You’re three weeks from mechanical completion on a major capital project. The control system just showed up at the site. Within forty-eight hours, your team discovers that half the I/O points don’t match your design documents, the HMI screens reference equipment tags that don’t exist, and the vendor swears everything passed their internal QC. Now you’re staring down a commissioning schedule that just grew by six weeks, burning field labor rates while your project sponsor calculates the change order.
This scenario plays out more often than anyone admits, and proper factory acceptance testing prevents the majority of these failures. Across projects we’ve seen over four decades, a significant portion experience commissioning delays, with equipment problems discovered at the site consistently ranking among the leading causes.
This guide covers what Factory Acceptance Testing actually accomplishes, how to build protocols that catch problems before equipment ships, who needs to witness testing and what they should watch for, and how to handle it when problems surface. We’ll address control systems and safety instrumented systems, remote testing approaches, and industry-specific requirements that trip up even experienced teams.
At Vista Projects, we’ve spent forty years executing integrated engineeringThe process of integrated engineering involves multiple engineering disciplines working in conjunction with other project disciplines to e... across thirteen energy markets. When the same team handles front-end engineering through commissioning, you learn where projects go sideways.
Disclaimer: Equipment testing requirements, industry standards, and costs vary significantly by industry, region, and application. All information reflects general 2025 practices. Verify specific costs, timeframes, and requirements against current conditions before making engineering or financial decisions.
For industrial projects in Canada, FAT plays a critical role in demonstrating compliance with CSA standards and provincial engineering requirements. FAT requirements vary by jurisdiction; confirm compliance with CSA and APEGA standards for Canadian projects.
Documentation generated during FAT supports regulatory submissions and provides evidence of due diligence required under APEGA and other provincial engineering association guidelines.
The Economics of Factory Acceptance Testing
What is Factory Acceptance Testing? FAT is formal verification proving equipment works correctly at the manufacturer’s facility before shipping to your project site. Testing occurs where the manufacturer has expertise, tooling, and spare parts to fix problems efficiently.
Manufacturers offer testing conditions you can’t replicate in the field: calibrated instruments, climate-controlled environments, and technicians who’ve built this exact equipment dozens of times. Your site has weather delays, limited tooling, and teams unfamiliar with the specific equipment.
Why do problems cost more to fix at the site than at the factory? Industry experience suggests field repairs often cost several times more than equivalent factory repairs. The math compounds quickly across multiple factors.
Labor rates tell part of the story. Factory technicians work at standard shop rates, with parts and tools readily available. Field work adds travel days, per diem, premium labor rates, and overtime. A technician who fixes a problem in four hours at the factory might need two days at the site, just accounting for travel, orientation, and permit requirements.
Parts logistics amplify the gap. Factory stockrooms hold components for immediate installation. Site repairs require identifying the failed part, sourcing replacements, arranging expedited freight, clearing customs for international shipments, and waiting while crews stand idle. We’ve seen components worth a few hundred dollars result in total costs many times higher once expediting, freight, and delays accumulate.
The real damage comes from cascade effects. A control system needing rework doesn’t just delay control commissioning. Loop checks can’t proceed until I/O is verified. Functional testing waits for loop checks. Operator training requires functional systems. A start-up depends on trained operators. Each delay pushes everything downstream. For facilities with significant production value, each day of delayed start-up represents a financial impact dwarfing any reasonable FAT investment.
FAT also creates contractual protection that matters later. Witness-signed documentation proves equipment met specifications at shipment. When something fails at the site months later, that documentation determines whether you file a warranty claim at no cost or write a change order from your contingency.
Testing duration varies by complexity. Control system packages often need several days for thorough verification. Instrumented skids might take a day or two. Complex integrated systems can run a week or more, depending on operating modes and interface complexity.
Preparing for FAT Before You Arrive
The work that happens before your team arrives at the factory often determines whether FAT succeeds or fails. Proper preparation prevents the wasted trips and schedule delays that plague projects when treating FAT as a last-minute activity.
Vendor Qualification During Procurement
Effective FAT starts during procurement, not when you arrive at the factory. Vendors vary dramatically in FAT capability and commitment. Some maintain dedicated test facilities with professional procedures. Others cobble together testing at the last minute with whatever instrumentation happens to be available.
Evaluate vendor FAT capabilities before awarding contracts. Ask for sample FAT procedures from previous similar projects. Review their test facilities, instrumentation inventory, and calibration programs. Check references specifically about FAT execution quality, not just product quality. A vendor building excellent equipment but running disorganized FAT creates different problems than poor equipment with professional testing.
