common interval is three to five years, but the interval matters less than the triggers. A new substance, a change in throughput, a modified vent, a new building around an outdoor plant, or a modification to the ventilation all change the answer and should bring the review forward. We set both when we issue the report: an interval, and the specific list of changes on your site that should override it.
Yes. Dust is assessed to BS EN 60079-10-2, which is a different argument from gas: it turns on layer thickness, housekeeping and whether a cloud can form, rather than on release rate and dilution. Where a site has both, the drawings show both and label which convention each zone belongs to, because mixing the two on one drawing is how equipment gets specified for the wrong hazard.
Usually, yes, and it is normally the cheaper route. If the existing study has a readable basis of classification we review it against the plant as it is today, mark up what has changed and reissue. If there is no written reasoning behind the zones — just shapes on a drawing — we will tell you, because an extent nobody can justify is not something we can put our name to.