"Modificatopn" of Hazardous Zones

[pristava]

European Standards provide "Concept of Walls" to modify Hazardous Areas. For the light gases, a wall located close to the potential gas leak makes hazardous area on the top of the wall,plus little beyond but generally another side of the wall is unclassified area.
/Book - A.Mc.Millan "Electrical Installations in Hazardous Areas"/
I am checking American Standards - API, NPFA but I didn't find this concept here.
Is this "Concept of Walls" is covered by International ISO Standards.
Our problem - Hazardous Area Zone2 (light gas leak) goes 3-4 ft beyond a fence where is private property.

 

[jcaiken]

I would suggest that you check the standard used to specify the hazardous area as many have recently been revised (e.g. IP-15 in 2002). A review based on the latest standard and accurately locating the specific release source may relocate the hazardous area boundary within your fence.

For example, a natural gas leak from a piping flange etc. would typically be only 1.5m radius under IP-15(2002).

See if some remedial work is possible to reduce the size and location of the hazardous area, e.g. restricting the size of the release or relocating the release point.