Storage Tank Inerting Required?

[Robert321]

I am working on a low presssure storage tank that will contain mostly water with some organic. Process simulation shows the vapor pressure of the organics is never quite enough to reach the lower explosive limit.

I think the tank should be inerted just in case, but I need to know if there are any codes or regulations to back my position? I have searched NFPA & API, but found no mention of this subject, so far.

Thanks,
R

 

[25362]

Visit thread798-76953 and thread378-91957.

 

[Robert321]

Thanks for the links. Those are very good discussions, but they don't quite address my problem.

While I understand the technical aspects of an explosive atmosphere, I am not so welll acquainted with the applicable codes and regulations, especially as concerns inerting.

I was hoping someone familiar with the codes could point me at sections that address use of an inert atmosphere.

Thanks,
R

 

[johngerhart]

I am surprised NFPA 30 does have some information . In any event , if there is no ignition source suchas an agitator , inerting should not be necessary . I am assuming the liquid is dip piped into the tank . Other possible sources for information are Factory Mutual Loss Prevention Manuals and the Center For Process Safety

 

[TrevorP]

What did you use to estimate the vapour pressure above the water? I remember reading an article some time ago that showed that, according to Henry's law, even at very low concentrations in the water phase, they can still be above the LEL in the vapour phase. I'll see if I can find a reference.