[genii]

Dear All,

API RP-505 defines adequate ventilation as "Ventilation (natural or artificial) that is sufficient to prevent the accumulation of significant quantities of vapor-air or gas-air mixtures in concentrations ABOVE 25 percent of their lower flammable (explosive) limit, LFL (LEL). Reference also Section 6.3.2." (Read 6.6.2)

And 6.6.2.4.8 says "Enclosed areas can be considered as adequately ventilated if the ventilation rate provided is at least four times the ventilation rate required to dilute the anticipated fugitive emissions to BELOW 25 percent LFL, determined by detailed calculations as per Appendix B."

Also the calculation of min air introduction rate in Appendix B suggests that the calculated ventilation rate will ensure that LFL will remain 25% BELOW.

Q(fresh air rate) = G (leak rate) / C (conc of HC in air)
Q = 4.13 cfm / (0.25 * 0.05)

OR simply,

If I comply the building with 6.6.2.4.7 and 6.6.2.4.1 (of API-RP 605) then will my building have gas-air concentration below LFL, hence no risk for VCE (Vapor cloud explosion)? I have to reduce the risk of VCE hazard.

Thanks in advance.