Large projects add a line to the specification: only manufacturers on the approved manufacturer list are acceptable. It is a condition that directly affects both quotation and schedule.
Why the list exists
The owner or engineering contractor approves certain manufacturers based on experience, to reduce quality risk and avoid repeat problems in the field. The list is usually split by item group, with separate makers for flanges, fittings, valves, gaskets and fasteners.
What changes at enquiry stage
- Price: With competition narrowed, prices are generally higher than open sourcing.
- Lead time: The approved maker's production programme governs, and stock options narrow.
- Item matching: The listed maker may not produce every size and class, which triggers a substitution request.
So it matters to state at the outset whether an AML condition applies and which items it covers.
The substitution process
If supply from a listed maker is not possible, approval is sought for an alternative. The submission typically includes quality certificates (ISO 9001, plus PED or API where relevant), plant and capacity information, references from similar projects, sample certificates and third party inspection history.
Approval can take weeks, and the project schedule must allow for it.
A practical suggestion
When preparing an enquiry list, clarify three things per item: is there an AML condition, which makers are listed, and is substitution approval possible. Settling those upfront removes surprises after the order.
Share your specification conditions and we will price and schedule with suitable manufacturers: enquiry form. See also how to read a mill test report.
FAQ
Does an AML condition affect price?
Yes. With fewer supply options, price and lead time are generally higher than open sourcing.
Can a manufacturer outside the list be used?
Only through substitution approval, with a document package submitted for the owner's review.
What should I state on the enquiry?
Whether an AML applies, the list itself and whether substitution approval is acceptable.
Send us your material list; we reply with price and lead time the same day.
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