"Fish mouth" on top of oil storage? 1

Is it similar to to the "emergency roof vent / manway cover"?

Never heard of such a thing.

3000m3 is a decent size and if you're worried about an explosion then use a frangible roof.

No pressure relief device is going to be fast enough to prevent damage if its just a small hole.

Why are you trying to design a tank and not just use an established code such as API 650?

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

Gerre,

You seem to be talking about something called a "frangible roof design" (FRD) which is mentioned in API-650 and several other references.

Yes, failure of the roof to shell joint becomes important under fire or emergency conditions. ...But there is a lot more to the story

There have been several threads on the Storage Tank forum and other places dealing with this type of design.

Some things you should know are:

- As per API-650, its not suitable for smaller diameter tanks (What is the diameter of your tank and what, specifically is being stored ?

- Robust tank anchorage design and bolt sizing is also very important

- FRD is an older method of shell protection; Insurance companies like to see properly sized emergency vents on the tank

- FRD is also discussed in Storage Tank Design Code EN 14015; Appendix K,

Research Article here:
Also see this discussion:
Give us more details about your particular tank design ... Can you post a drawing or sketch ?

Are you a new hire and is this the first storage tank that you have been assigned ?

What is the Code of Record for this tank ?... Where will the tank be located ?

I have never heard of this design called a "fish mouth"

MJCronin
Sr. Process Engineer

Suggest that you repost in the "Storage Tank Engineering" forum ....

MJCronin
Sr. Process Engineer