I am a registered professional engineer that has been approached by a local school district to examine suspicious welds found in several buses in the district's fleet. The welds attach the roof to the rest of the bus. The school district is concerned about the structural integrity of the buses in roll over accidents. Such accidents would be serious but also rare.

The welds in question are ugly, in part because they were made on galvanized steel components with no surface preparation. My recommendation to the district is that a CWI be brought in to look at the welds to see if they meet an appropriate AWS code. I know the ASME piping code permits some cosmetic defects in welds, so I'm not sure that the bus welds are defective just because they are ugly. An inspection by a qualified CWI seems like a reasonable first step, before any discussion of repair or modification of the buses takes place.

If am tasked with shopping for the CWI, which AWS code should that CWI have expertise in? Is there a specific vehicle welding code or would it be the structural code?