Trim Class

[honche725]

hi everyone! i'd like to know what TRIM CLASS for a vessel/equipment is. as i understand it is the material spec of the pipes connected to it. is this correct?

but what if the inlet and outlet piping materials differ? what would then be the trim class of that vessel/equipment? do you only consider major flow lines into and out of it?

thanks a lot.

 

[TD2K]

The trim class is essentially the material spec that you want any trim on the vessel designed to.

The way I've seen it, let's say you have a carbon steel vessel with carbon steel piping in and out of it that is called "A" spec. The trim can be given a line number with A spec for material. This could apply to a valve and a blind, blind, etc. Anything attached to the vessel that is part of the pressure envelope and that is not provided by the manufacturer. Insulation, heat tracing, etc can all be part of the 'trim' number. My experience is that it's usually in the format of a line number.

It doesn't have to be a single spec. I'm working on a job with a vacuum tower where the top section of the column is carbon steel (A spec in the above case) while the lower section is all 5 chrome piping. It's best to understand what the 'trim' is going to be used for to ensure that what you put down for the trim class is appropriate (while the piping we are attaching to the lower section of the vacuum column is 5 chrome, the tower itself is clad with stainless steel).