When is foam system needed

[IFRs]

Under what circumstances do you need a foam system for a steel cylindrical above-ground storage tank equipped with an internal floating roof storing volatile organic liquid? What organization and what specific code requires a foam system? I know that NFPA-11 describes a foam system and NFPA-30 mentions foam systems, but who or what says you have to have one? Is it OK to NOT have foam protection for such a tank?

Thanks !!

 

[DavidCR]

Following NFPA 30,
-Classify the contents, how risky is the location?, is the tank build following a standar?.
-2-3.2.1 Will tell you what kind of tank you have.
-Consider table 2.1. and this may indicate you a foam system requirement.
-2-9.1 May apply.
Internal floating tanks fires are more difficult to combat than open floating roofs if a foam system is not provided, since there is no acces to throw water or foam to the rim area.
Hope this helps.