Certificate Of Conformance

A Certificate of Conformance (CoC) is a supplier's written declaration that shipped parts, materials, or services meet the stated contract, drawing, specification, and packaging/identification requirements. In federal procurement, an approved CoC can substitute for source inspection when authorized in writing. In manufacturing, it functions as a document-control checkpoint linking a received lot to the purchase order, part number, revision, quantity, and shipment record.

On the shop floor, the receiving and quality-intake team uses the CoC as the first release gate for incoming lots. When a delivery arrives, the CoC is matched against the purchase order, part number, revision, quantity, and packing slip. If these align, the lot can be booked into stock, sent to inspection, or routed to quarantine. The CoC also becomes the anchor for raw material chain-of-custody: date codes, heat/lot numbers, serial numbers, and shelf-life data are attached to it so that FIFO/FEFO control, issue to production, and recall tracing all reference the same document package. For safety-critical, aerospace, or counterfeit-sensitive parts, buyers rely on the CoC as evidence of supplier attestation but still expect supporting records like material test reports and inspection data to be available. A properly filed CoC prevents commingling, expired material issues, and lost traceability.