Ventilation of inlet- oulet valve and metering- pressure reduction bld 1

[hollandhvac]

I have to review a design for an Inlet, oulet valve and metering and pressure reduction building.

This building is classified since there is natural gas going through the pipe work.

The design has been made with louvres at low level and exhaust fans in the roof. The fans need to be Ex proof to ventilate the gas from the building.

Now we have a mixture of gas, some gas is lighter than air and the others are heavier than air. I am not worried about the lighter than air because that will disappear through the fans in the roof, but the heavier than air will stay at low level or floor level. Does anybody know the requirements for this? like air speed or air changes required?

 

[SAK9]

NFPA has recomendations on ventilation rates for these types of applications.I do not think the design you have described above addresses the issue of heavier gas accumulation at low levels especially if the low level louvres are spaced wide apart.In my opinion you should provide low/high level exhaust.