ASME Acceptance criteria
ASME Acceptance criteria
(OP)
OK im new to this and im wondering if someone could explain to me in the most basic laymans terms the following ASME acceptance criteria.
If i was looking for what is a defect in 25mm thick pipe that is 12 inch.
ASME B31.12 Table 2 Flaw acceptance criteria
25mm ≤ t 64mm
Aspect Ratio - Surface Flaw - Subsurface Flaw
a/l a/t a/t
0.00 0.031 0.034
0.05 0.033 0.038
0.10 0.036 0.043
0.15 0.041 0.049
0.20 0.047 0.057
0.25 0.055 0.066
0.30 0.064 0.078
0.35 0.074 0.090
0.40 0.083 0.105
0.45 0.085 0.123
0.50 0.087 0.143
If i was looking for what is a defect in 25mm thick pipe that is 12 inch.
ASME B31.12 Table 2 Flaw acceptance criteria
25mm ≤ t 64mm
Aspect Ratio - Surface Flaw - Subsurface Flaw
a/l a/t a/t
0.00 0.031 0.034
0.05 0.033 0.038
0.10 0.036 0.043
0.15 0.041 0.049
0.20 0.047 0.057
0.25 0.055 0.066
0.30 0.064 0.078
0.35 0.074 0.090
0.40 0.083 0.105
0.45 0.085 0.123
0.50 0.087 0.143





RE: ASME Acceptance criteria
RE: ASME Acceptance criteria
RE: ASME Acceptance criteria
RE: ASME Acceptance criteria
RE: ASME Acceptance criteria
So, you scroll down the table to the ratio which is closest to that for the a/l aspect ratio. If your measured values exceed the a/t ratio for a surface or subsurface flaw, the flaw is rejectable.
RE: ASME Acceptance criteria
Just so i can fully get my head around this, is there any chance you can write down the equations needed so i can figure out what would be acceptable/rejectable for the dimensions of pipe i have given. (12 inch x 25mm)
Im a fractions kind of guy and maybe its the decimals that are throwing me.
Thanks
RE: ASME Acceptance criteria
So for surface flaws the formula for 'a' is t*.055
for 'l' the formula is a*4
This gives you 'a' - the height of the flaw and 'l' - the length of the flaw.
Subsurface flaws are calculated similarly.
RE: ASME Acceptance criteria
RE: ASME Acceptance criteria
My imaginary defect is 1.5mm in height and 6mm in length, so its a 0.25 ratio?
a (depth of defect) = t x 0.055 = 1.375mm
l (length of defect)= a(1.375) x 4 = 5.5mm
Thus anything over these is a rejectable defect so my 1.5mm x 6mm is rejectable, but a 1mm x 4mm would be acceptable.
If this is correct my one question is where does the (4) come from that you multiplied with (a)?
RE: ASME Acceptance criteria