pmover
Mechanical
- Sep 7, 2001
- 1,507
Fellow engr's,
I'm headed to a seminar now and not able to look into the matter now. But . . .
A power plant is replacing existing flanged steam butterfly valves with flanged gate valves of a length greater than the butterfly valves. the system pressure/temp is 600 psig/800°F respectively. (As such, a portion of existing piping will need be cut and removed. Thus, there will be a new flange and perhaps a pup (short length of replacement pipe) welded to new flange prior to final installation. The final weld testing/examination is the unknown. Assuming the pup is from a section of pipe that has already been hydrotested, what are and where can i locate the criteria for testing/examining the final weld? Should the pipe NOT be pre-tested and the pipe installed, then the final weld and section of piping does need to be hydrotested; thus ASME B31.1, Section 137 (Pressure Tests)applies.
Also, are there minimum lengths between welds on power plant piping (i.e. min length of pipe must be xyz-feet)?
Thanks!
-pmover
I'm headed to a seminar now and not able to look into the matter now. But . . .
A power plant is replacing existing flanged steam butterfly valves with flanged gate valves of a length greater than the butterfly valves. the system pressure/temp is 600 psig/800°F respectively. (As such, a portion of existing piping will need be cut and removed. Thus, there will be a new flange and perhaps a pup (short length of replacement pipe) welded to new flange prior to final installation. The final weld testing/examination is the unknown. Assuming the pup is from a section of pipe that has already been hydrotested, what are and where can i locate the criteria for testing/examining the final weld? Should the pipe NOT be pre-tested and the pipe installed, then the final weld and section of piping does need to be hydrotested; thus ASME B31.1, Section 137 (Pressure Tests)applies.
Also, are there minimum lengths between welds on power plant piping (i.e. min length of pipe must be xyz-feet)?
Thanks!
-pmover