Rationale

In Table A1.1 the “R” classification code is K=0.15 (+/-) 0.04 for F3393 for 120ksi/530 Mpa and 144 ksi Bolt Assemblies as well as 150 ksi/1040 MPa Bolt Assemblies We think an allowed K factor as high as K=0.19 is problematic for rotational capacity testing, especially for large A490’s. It is roughly equivalent to an unlubricated plain assembly. Adding the “N” code as a supplier option, K=0.12 (+/-) 0.03, permits the producer or supplier a K range that is much less likely to have issues passing rotational capacity testing on the higher permitted end. The origins in F1136 didn’t specify K factor, just called out Grade 3, clear sealer, for the bolt, and Grade 5, lubricated sealer, for the nut. Paintability is part of the IFI 144 protocol, but in the reports referenced, the paint adhesion testing was done on the bolts, not on the nuts. If there are any paint adhesion concerns because of nut lubrication or lubricated sealers on the nuts, I don’t think they were addressed in the reports. There are no paint adhesion requirements within ASTM, RCSC, AISC, and we maintain no requirements on lubricated A325 galvanized assemblies, F1852 assemblies, F3148 assemblies, A325 and A490 prequal bolting assemblies, or thermo-diffused components. While a part of IFI 144 I don’t think it’s applicable downstream. In the IBECA reports, Dacromet averaged K=.10, Delta Protekt was K=0.08 to 0.11, Magni averaged K=0.162/0.181 depending on diameter. Two of the three were below the current “R” classification window. I think the proposed change aids in consistently passing RC tests and is within the window of research. I think the real concern is that the research proved passage of RC testing, largely done at K=0.08 to 0.11, and from that we are somehow permitting up to K=.19. We may be able to simply specify a max K for structural if RC testing is the only concern, but that is a departure from the current classification and range configuration.