GR 448 Cat II -45C vs. GR 448 Cat III -45C vs

The difference is precisely as you have stated: Cat III notch toughness qualification means qualification on the basis of absorbed energy only, without measuring the percent are failed in shear on the fracture surface. If the governing Code Of Construction is CSA Z662, you can make the substitution of Category III for Category II for a limited run length of pipe of 100 metres.

Unless you are in CO2 service, in which case you can never make the substitution; or unless your hoop stress exceeds the upper bound for Pipe Threshold Stress Value (PTSV) for the corresponding pipe size as tabulated in the right hand column in Table 5.3, in which case again the substitution is not permitted.

The intent of the Code is to limit the potential length of crack propagation to a few joints of pipe.

"percent are" should read "percent area".

Stupid iPad auto-correct.

And, "Table 5.3" should be "Table 5.2".

I will blame the stupid iPad for that one, too.

Thanks Snorgy-I appretiate your input.

Yes, the iPad continues to dominate, control and auto correct!!! If only it could decipher standards!!

thanks
specs

Sorry, liquids LVP crude line, no CO2 and length is great than 100m