The only thing that I know for sure about it is, that if you are using wire you must use a CV machine.

The only structural "code" that I know of have been the new guidlines put out by FEMA and they are FEMA-350, 351, 352 and 353.

The current requirements for CA are delineated in the 1997 Califonia Building Code. The FEMA documents have only recently been released. The City/County of Los angeles and other local jurisdictions have elected not to adopt these recomendations. The specific requirements for seismic zones 3 and 4 may be found in the AISC Siesmic Provisions (1997/1999). The specific requirements for structural welding vary between jurisdictions and what part or parts of the codes they have adopted.

The FEMA recomendations are not consensus documents and are not quite complete as some of the fabricator programs, NDT personnel qualifications, duties for the special inspectors, etc. are somewhat biased. The design criteria (FEMA 350) has not been adopted by the engineering communities as well. These documents may be obtained through FEMA's 800 number at no charge, I think as a Level III you may be surprised at some of the information within the docs, particularly FEMA 353.

I have requested information from the ASNT technical services manager and he was a bit surprised at their (FEMA) specifications as well. I encourage you to contact FEMA and review the docs for yourself. I have been reviewing FEMA 353 for the SEAOSC SAHC and have a number of pages of commentary and recomendations.

The AWS currently has their own draft doc (AWS D1.8-XX) which may be obtained as well and applies specifically to SFRS (i.e. SMRF connections) dated September of this year.