ASME B31.1 Table 136.4

[chungming]

based on ASME B31.1 Table 136.4 which any joint its temperature is over 400 centigrade degree shall be under radiographic examination for pipe size above 2".For pipe size below 2", is it a good engineering practice to provide 100% RT regardless of pipe size.

for the moment I only provide a visual examination-VT 100% for pipe NPS 2 and less. Is it Sufficient?

 

[bam8888]

The question of whether it is sufficient depends on many factors. The more critical the service of the pipe (how dangerous if failure occurs) certainly plays a role. A history of in service failures (if available) at the weld seam would also indicate need for higher levels of NDE during new construction.

You may also consider the possibility that radiography of such a small pipe may be difficult or impractical. Since the Code does not mandate RT of 2" and smaller pipes, you should check with the end user of the equipment to see if they have more stringent requirements. If so, other NDE techniques, such as ultrasonic (UT), magnetic particle (MT), or penetrant testing (PT) will provide better indicators of weld seam defects than visual examination alone.

Hope this helps

 

[Mr168]

RT on 2" pipe isn't difficult.

However, I can't think of many instances in a B31.1 application where you would have many lines over 750°F or sufficiently high in pressure where 2" pipe would be put into service and butt welded. Most everything I've seen at that size is socket welded for B31.1 applications. I'd imagine the folks at ASME are also along those lines of thinking, though I've been wrong a time or two before...