In procurement, some products should not be released for shipment only because the supplier says they are finished. Machines, equipment, technical systems, and customer-specific products often need to be seen functioning before they are sent to the buyer, installation site, or end customer.
A Factory Acceptance Test, often called FAT, gives the buyer structured evidence that the product meets the agreed specification before it leaves the supplier’s factory. When a third-party witness is involved, an independent expert observes the test and confirms whether the agreed test procedure has been followed.
This is especially important when the buyer is responsible for delivering equipment to a customer or customer site. If the product fails after delivery, the problem is no longer hidden inside the supplier’s factory. It becomes a delivery issue, a project issue, a customer issue, and sometimes a commercial dispute.
This article explains how FAT and third-party witnessing support procurement decisions, how they affect RFQs and supplier deliveries, and what buyers should define before allowing shipment.
LHTS classification
Role: Tactical procurement
Supporting roles: Operative procurement, Procurement management
Process: RFQ, supplier evaluation, contract implementation, supplier delivery follow-up, quality release before shipment
Level: Advanced
Related course: The sourcing engine room – a modern sourcing process
Quick answer: What is third-party witnessing in a FAT?
Third-party witnessing means that an independent person or inspection company attends a Factory Acceptance Test to observe, verify, and document that the supplier performs the agreed tests correctly.
In procurement, third-party witnessing helps the buyer confirm that equipment or systems function according to specification before shipment. It is especially useful for high-value, customized, safety-critical, or customer-facing equipment where failure after delivery would be costly.
The test is performed by the supplier. The witness does not normally take over the supplier’s responsibility. The witness confirms whether the test has been performed according to the agreed protocol and whether the results support acceptance.
What is a Factory Acceptance Test?
A Factory Acceptance Test is a structured test performed at the supplier’s factory before shipment. The purpose is to verify that the equipment, machine, system, or product works according to the agreed requirements.
For a buyer, FAT is important because a product can look complete without being ready for delivery. The supplier may have finished assembly, painting, packing preparation, and documentation, but the buyer still needs evidence that the product performs the function that was purchased.
A FAT may include:
- functional tests,
- performance tests,
- safety checks,
- control system checks,
- alarm and emergency stop tests,
- interface tests,
- documentation review,
- inspection against drawings and specifications,
- verification of customer-specific requirements.
The key procurement question is not only:
Has the supplier produced the equipment?
The more important question is:
Can the buyer approve this equipment for shipment?
That is why FAT should be treated as a decision point in the procurement process.
Why buyers need to see the product functioning before shipment
When buying technical equipment, the buyer is often not only buying a physical object. The buyer is buying a required function.
A machine must produce.
A pump must deliver capacity.
A control panel must communicate.
A safety function must stop the equipment correctly.
A test system must measure accurately.
A customer-specific product must operate in the way the customer expects.
If these functions are not verified before shipment, problems may appear later at the buyer’s site or customer site. At that point, correction is usually more expensive, slower, and more visible.
A failed function after delivery can create:
- installation delays,
- customer dissatisfaction,
- delayed production start,
- extra travel and service cost,
- rework at site,
- claims and disputes,
- delayed payment,
- damage to the buyer’s internal credibility,
- damage to the buyer’s customer relationship.
FAT helps reduce that risk. It gives the buyer a chance to discover problems while the equipment is still at the supplier’s factory, where tools, technicians, spare parts, drawings, and test equipment are available.
This is one of the main reasons buyers use FAT as a shipment release gate.
What is third-party witnessing?
Third-party witnessing means that an independent party attends the FAT to verify that the test is performed according to the agreed procedure.
The third-party witness may be:
- an inspection company,
- a certification company,
- an independent technical expert,
- a specialist consultant,
- a customer-appointed witness,
- an industry-approved inspection body.
The witness is not part of the supplier’s normal production team and should not be influenced by the supplier’s commercial interest. The value of the witness is independence, technical experience, structured reporting, and increased confidence in the result.
Third-party witnessing is often used when the buyer does not have the internal competence, capacity, or geographical presence to attend the FAT alone. It can also be required by the end customer, by regulation, by industry practice, or by the buyer’s internal risk process.
Why third-party witnessing is used in procurement
Third-party witnessing is used because it gives the buyer independent support at a critical moment in the delivery process.
It helps procurement and technical stakeholders answer questions such as:
- Was the agreed FAT protocol followed?
- Were the correct test conditions used?
- Did the supplier test the agreed product configuration?
- Were deviations documented?
