Runoff and Buyoff

The two-stage structure exists because moving a line breaks things. Works runoff proves the equipment functions before it is dismantled and shipped; site runoff proves it still functions after reassembly, on the customer's utilities, with the customer's parts. Passing the first is no guarantee of the second, and the gap between them is where schedule risk concentrates.

Buyoff matters commercially because it usually releases money and starts clocks. A payment milestone is frequently tied to works buyoff, and the warranty period commonly starts at final buyoff rather than at delivery. On a project with a long commissioning phase, that difference can be a year of warranty exposure that was never priced.

The clause worth finding in any specification is the one listing what must be demonstrated. A runoff that requires only functional operation is a different exercise from one requiring a sustained rate trial and a capability study with the customer's engineer present for a week. Both get called runoff, and they are not the same cost.

The two stages, and what each usually requires

• Works runoff: at the supplier's facility, on the supplier's utilities, often with sample parts rather than production material.
• Works buyoff: customer sign-off releasing shipment, and frequently a payment milestone.
• Site runoff: after installation, on the customer's utilities, with production material and production operators.
• Final buyoff: formal acceptance. Commonly the event that starts the warranty period rather than delivery.
• Punch list: outstanding items agreed at buyoff, with dates. What is on it and who closes it is worth pinning down.