1 reply to this topic

[cmp74]

Hello,

I am currently reviewing some PSV calcs for vertical vessels with external fire scenarios.AP 521 (page 36 or 37) says that bottom head area of vertical vessels can be excluded from wetted area ,if vessel is supported by skirt with vent holes.It also says in the designer has to clarify on the area of the connected piping.

Is this a common practice?

thanks in advance

[JoeWong]

Hello,

I am currently reviewing some PSV calcs for vertical vessels with external fire scenarios.AP 521 (page 36 or 37) says that bottom head area of vertical vessels can be excluded from wetted area ,if vessel is supported by skirt with vent holes.It also says in the designer has to clarify on the area of the connected piping.

Is this a common practice?

thanks in advance

Why not ? Vessel (vertical in particular) with skirt and sitting on concrete slab avoid fire reaching vessel bottom. This minimum fire relief load.

One shall take note that if there may be opening at the skirt for man entry for maintenance, then potential of reach vessel bottom may need to assess.

Piping with liquid possibly expose to fire as well. This will contributes to fire relief also.