UA-69298255-1 ASME B31.3 Quality Factors

ASME B31.3 Quality Factors

July 10, 2017

Quality factors are used in pressure design and, in addition for castings, design for occasional loads and displacement stress range. They are applied at longitudinal and spiral weld joints, and for castings.

The quality factors for weld joints are provided in Table A-1B of the Code, and vary from 0.6 to 1.0. The basis for these factors is summarized in Figure 3.2. The quality factor for furnace butt weld pipe is the lowest, at 0.60. Note that this quality factor does not generally effect the thickness of furnace butt weld pipe, since it is only permitted for Category D Fluid Service, and furnace butt welded pipe comes in standard wall, with a maximum diameter of DN 100 (NPS 4).

Electric resistance welded pipe has a quality factor of 0.85. This cannot be improved with additional examination.

The quality factor for electric fusion welded pipe varies from 0.80 to 1.0, depending upon whether it is a single or double sided weld, and the degree of radiographic examination (none, spot, or 100%). The quality factor for API 5L spiral weld pipe is 0.95; the welds are 100% UT examined per the specification.

The quality factors for castings are described in para. 302.2.3 of the Code. Due to the conservative stress basis, the casting quality factor for gray and malleable iron is 1.0. The casting quality factor for other castings is 0.8, unless supplemental requirements are met. These supplemental requirements involve additional examination and/or machining of surfaces to enhance examination. Compliance with these supplemental requirements can increase the quality factor to 0.85 to 1.0, depending upon which supplemental examinations are performed. #Little_PEng

Please reload

Rate UsDon’t love itNot greatGoodGreatLove itRate Us

LITTLE P.ENG. FOR ENGINEERS TRAINING

3705 Fonda Way #18 Southeast Calgary, T2A 6G9

Canada

Bay area, California

Stay Connected

  • Yelp Social Icon
  • Facebook Social Icon
  • Twitter Social Icon
  • LinkedIn Social Icon
  • yp-logo-original
  • Yelp Social Icon
  • Google Places Social Icon
  • Pinterest Social Icon