Convert filter vessel to piping component to avoid PSVs to flare

[sunnyfriday]

Hello experts,

What criteria (volume/pipeline dia/?) should be utilized to make the filters/strainers vessels as a Piping component. The intent here is to avoid safety valve for fire case or blocked in case by avoiding pressure vessel. Following are more details regarding proposed strainer.
Material: Gas Oil @ 670F temp.
Proposed basket strainer (2 feet ID x 5 feet height) location is on grade (discharge of pump) so fire case psv will be required for liquid vaporization due to pool fire as per ASME VIII. We do not have underground closed hydrocarbon drain so only option is to raise PSV by 40~50' upto piperack so it can slopped down to flare header.

Is there any other option to avoid PSV? credibility of administrative controls to avoid fire case psv?

Thanks for your time.

 

[don1980]

The exemptions from ASME Sec VIII scope are listed in section U-1 of that code.

The vessel you describe isn't exempted if it's built to ASME Sec VIII. To avoid sec VIII pressure relief compliance requirements you have to have build the strainer to pipe code (ASME B-31.3) rather than pressure vessel code (ASME Sec VIII). In such cases the strainer is regarded as a piping component rather than a pressure vessel.

Piping components must be protected from overpressure, but you have a much wider range of options as compared to ASME Sec VIII. For example, you can use operating procedures, etc, rather than safety valves.

 

[RaRo]

Fire case is left to user's discretion.
You could consider the 'potential energy' of your equipment exposed to fire.
An usual recommandation is that if the design pressure times the volume is less than 250bar.litres, no fire relief is required as long as vessel burst will not do critical damage such as domino effect, spreading the fire (liquid leak, missile fragment causing leaks of lammable material), damage to critical EHS safeties, irreversible damage to person.
This criteria was designed to avoid clutterring every little piece of accessory that is isolable from the main equipments/inventories with relief devices.
This is an approach cautioned by the API... I do not know for ASME.

Otherwise a probability-consequence risk based reflexion could be used too.

 

[TD2K]

Fire case of course refers to the vessel being blocked in when there is a fire in a area.

I've seen companies have procedures in place to drain vessels of liquid when not in service so there is nothing to vaporize so no relief condition.

Alternatively, can you leave a block valve on the off-line filter open so you have a relief path for any generated vapors?

Other clients will insist if it's a pressure vessel, it must have a PSV (and some regulatory agencies can take this approach).

The place I'm currently working at has entire columns (18" dia, 20' high) constructed of piping components.