Emergency Venting for Motor Oil 1

[DavidMBrown]

We're designing a facility to store motor oil, a class IIIB liquid, in bulk tanks ranging from 2,000 to 10,000 gallons.

Looking at NFPA 30 para. 22.7.1.1.3, tanks with Class IIIB liquids require emergency venting if they are below 12,000 gallons.

We have calculated emergency venting air flows on the order of 98,000 to 206,000 CFH using a mean molecular weight of 289 g/mol and a mean latent heat of vaporization of 96.5 BTU/lb. The higher range of rates exceed the capacity of most normal vents. However, touring several facilities, I have never seen an emergency vent on a motor oil tank.

Does anyone have any assistance here? I don't want to specify e-vents if they aren't needed, but I don't want to omit them if they are.

Any one have any suggestions? Are my material properties in the right range?

Dave

 

[stookeyfpe]

Emergency vents are required as indicated in NFPA 30 and your calculations are correct. The reason your not seeing vents on these tanks is that it is a very common violation of NFPA 30. A lot of lubricant jobbers have very little understanding of emergency venting.

If the tanks are listed as meeting UL 142, then the tank will have an opening that allows for the installation of an off-the-shelf emergency vent.

For the indicated flow rates emergency vents are available from:

http://www.claybailey.com/shopdisplayproducts.asp?id=27&cat=U.L.+Listed+Emergency+Vents

http://www.morbros.com/AST.htm