wetted area of a tank 2

[Ferz]

Hi I was reading API 2000 sixth edition and in order to calculate the emergency vent, they ask for the "wetted area" what is this? I've a vertical tank and would like to know the required vent for this tank,
Thanks in advance !

 

[CH5OH]

the area of the tank enclosure, which is getting wet (in contact with liquid)

 

[sshep]

Ferz,
Wetted area is a relief type term used in fire size venting calculations. Although I cannot access my API2000 due to a technical problem, I am pretty sure that wetted area will be the entire surface area of the tank wall for a normal tank which can be operated full of liquid- although it could be somewhat less it there is an overflow or something that prevents filling the tank all the way. The calculation of the emergency vent rate in case of fire will apply a heat flux to a surface area of stored liquid which is exposed to fire, and use heat of vaporization to convert the heat load to a fire venting rate. Wetted area for a normal tank will not usually include the floor (if set on the ground) or the roof (an API 650 or 620 tank has a level-so there is no liquid in contact with the roof).
best wishes,
sshep

 

[Ferz]

Great thanks to sshep and chO5h for your help!! it was really helpful!