10.027 NDT of Fillet Welds?

Q What NDT inspection criteria is required by code for fillet welds?

— Structural Engineer from Houston, TX.

A 1/07 – Response prepared by Tim Hart, S.E., an Associate at Dasse Design Inc.; Doug Williams, P.E., a consulting and welding engineer; and Dave Palfini, Divison Manager for Testing Engineers and an ASNT Level III

There are no general requirements for NDT of fillet welds in the 2001 CBC, AWS D1.1, AWS D1.8, or the AISC Specifications. The requirements in CBC Section 1703 apply only to the welds noted, and are the minimum NDT requirements. The Engineer has the option of requiring testing beyond the minimum requirements, including NDT of fillet welds, as part of the Statement of Special Inspections prepared by the responsible design professional. However, such testing is not specifically required by code.

Appendix Q of the 2005 AISC Seismic Provisions for Structural Steel Buildings (AISC 341) now lists specific locations where NDT is required for connections resisting seismic forces. The only connections that could potentially involve fillet welds are welds within the “k-area” of the section and repairs within the plastic hinge region of reduced beam section (RBS) moment frame connections. These provisions have not yet been adopted into the California Building Code.

FEMA-353 recommends the Engineer to develop a Quality Assurance Plan and indicate the appropriate Seismic Weld Demand Category and Seismic Weld Consequence Category for each welded joint on the design drawings. Magnetic particle testing is specified for fillet and PJP welds in all but two categories.

If desired, Magnetic Particle Testing (MT) should be used to test fillet welds. Ultrasonic Testing (UT) should not be specified for fillet welds.