Special Inspections for 5/16" or less fillet welds 4

[KirkGH]

The 2009 IBC states 1704.3 Exception 2.1 that Single pass fillet welds not exceeding 5/16" in size do not require continuous inspection. Since IBC defers to AISC 360-10 Chapter N I can't find an exception to continuous special inspections for small fillet welds in Chapter N.

Can somebody help me find this? It must be in the Code somewhere. A reference that explains the Chapter N provisions would be helpful. Know of one?

KGH

 

[MrHershey]

First off, 2009 IBC would refer to AISC 360-05, not -10. Very important distinction because chapter N was added in AISC 360-10. There's a quick QA blurb in AISC 360-05 Chapter M and again in the Code of Standard of Practice, but not much on special inspection beyond whatever the DOR requires (which would typically be whatever the IBC requires). In IBC 2012 and IBC 2015, all special inspection requirements for structural steel have been removed and replaced with a reference to AISC 360 (understood to be AISC 360-10).

Now, on to Chapter N. The reason you can't find an exception for continuous inspection is because NO welds require continuous inspection while they're doing the weld. Every single task in Table N 5.4-1 "Inspection Tasks During Welding" is type O, for observation on a random basis. So while IBC 2009 doesn't require continuous inspection on only 5/16" or smaller fillets, AISC 360-10 doesn't require continuous inspection on any welds. This is a point of contention between AISC 360 committee and some structural engineers groups (like SEAOC, PDF link) as it actually represents a decrease in the amount of inspection required for multipass fillet welds and partial groove welds (CJP are still subject to NDT which should in theory catch any of the problems inspection is trying to prevent anyways). If individual engineers are concerned with this decrease in inspection they would need to include specific requirements for inspection above and beyond what AISC 360-10 requires in the construction documents.

 

[KirkGH]

Thanks.

KGH