Hazardous area equipment is rated for different zones: Zone 0 equipment for the areas of most direct risk; Zone 1 equipment where there is a consistent threat of ignition or explosion; and Zone 2 equipment where the risk is lower or intermittent.
But while it can be natural and easy to think of these hazardous areas in terms of distance at ground level from the central Zone 0, this can neglect the potential for ignition from above.
In an article published in the Institute of Physics journal IOP Conference Series: Materials Science and Engineering, authors from the Lucian Blaga University of Sibiu look at the specific example of a group of natural gas wells, a sector with high occupational risk and high explosion hazard levels.
By using 3D modelling software, they are able to identify the explosion risk for individuals working on the wells, and model the hazardous areas of highest risk in three dimensions.
These are based on combining areas with the same probability of an occurrence of a ‘dangerous element’ such as potentially explosive vapours.
“Subsequently it allows also to correctly select the electrical and mechanical equipment that will be used in that area, since electrical apparatuses that are otherwise found in normal work environments cannot generally be used in areas with explosion hazard,” they write.