Site Acceptance Test (SAT)

A Site Acceptance Test is the final formal verification that equipment or a system operates correctly after it has been installed, integrated, and commissioned at the project site, in the actual environment where it will be operated, not the controlled environment of a factory. SAT is a mandatory contract milestone for complex installed systems such as SCADA and control systems, substations, water treatment plant equipment, IT and communication infrastructure, and industrial plant and machinery. A successful SAT is usually the trigger for final payment and the start of the Defect Liability Period (DLP).

What is SAT in government procurement?

SAT follows the Factory Acceptance Test (FAT) and the physical delivery and installation of equipment at site. While FAT verifies that the equipment meets its design specifications in isolation at the factory, SAT verifies that it performs correctly when integrated with all other systems at the actual project location, accounting for real civil infrastructure, actual power supply characteristics, communication networks, ambient conditions, and interface with other equipment.

The SAT procedure is defined in the contract or the SAT protocol agreed between buyer and supplier during the project mobilisation phase. For a SCADA system installed at a water utility's pumping stations, for example, the SAT would include: verifying all remote terminal unit (RTU) communications with the central control room, testing each field sensor and actuator for correct signal range, simulating alarm conditions and verifying their correct annunciation at the control room, testing data archiving and report generation functions, and running the system continuously for a defined period (often 24-72 hours) without failure.

The SAT completion certificate, signed by the buyer's representative and the supplier's commissioning engineer, serves as the formal handover document. It records all tests conducted, results obtained, and any minor outstanding items (punch list items) that the supplier must rectify within a defined timeframe. Major failures at SAT result in rectification, re-testing, and delayed payment.

Many government contracts structure their payment milestone schedule around FAT and SAT: for example, 10-15% on despatch, 70-75% on FAT, and 10-15% on successful SAT and final acceptance. Delays in SAT therefore have a direct cash flow impact on the supplier.

Why it matters for bidders

SAT represents the last checkpoint before the warranty clock starts. Suppliers must ensure that site commissioning is completed properly before scheduling SAT, arriving for SAT with an incompletely installed or untested system is a serious commercial risk. Any defects found during SAT become punch list items that must be cleared before the certificate is issued, during which time the final payment is withheld.

SAT preparation requires coordinating the buyer's operations team (who must make the installed environment available), third party inspection agencies (if required), and the supplier's commissioning engineers. For large projects where SAT covers hundreds of instruments and control loops, the process can take days or weeks. Bidders should build adequate commissioning and SAT time into their project schedule and resource plan.

Suppliers must also be prepared for the buyer to request re-tests of any item that performed marginally during SAT. Maintaining a rigorous commissioning record, with all pre-SAT checks documented, helps defend against unjustified re-test requests.

Example

A state government's IT department procures an integrated command and control centre for a Smart City project, including hardware, software, video management system, GIS integration, and interfaces with 15 city departments. After factory delivery and site installation, the system integrator schedules a 3-day SAT. The buyer's team tests each module: 200 CCTV feeds, adaptive traffic control signals, flood monitoring sensors, emergency response dispatch integration, and the analytics dashboard. On Day 2, a data integration issue with the water department SCADA is found. The supplier's team rectifies it overnight, and the SAT resumes the next morning. On successful completion of all tests, the SAT certificate is signed and the final 15% payment milestone is triggered.

Key rules / thresholds

• SAT is always conducted at the project site after full installation, it cannot be replicated at the factory.
• A signed SAT certificate (or SAT Completion Report) is typically required for the final payment installment.
• Outstanding items after SAT are captured in a punch list with agreed rectification timelines, major outstanding items block certificate issuance.
• The Defect Liability Period (DLP) typically starts from the date of the SAT completion certificate, not the delivery date.