- Were the results measured and recorded correctly?
- Did the supplier demonstrate the required functions?
- Is the equipment ready for shipment?
- Should shipment be blocked until corrective action is completed?
For the tactical buyer, this is valuable because the witness report becomes part of the procurement documentation. It can support the decision to release shipment, hold shipment, request correction, negotiate consequences, or involve the end customer.
Third-party witnessing does not remove the buyer’s responsibility to define what should be tested. A witness can only verify against an agreed scope. If the RFQ, specification, or FAT protocol is weak, the witness will also have a weak basis for assessment.
FAT as a buyer’s release gate before shipment
For procurement, FAT should not be seen only as a technical event. It should be seen as a buyer’s release gate.
A release gate is a decision point. Before the supplier is allowed to ship, the buyer should confirm whether the product has passed the agreed tests or whether open issues must be corrected first.
The release decision should answer:
- Has the product been tested against the agreed specification?
- Were all required functions demonstrated?
- Were performance values measured?
- Were safety functions verified?
- Were customer-specific requirements checked?
- Were deviations documented?
- Are open deviations blocking or non-blocking?
- Has the FAT report been signed?
- Is the supplier allowed to ship?
This is especially important when the product is going directly to a customer site. In that situation, the buyer is not only protecting their own company. The buyer is also protecting the customer delivery, the installation plan, and the commercial relationship.
A good buyer does not ask only: “Is the product finished?”
A good buyer asks: “Have we seen enough evidence to release this product for shipment?”
When should FAT and third-party witnessing be used?
FAT and third-party witnessing are not needed for every purchase. They are most relevant when the risk of failure is high or when the cost of correcting a problem after delivery is significant.
FAT should be considered when buying:
- high-value equipment,
- customized machinery,
- technical systems,
- production equipment,
- automation systems,
- safety-critical products,
- customer-specific solutions,
- long lead-time equipment,
- project-based deliveries,
- equipment from a new supplier,
- equipment from a distant supplier,
- products where failure can stop production,
- products where installation cost is high.
Third-party witnessing should be considered when:
- the buyer lacks internal technical expertise,
- the supplier is located far from the buyer,
- the customer requires independent verification,
- the equipment is business-critical,
- the product must meet strict technical or safety requirements,
- there is a history of supplier quality issues,
- the buyer and supplier may interpret test results differently,
- independent documentation is needed for project acceptance.
For standard catalogue items, low-value repeat purchases, or products with a stable quality history, a full FAT with third-party witnessing may be unnecessary. In those cases, a simpler inspection, certificate review, or pre-shipment check may be enough.
The buyer’s task is to choose the right level of control for the risk.
FAT, SAT, pre-shipment inspection, and third-party witnessing
Buyers sometimes mix up FAT, SAT, pre-shipment inspection, and third-party witnessing. They are related, but they are not the same.
Factory Acceptance Test
FAT is performed at the supplier’s factory before shipment. The purpose is to verify that the product functions according to the agreed specification before it leaves the supplier.
Site Acceptance Test
SAT is performed after delivery and installation at the buyer’s site or customer site. The purpose is to verify that the equipment works in the real operating environment.
Pre-shipment inspection
A pre-shipment inspection usually checks physical condition, quantity, packing, marking, visible defects, documentation, or compliance before dispatch. It does not always prove full functional performance.
Third-party witnessing
Third-party witnessing is not the test itself. It is the independent observation and verification of the test.
A practical way to remember the difference is:
FAT proves function before shipment.
SAT proves function after installation.
Pre-shipment inspection checks readiness for dispatch.
Third-party witnessing gives independent confidence in the test process and result.
How FAT and third-party witnessing affect the RFQ
FAT and third-party witnessing should be included already in the RFQ. If the buyer adds these requirements after the supplier has quoted or after the purchase order has been placed, the supplier may treat them as additional scope, extra cost, or schedule risk.
The RFQ should define:
- whether FAT is required,
- whether third-party witnessing is required,
- whether the buyer or end customer will attend,
- where the FAT will take place,
- what product configuration will be tested,
- which functions must be demonstrated,
- which performance requirements must be measured,
- which standards or specifications apply,
- who prepares the FAT protocol,
- when the FAT protocol must be submitted for approval,
- what test equipment and utilities the supplier must provide,
- what documentation must be available,
- how deviations will be handled,
- whether shipment is blocked until FAT approval,
- who pays for retesting if the product fails,
- who pays for additional witness visits,
- what report must be delivered after the test.
