The lowest unit price is only comparable when the supply scope is the same. Before comparing totals, put each quotation against one approved item list and drawing revision.
Build one comparison sheet
Use one row per item: product type, material grade, standard and edition, all connection sizes, wall thickness or rating as applicable, quantity, and drawing reference. Keep substitutions and exceptions in a separate column. Do not treat a blank field as confirmation.
Compare what the price includes
Ask whether machining, surface treatment, inspection documents, packaging and any requested third-party inspection are included. Separate product price from freight and other delivery charges. Record the currency, quotation validity, agreed trade term and named destination; a port name alone does not define the complete delivery arrangement.
Resolve technical differences before ordering
If one offer proposes a different material, flange face, wall thickness or connection, send the difference to your project engineer. A lower-priced alternative is not automatically equivalent. Keep the supplier’s written answer with the purchase order, rather than relying on an informal message that is absent from the final specification.
Questions buyers often ask
Can two offers be compared by weight alone? No: weight does not establish the same material, dimensions, inspection scope or documents. What should be sent for a revised offer? Send the common item list, changed quantities, accepted drawing revision and a clear list of open points.