Pneumatic Tests: Stored Energy & Safe Distances
Pneumatic Tests: Stored Energy & Safe Distances
(OP)
Hi,
I have a very low pressure vessel which has been designed to BS PD5500. It operates in the vertical orientation in the range -100 to +200mbar internal pressure, and is approximately 6m ID by 15m high with conical ends. It is really more of a process vessel, and operates between 400-550 degrees centigrade.
PD5500 doesn't seem much use in defining safe test pressures for pneumatic test, and doesn't seem to have anything on calculating stored energy. Indeed, when I've looked into methods of calculating stored pressure energy in pnuematic tests, it appears to be a trickier task than I'd first expected. ASME PCC-2, Article 5.1, Mandatory Appendix II and III, is maybe one potential method I read about, but I can't find a copy of the text.
I have read 1.1x design pressure from BS EN 14015 (Storage Vessels), this being for testing roof structures, i.e. what to compress the roof void to in a liquid filled vessel. But I am hesitant to base anything on this. And this mentions nothing of relating the energy value to a safe clearance at test. :/
I am reluctant to recommend anything above the 10% design pressure as a leak test only (as per PD5500), because of the inherent dangers of pneumatics, and a lack of any concrete recommendation from some code. But there is a conflict created there, because the vessel will then effectively be 'tested' on first operation, at a value never exceeding 1.0x design pressure (which I don't think is acceptable).
So any advice on any of the following, would be greatly appreciated:
1. Recommendations for pneumatic test pressure for this kind of vessel.
2. Approaches to estimating the stored energy in a vessel at an arbitrary test pressure.
3. Approaches to relating stored energy values to a safe test clearances.
Thanks.
I have a very low pressure vessel which has been designed to BS PD5500. It operates in the vertical orientation in the range -100 to +200mbar internal pressure, and is approximately 6m ID by 15m high with conical ends. It is really more of a process vessel, and operates between 400-550 degrees centigrade.
PD5500 doesn't seem much use in defining safe test pressures for pneumatic test, and doesn't seem to have anything on calculating stored energy. Indeed, when I've looked into methods of calculating stored pressure energy in pnuematic tests, it appears to be a trickier task than I'd first expected. ASME PCC-2, Article 5.1, Mandatory Appendix II and III, is maybe one potential method I read about, but I can't find a copy of the text.
I have read 1.1x design pressure from BS EN 14015 (Storage Vessels), this being for testing roof structures, i.e. what to compress the roof void to in a liquid filled vessel. But I am hesitant to base anything on this. And this mentions nothing of relating the energy value to a safe clearance at test. :/
I am reluctant to recommend anything above the 10% design pressure as a leak test only (as per PD5500), because of the inherent dangers of pneumatics, and a lack of any concrete recommendation from some code. But there is a conflict created there, because the vessel will then effectively be 'tested' on first operation, at a value never exceeding 1.0x design pressure (which I don't think is acceptable).
So any advice on any of the following, would be greatly appreciated:
1. Recommendations for pneumatic test pressure for this kind of vessel.
2. Approaches to estimating the stored energy in a vessel at an arbitrary test pressure.
3. Approaches to relating stored energy values to a safe test clearances.
Thanks.





RE: Pneumatic Tests: Stored Energy & Safe Distances
http:/
Steve Jones
Materials & Corrosion Engineer
http://www.linkedin.com/pub/8/83b/b04
RE: Pneumatic Tests: Stored Energy & Safe Distances
Regards,
SNORGY.
RE: Pneumatic Tests: Stored Energy & Safe Distances
In any event, this previous thread may be of interest:
thread378-293859: Vessel Stored Energy Limits
There is a simple, crude spreadsheet that you can still access at the end of the link.
Regards,
SNORGY.
RE: Pneumatic Tests: Stored Energy & Safe Distances
I would use the references that SNORGY offered (very similar to my experince)
Calculate the TNT value and then go to something like OSHA or other government Codes for requirements on safe distances.
ASME VIII div 1 has some guidlines for pneumatic tests and the 1.1 x design pressure is specified there too.
ASME VIII Div 2 is similar to PD5500 and also has provisions for pneumatic testing.