Vessel Freezing
Vessel Freezing
(OP)
I have a 30 year old pressure vessel constructed from BS-150-151-28A plate. The vessel is in good condition and is still at nominal wall thickness of 19.0mm.
During an operational upset the vessel was subjected to a temperature of -14 degrees C, it was only at this temperature for 10 minutes and was below freezing for a maximum of 1 hour 30 mins.
It did not fail during this stage and subsequent visual inspection shows no anomalies - NDT of welds being planned.
Would the low temperatures and timescale cause problems in this instance.
Thanks
Jim
During an operational upset the vessel was subjected to a temperature of -14 degrees C, it was only at this temperature for 10 minutes and was below freezing for a maximum of 1 hour 30 mins.
It did not fail during this stage and subsequent visual inspection shows no anomalies - NDT of welds being planned.
Would the low temperatures and timescale cause problems in this instance.
Thanks
Jim





RE: Vessel Freezing
Was the vessel under pressure during this operational event, and what actually caused the decrease in temperature? Your visual inspection and nondestructive testing statements are acceptable to evaluate structural integrity. As far as low temperature effects on material properties, I would say if the visual inspection and NDT results are acceptable, the vessel should be acceptable for continued service. This assumes that the vessel was manufactured from carbon or low alloy steel plate.
RE: Vessel Freezing
RE: Vessel Freezing
RE: Vessel Freezing
This particular grade of steel is a low carbon steel.
Like JStephen I was under the impression that once returned to normal conditions the grain structure would be unaffected and that the risk was at the time of low temperatures, I am having the NDT done as confirmation that no internal cracking has resulted.
RE: Vessel Freezing
RE: Vessel Freezing
RE: Vessel Freezing
Semi cluey operational folks will try to grandfather a vessel for these new low temperatures, but resist this at ALL COSTS!