Hey Ted,
It would be difficult to try to interpret the customers' understanding of "best commercial practice" if they don't define what they seek. Every application has a "best" or "cost-effective" method to reach an end product/use. Your post is a bit vague on the particular application as to size, material, number of items if a multiple piece job, and a "method of production" to complete in a timely manner. Also, what are the certs & codes required by the customer? It would be up to them to provide the necessary parameters to you. Do they have an engineering dept.? Are they familiar with welding codes? Sounds like they expect you to do all the homework. If they are, who pays for the research & design? You or them? What liabilities are involved? If you provide more info, I'm sure there are those here who will provide the always superb responses to your query.     Denny

To be fair to the bidding contractors they (the owner or the designer) should provide contract specification documents so all bidders can bid on the same requirements. Is it a pipe or structural job? If a pipe job what service is it providing? You can probably figure out what code by answering the last question. If structural it most likely will be AWS D1.1. If pipe it could be ASME 31.1 power piping, 31.3 process piping, 31.5 refrigeration piping, 31.9 building service piping. API Standard 1104 deals with the welding of pipelines and related facilities. Many codes state that the welding process shall meet the requirements of Section IX of the ASME Boiler and Pressure Vessel Code. So most pipe welding certifications should be to that code. As far as the inspection report goes the specs. (that you don't have) should state if the inspector must meet the requirements of AWS QC1 or a similar requirement. An inspection report could be that you provide a document stating the welds meet the requirements of the code (that you don't have) that you are working to providing you meet the minimal requirements to do so and you actually inspect the work. I'm working on a job under the jurisdiction of the Army Corp of Engineers that requires us to inspect all welds visually and 10% RT and PT. We are doing underground pipe.The AWS QC1 applies to us. A different contractor doing the above ground pipe on the same job has no RT/PT demand and can inspect his own welds visually and the AWS QC1 does not apply to him.

My opinion is that you should send a RFI (Request for Information) to the engineer with a list of questions you need answered. It will eliminate alot of potential and costly problems later.

You could spend alot of money if awarded the job and your interpretation of best commercial practices are different than the engineers.
You have the right to certain information if they want you to enter into a contract.
Good luck Ted