Hello I have to conduct factory inspections of Polyethylene pipe / fittings manufacturers on behalf of my company. The PE products are to be used in natural gas pipeline network. In order to check conformance to relevant standards / best practices, I have prepared a set of questions to ask during inspection. Please guide me on whether the questions are adequate for this purpose, and whether there are more questions I should ask (my remarks on each question are mentioned in double brackets): 1) Do you have an independent Quality Assurance Department? Who do the Quality Assurance personnel report to? ((If QA personnel report to, say, Production Manager, that would show conflict of interest...)) 2) Do you have a Quality Manual (as required by API 15LE)? What details does it contain? Does it also mention the testing frequency and Retest / rejection criteria? ((Any idea about what a manufacturer's Quality manual should contain, e.g., should it include the details mentioned above...)) 3) Are the copies of all relevant standards (e.g. ASTM, API) available with your Quality Assurance personnel? ((If they are to follow the standards, they must have copies of those standards!...)) 4) Regarding conditioning of samples (as required by API 15LE / ASTM D2513), what steps are taken to ensure that the relevant requirements are followed? Do the Quality Assurance personnel always note the ambient temperature / conditioning time (e.g. 1 hr/ 4hrs) in their test reports? ((Even if their lab has an air-conditioner as well as thermometer, wouldn't their QA Engr. have to show that he is actually performing the tests in the required conditions...?)) 5) Is contamination in base resin checked (as per PPI Handbook of PE Pipe 2nd Ed. pg. 121)? ((Is it considered a normal practice to check for contamination? what procedure is used for this purpose...?)) 6) Is melt flow index checked for only base resin or final product as well (as required by ASTM D2513)? ((Why does the Standard mention only the final product and not the base resin that the manufacturer has to check for melt flow rate? Also, why is there no mention of how frequently samples need to be tested for melt flow index...?)) 7) Does the marking / label on fittings contain all the information required by both ASTM D2513 and API 15LE? ((The list of details to be mentioned on fitting markings, as per above standards, seems to be quite long....)) Thanks a lot!!!