I'm only familiar with API tanks for petroleum storage, but perhaps these Codes will provide some guidance.

Are you trying to put out a fire in the tank? For this I would look at NFPA 11.

Are you trying to protect this tank from a nearby fire? For this I would look at NFPA 15.

Suggest that you repost your general fire protection question in a Fire Protection forum

This forum, according to my understanding, deals with tank construction details, tank coatings and accessories.

Yes, we understand what you have been assigned, we understand you work for an MBA.... but ..

Is there any real fire hazard here with biogas ? .... If the tank is hit by lightning will there be a fire ? ... Is this even possible

Most storage tank fire protection systems deal with petrochemical liquid tanks undergoing a fire at the top rim...

Most of these fires are caused by lightning ...

Is your low-BTU biogas even flamable ? ..... What is the scenario where the structure of your tank is in danger of failure ?

Can anybody help here ???

MJCronin
Sr. Process Engineer

Hi , Thank you Dear @Geoff13
i want design fire protection for external of tank especially for white dome (shown in picture). white dome part is not rigid and made from flexible material .
any way thank you for ur attention to question

Well first you need to figure out where a fire can come from, how far away it is and how much radiation it emits. Also what actually is the risk if it does indeed fail? Fire? Gas cloud and explosion? Nothing serious?

Then you need to know what level of heat radiation the dome roof can with stand before it fails.

#Then you should be able to work out how much water you need to spray on the roof to stop it melting, without collapsing doe to the weight of water.

some sort of water deluge system looks like a typical application,

BTW, what's the design pressure inside that tank?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.