This makes FAT part of the commercial agreement, not only a technical activity.
The RFQ should avoid vague wording such as:
“The supplier shall perform normal testing before delivery.”
That wording is too weak. It does not define what should be tested, how acceptance will be decided, or whether the buyer has the right to stop shipment.
A stronger RFQ requirement would be:
“The supplier shall perform a Factory Acceptance Test before shipment. The FAT protocol shall be submitted to the buyer for approval before the test. Shipment is not permitted until the FAT report is approved by the buyer or until the buyer has given written release.”
This gives procurement a much stronger position if the equipment fails.
What a FAT protocol should include
The FAT protocol is the document that defines how the test will be performed and how the result will be judged. It should be reviewed before the test, not during the test.
A good FAT protocol should include:
1. Purpose and scope
The protocol should explain why the FAT is performed and what equipment, system, or product is included. It should also state what is not included, to avoid misunderstandings.
2. Product identification
The protocol should identify the product clearly. This may include serial number, model number, revision, configuration, drawing number, project number, purchase order number, and specification reference.
3. Test conditions
The protocol should define the test environment and conditions. This can include utilities, power supply, pressure, temperature, software version, test media, tools, measuring instruments, and calibration status.
4. Functional tests
The protocol should list the functions the supplier must demonstrate. This may include start-up, normal operation, stop sequence, control logic, alarms, interlocks, emergency stop, and restart.
5. Performance tests
The protocol should define measurable performance requirements. This may include capacity, speed, tolerance, accuracy, cycle time, output, pressure, flow, temperature, load, or repeatability.
6. Safety checks
Safety functions should be tested where relevant. This may include guards, emergency stops, safety relays, lockout points, alarms, warning signals, and fail-safe functions.
7. Interface checks
Many problems appear at the interface between systems. The protocol should therefore check relevant mechanical, electrical, software, communication, and customer-specific interfaces.
8. Documentation review
The FAT should also verify that the required documentation is available. This may include drawings, manuals, certificates, spare parts lists, calibration certificates, test records, declaration documents, and maintenance instructions.
9. Acceptance criteria
Each test should have clear pass or fail criteria. “Works as intended” is not enough. The protocol should define measurable requirements, tolerances, limits, or documented acceptance rules.
10. Deviation handling
The protocol should explain how deviations will be recorded, classified, corrected, and closed. It should also state who decides whether an open item blocks shipment.
11. Sign-off and release
The protocol should define who signs the FAT report and what the signature means. Does it mean the test was witnessed? Does it mean the product is approved for shipment? Does it mean acceptance with open points? This must be clear.
Typical steps during third-party witnessing
A third-party witnessed FAT normally follows a structured process.
1. Preparation
The buyer, supplier, and witness agree on the FAT scope, protocol, schedule, responsibilities, and reporting format. The buyer should confirm that the product is ready before arranging travel or witness attendance.
2. Protocol review
The FAT protocol is reviewed before the test. This is important because the test should not be improvised on the day of execution. The buyer should ensure that the protocol reflects the RFQ, contract, specification, drawings, and customer requirements.
3. Test execution
The supplier performs the agreed tests. The third-party witness observes the process, checks whether the correct procedure is followed, and verifies that the results are recorded.
4. Deviation recording
Any non-conformity, missing function, incomplete documentation, failed performance value, or unclear result should be documented. The deviation list should be specific and actionable.
5. Result review
The buyer, supplier, and witness review the test results. Open items are classified as blocking or non-blocking.
6. Corrective action
If the equipment fails the FAT, the supplier must correct the issue. Depending on the severity, the buyer may require a full retest, partial retest, document review, photo evidence, video evidence, or new witness attendance.
7. FAT report
The witness or supplier issues a FAT report. The report should include test results, deviations, conclusions, signatures, and any agreed follow-up actions.
8. Shipment release
The buyer decides whether shipment is approved. This decision should be documented. If shipment is released with open points, the open points should have owner, due date, and consequence.
Commercial consequences of a failed FAT
A failed FAT is not only a technical issue. It can become a commercial issue.
If equipment does not pass FAT, the buyer may face:
- delayed shipment,
- delayed customer delivery,
- delayed installation,
- additional inspection cost,
- additional travel cost,
- project penalties,
- expedited freight,
- rework at site,
- customer dissatisfaction,
- delayed payment from the end customer.
That is why the commercial consequences should be defined before the order is placed.
