NCPWB Bulletin - Risk of Brittle Fracture of Carbon Steel Piping During Hydrostatic Testing
NCPWB Bulletin - Risk of Brittle Fracture of Carbon Steel Piping During Hydrostatic Testing
(OP)
Have any of you read this bulletin from NCPWB (see link below)? Any opinions on this?
Link
I checked a handful of ASTM A53B & A106B mill test reports and about half did not comply with the manganese to carbon ratio of 5+. Also, I didn't see "grain size" anywhere on the MTR's.
Also curious if anybody knows how they calculated the hydrostatic test pressures on page #3.
14" standard weight, per ASME B31.9.
P = 2SE(T-A)/D
P = 2*14600psi*(0.375"-0)/14"
P = 782psi
0.2 * 782psi = 156psi. the chart in the bulletin shows 163psi.
Thanks
Link
I checked a handful of ASTM A53B & A106B mill test reports and about half did not comply with the manganese to carbon ratio of 5+. Also, I didn't see "grain size" anywhere on the MTR's.
Also curious if anybody knows how they calculated the hydrostatic test pressures on page #3.
14" standard weight, per ASME B31.9.
P = 2SE(T-A)/D
P = 2*14600psi*(0.375"-0)/14"
P = 782psi
0.2 * 782psi = 156psi. the chart in the bulletin shows 163psi.
Thanks





RE: NCPWB Bulletin - Risk of Brittle Fracture of Carbon Steel Piping During Hydrostatic Testing
Will it really matter in most cases?
RE: NCPWB Bulletin - Risk of Brittle Fracture of Carbon Steel Piping During Hydrostatic Testing
RE: NCPWB Bulletin - Risk of Brittle Fracture of Carbon Steel Piping During Hydrostatic Testing
RE: NCPWB Bulletin - Risk of Brittle Fracture of Carbon Steel Piping During Hydrostatic Testing
My assumption is that mill test at usually much higher pressure is no problem as it should be at room temperature therefore it follows that in construction failures the ambient temperatures must be low. I looked at Chuck Becht link which he quotes temperatures under 60F for both test and operating and wonder if anyone can elaborate on the 60F/15 DegC which I guess maybe comes from ASME BPVC over and above min and also why both test and operating as these will be different pressures. Our standards actually stipulate min 17 DegC for hydrotest but we are in Middle East and have no problems maintaining.
I will be raising this to be addressed our contractors especially in regard to possible changes to curves in B31.3 but would welcome any further background information.
RE: NCPWB Bulletin - Risk of Brittle Fracture of Carbon Steel Piping During Hydrostatic Testing
RE: NCPWB Bulletin - Risk of Brittle Fracture of Carbon Steel Piping During Hydrostatic Testing
With the potentially greater stress induced under a B31.3 hydro test than under a B31.1 test, more concern should be given with regard to test temperature. It is noted that typical Mn:C ratios for the past 50 years for A-53 and A-106 have been between about 3:1 to 5:1.