Joint efficiency & Radiography - API 650

[kvbalu]

What is the relationship between Joint efficiency and Radiography per API 650 ? Can a Joint efficiency of 1.00 be used for design and Spot radiography be applied during construction. What is the normal engineering practice ?

 

[JoeTank]

The basic design requirements of API-650 are to use a joint efficiency of 1.0 and the RT requirements of Section 6. The extent of RT is based upon the plate thickness. At the low end of the scale (thickness of 3/8 and less) only a limited number of RT shots are required. At the high end (thickness greater than 1 inch) full RT is required.

There are two additional options available when specified by purchaser. Appendix A uses less RT than the basic Standard with E = 0.85. When no RT is performed E = 0.70.

The term "joint efficiency" is probably not the best term to use. Perhaps "quality factor" would be better, but that's another topic.

Steve Braune
Tank Industry Consultants

http://www.tankindustry.com