A fabricator has submitted an I12x11.51 as a substitution for an I12x11.7. I can't find properties for an I12x11.51. Can anyone tell me if an I12x11.51 is a standard aluminum shape in North America?
Get the spec. of the material (alloy & temper) & origin of supply. After some years in the aluminium industry I know this to be a bit of a "black art" & stuff can come from all over the world. Quality control in US/UK/EU should require some certification of origin. If not, best to leave.
Miecz, whether or not this is standard is not really the point here.
The point is that this is a request for a change, a change order request, and, in this circumstance, it is the responsibility of the fabricator to show to you that the substitution is at least as good as your original callout. He has the burden of proof. He needs to show you the paper work. You do not need to do any investigative work here. This should be your normal "modus operande" here. (method of operation)