The buyer should clarify:
- who pays for rework,
- who pays for retesting,
- who pays for additional witness visits,
- who pays for extra travel cost,
- whether delivery penalties apply,
- whether payment is linked to successful FAT,
- whether the supplier may ship with open points,
- who approves shipment release,
- how long the supplier has to correct blocking deviations.
For project-based sourcing, FAT is often connected to payment milestones. The buyer should be careful with paying too much before the equipment has passed the agreed test.
A simple principle is useful:
Do not give away most of the commercial leverage before the product has proven that it works.
How to classify open points after FAT
Not every open point should block shipment. Some issues are serious. Others can be solved after shipment without creating major risk. The important point is to classify them clearly.
A practical classification can be:
A-items: Blocking issues
These issues must be solved before shipment. Examples include failed safety functions, missing critical performance, wrong configuration, incomplete control logic, or major deviation from specification.
B-items: Conditional release issues
These issues may allow shipment if the buyer agrees, but they require a clear corrective action plan. Examples include minor software adjustment, missing non-critical documentation, or a function that can be finalized during installation.
C-items: Minor issues
These issues do not normally block shipment. Examples include minor cosmetic issues, formatting errors in documentation, or small labelling corrections.
The classification should be agreed and documented. A vague promise that “the supplier will fix it later” is not enough.
Each open item should have:
- description,
- owner,
- due date,
- agreed corrective action,
- blocking or non-blocking status,
- evidence required for closure.
How this connects to the tactical procurement role
FAT and third-party witnessing are mainly connected to the tactical procurement role.
The tactical buyer is responsible for building the requirement into the sourcing process. This means the buyer should ensure that FAT and witnessing are considered in the RFQ, supplier evaluation, negotiation, contract, and delivery follow-up.
The tactical buyer should secure:
- clear FAT requirements in the RFQ,
- supplier understanding of the FAT scope,
- correct cost inclusion in the quotation,
- realistic delivery schedule,
- buyer or customer right to witness,
- third-party witness option,
- approval of the FAT protocol,
- shipment hold point,
- retesting rules,
- payment milestone connection,
- documentation requirements,
- deviation handling process.
The buyer does not need to be the technical expert on every test. However, the buyer must make sure that the commercial process supports the technical requirement.
In practice, this means procurement should work closely with engineering, quality, project management, production, and sometimes the end customer.
The operative procurement connection
Operative procurement may become involved after the purchase order has been placed. The operative buyer, planner, or order handler may follow up delivery dates, shipping documents, packing instructions, and invoice status.
For operative procurement, the important point is simple:
Do not release shipment, payment, or delivery administration if FAT approval is a required condition and that condition has not been met.
If the purchase order says that shipment is subject to approved FAT, then the operational process must respect that hold point.
The procurement management connection
Procurement management should define when FAT and third-party witnessing are required as part of the company’s sourcing and supplier risk process.
A company may decide that FAT is mandatory for:
- high-value equipment,
- safety-critical equipment,
- new suppliers,
- new technology,
- customer-specific projects,
- products with high installation cost,
- equipment with long lead time,
- deliveries where failure would affect customer commitments.
Procurement management should also ensure that buyers have templates, contract clauses, RFQ wording, and escalation routines for FAT-related decisions.
This turns FAT from an individual buyer decision into a structured procurement practice.
How to source a third-party witness service
When sourcing a third-party witness service, the buyer should not only compare price. The value of the service depends on competence, independence, availability, reporting quality, and understanding of the product being tested.
Important selection criteria include:
Technical expertise
The witness should understand the type of equipment, industry, test method, and relevant standards.
Independence
The witness should be independent from the supplier and have no conflict of interest.
Accreditation and qualifications
Depending on the product and industry, formal accreditation or certification may be required.
Geographic coverage
The witness must be able to attend the supplier’s factory, sometimes in another country or region.
Reporting quality
The report should be clear, structured, factual, and useful for the buyer’s release decision.
Availability
The witness must be available when the supplier is ready. A witness who is technically strong but unavailable at the critical time may delay the project.
Cost structure
The buyer should understand daily rates, travel cost, report cost, cancellation terms, and retest cost.
Liability and insurance
For critical inspections, the buyer should check whether the witness provider has appropriate insurance and liability coverage.
A low-cost witness service may become expensive if the witness lacks competence, misses important issues, or provides a weak report.
Common mistakes buyers make with FAT and third-party witnessing
Adding FAT too late
If FAT is not included in the RFQ or purchase order, the supplier may see it as additional work. This can lead to extra cost, delay, or disagreement.
