qman2011-
what prompts your question?
clauses 5.11 and 6.2 in d1.1 are probably the closest you'll get regarding equipment maintenance; calibration is quite another subject.
the d1.5 is a bit more wordy in clause 4.31. but that is the bridge code, not building.
you may want to inquire of the welding machine manufacturer as to their specifications for routine maintenance and calibration. "calibration" is an interesting word, especially around welding machines. there is much debate about it. is it "calibration" or "verification"? if the machine cannot be "calibrated" then is the meter that "verifies" the machine output what gets "calibrated"?
before you invest a lot of time and monies, make sure you talk to the machine manufacturer, especially about "calibration"
and if that leaves you with questions, send an email to AWS with your inquiry.
in the end, let reasonableness and common sense prevail. its hard to go wrong with those two!
ziggy
I agree with Ziggy. It's difficult to write a unifying calibration standard for welding machines. If a code requires a general statement that welding machines shall be calibrated, your best bet is to go back to the manufacturer for direction on how that can be accomplished with their machine.
A load cell is typically used to apply a load to the power supply to verify the meters are functional and within 10% of the readings obtained with calibrated meters on the load cell.
I was testing welders for a client the other day while a welding supplier was on-site calibrating the machines. I happened to walk by as he tested one machine. The ammeter stayed stuck on 200 amps, so the technician gave the meter a whack. The needle went back to zero. "Good enough" he said as he went on to the next machine.
Al
By welderbrent 
Date 08-12-2011 22:16
Edited 08-12-2011 22:19
qman,
The guys have given some good answers.
I'm willing to reach a little and guess that the bottom line is someone has a QC Manual for purposes of Audits to be Pre-Approved Fabricator status that calls for calibration of welding machines. The purpose is to document the volts, amps/wire speed, gas flow, etc to make sure welding is done within the prescribed perameters suggested by the electrode and welding machine manufacturers to satisfy some CWI who is trying to impress the customer/engineer and the fabricator with his need for volumes of data.
As stated in one of the other responses, there is generally a 10% variation allowance which still provides for the accuracy needed to be within the ranges established on one's WPS from D1.1 without having to write another WPS to cover the range being used for welding. But you will not find a lot about any of this within D1.1. Just enough to bring up some good discussions at times on this forum. LOL!! I believe if you do a search with the 'Search' button on the upper toolbar you can find other threads about this.
Have a Great Day, Brent