Accepting the supplier’s standard test without review
A supplier’s standard FAT may show that the product works generally, but not that it works for the buyer’s specific application. The buyer must review the test protocol.
Using vague acceptance criteria
Words like “acceptable,” “normal,” or “works as intended” are often too vague. A good FAT protocol should include measurable criteria.
Sending only procurement to a technical FAT
Procurement should coordinate the commercial process, but technical stakeholders usually need to verify technical performance.
Forgetting the customer requirement
If the product is going to a customer site, the FAT should reflect what the customer needs, not only what the supplier normally tests.
Releasing shipment with unclear open points
Open points must be classified, assigned, dated, and followed up. Otherwise, they can become disputes later.
Confusing FAT with final acceptance
FAT verifies function at the supplier’s factory. It does not always replace installation, commissioning, or Site Acceptance Test.
Paying too much before FAT
If payment is almost complete before the FAT, the buyer may lose leverage when problems appear.
Practical buyer checklist before approving shipment
Before releasing shipment after FAT, the buyer should confirm:
- The agreed FAT protocol was used.
- The correct product configuration was tested.
- All critical functions were demonstrated.
- Performance values were measured and recorded.
- Safety functions were tested where relevant.
- Required documentation was reviewed.
- Deviations were documented.
- Open points were classified.
- Blocking issues were closed.
- Non-blocking issues have owner and deadline.
- The FAT report is complete.
- Required signatures are in place.
- Commercial consequences are understood.
- Shipment release is documented.
This checklist helps the buyer avoid releasing equipment based only on verbal confirmation.
Related course
FAT and third-party witnessing are part of the sourcing process and are especially relevant for the tactical buyer role.
If you want to go deeper into how procurement prepares, negotiates, and implements supplier agreements, the Learn How to Source course The sourcing engine room – a modern sourcing process gives a structured foundation.
The course explains key activities in a modern sourcing process, including preparation, negotiation, supplier selection, implementation, and building a stronger supply chain.
FAQ
What is the purpose of a Factory Acceptance Test?
The purpose of a Factory Acceptance Test is to verify that equipment, machinery, or systems function according to the agreed specification before they are shipped from the supplier’s factory.
What is third-party witnessing?
Third-party witnessing means that an independent person or inspection company attends the test to observe, verify, and report whether the agreed test procedure has been followed.
Is FAT the same as final acceptance?
Not always. FAT is performed before shipment at the supplier’s factory. Final acceptance may depend on installation, commissioning, or Site Acceptance Test at the buyer’s or customer’s site.
Who should attend a FAT?
A FAT may be attended by the supplier, buyer, engineering, quality, project management, end customer, and third-party witness. The exact participants depend on the product and risk.
Should FAT be included in the RFQ?
Yes. FAT should be included in the RFQ if it is required. The RFQ should define test scope, acceptance criteria, witnessing requirements, reporting, cost responsibility, and shipment release conditions.
Can the buyer stop shipment after a failed FAT?
Yes, if the purchase order or contract states that successful FAT approval is required before shipment. This is why FAT should be defined as a shipment release gate.
What is the difference between FAT and third-party witnessing?
FAT is the test. Third-party witnessing is the independent observation and verification of the test.
When is third-party witnessing needed?
Third-party witnessing is useful for high-value, critical, customized, safety-sensitive, or customer-facing equipment. It is also useful when the buyer needs independent evidence or lacks internal technical resources.
What should a FAT report include?
A FAT report should include product identification, test results, deviations, open points, corrective actions, signatures, and a clear conclusion on whether the equipment is accepted, rejected, or conditionally released.
Can equipment be shipped with open FAT points?
Yes, but only if the buyer agrees and the open points are non-blocking. Each open point should have an owner, due date, and agreed corrective action.
Conclusion
Third-party witnessing and Factory Acceptance Tests help buyers reduce risk before equipment is shipped. This is especially important when the product is expensive, customized, technically complex, safety-critical, or intended for a customer site.
For procurement, the key lesson is simple: FAT should not be treated as a late inspection activity. It should be defined in the RFQ, reflected in the supplier’s quotation, included in the purchase order or contract, and used as a clear release gate before shipment.
When done well, FAT and third-party witnessing protect the buyer, the supplier, and the customer. They make problems visible before they become installation failures, delivery disputes, or customer complaints.
A buyer should not release critical equipment only because production is finished.
A buyer should release it when there is documented evidence that it works.