Include FAT requirements explicitly in procurement specifications. Define witness hold points requiring your presence before proceeding. Specify documentation deliverables with actual content requirements, not just document titles. Establish calibration standards for test instrumentation. Require pre-FAT readiness verification before confirming travel dates.
Pre-FAT Readiness Assessment
What should be ready before FAT begins? Before committing to travel, verify genuine readiness:
Equipment completion means fully assembled, not mostly assembled. Arriving to find missing components, incomplete wiring, or panels still being built wastes witness team time and travel budget. Require photographic evidence of completion before confirming dates.
Internal testing should be complete with results documented. Vendors should find and fix obvious problems before your team arrives. Your FAT verifies performance against specifications, not whether basic assembly is correct.
Documentation readiness includes finalized test procedures, calibration certificates for all test instrumentation, as-built drawings reflecting actual construction, and any certificates or material test reports your specifications require.
Coordinating FAT with instrument calibration allows you to verify transmitter and analyzer performance before shipment, reducing field calibration workload.
Witness team preparation means your people have reviewed specifications, acceptance criteria, and test procedures before arriving. FAT isn’t the time to read documentation for the first time.
Require a pre-FAT readiness checklist signed by the vendor confirming completion before finalizing travel. Walking into unprepared FAT damages schedules and relationships.
Building Protocols That Actually Work
Generic FAT protocols pulled from previous projects create generic results. Protocols tailored to your specific equipment and project requirements catch the problems that actually matter.
Acceptance Criteria That Eliminate Disputes
Test objectives must trace to specifications precisely enough that pass or fail is obvious. Write specific flow rates, pressures, current draws, and vibration limits with tolerances and measurement standards defined. Reference applicable standards like ISO 20816 for vibration, noting that acceptable values vary by equipment class and operating speed.
Every acceptance criterion needs three elements: measurement method, acceptable range, and test conditions. Vague criteria like “pump operates smoothly” invite disputes where everyone argues for an interpretation. Criteria specifying “bearing vibration below 2.8 mm/s velocity measured per ISO 20816-3 Class I at rated speed and flow” produce clear results.
How should you handle partial results? Build a framework before arriving:
Pass means all criteria are met with documented evidence. Equipment ships without conditions.
Conditional Pass means minor deviations exist with documented resolution plans, responsible parties, and deadlines. Equipment ships with a punch list. Use this category sparingly and only for items genuinely resolvable before commissioning.
Hold means significant issues require resolution and re-verification before shipment. Equipment stays at the factory until it is resolved.
Define category boundaries before testing. Arguing whether a deviation is “minor” or “significant” during FAT, under schedule pressure, with vendor representatives present, produces bad decisions.
Documentation That Supports Decades of Operations
How does FAT documentation support long-term asset management? FAT records become your maintenance baseline for equipment life measured in decades, not project phases measured in months.
As-built drawings verified during testing document the actual installed configuration. These drawings guide every maintenance activity, troubleshooting effort, and modification project for years. Accepting drawings that don’t match physical equipment creates problems that compound over time as maintenance teams work from incorrect information.
Test data records establish performance benchmarks. When a pump starts running rough five years later, comparing current vibration signatures against the FAT baseline data identifies what changed. Without baseline data, troubleshooting starts from scratch.
Calibration certificates and material test reports support regulatory compliance and warranty enforcement. Missing documentation discovered years later during an audit or warranty claim creates expensive problems.
For Canadian projects, FAT documentation supports compliance with CSA standards and provincial regulatory requirements. Engineering review processes should align with APEGA guidelines for Alberta-based projects, with equivalent requirements applying in other provinces.
This documentation must reach operational systems to provide value. Configure asset management platforms to receive FAT data directly. If documentation lives only in project files that close out when construction ends, you’ve lost the long-term value. Test results, calibration records, and configuration parameters should feed maintenance planning, troubleshooting databases, and performance monitoring throughout equipment life.
Coordinating Multiple Disciplines
Factory Acceptance Testing for complex equipment isn’t a single-discipline event, and treating it that way guarantees missed problems.
Electrical engineering verifies that power requirements match site supply, protection coordination works correctly, grounding meets specifications, and heat dissipation stays within enclosure ratings.
Mechanical engineering confirms physical dimensions match installation drawings, access provisions allow maintenance, vibration and alignment meet specifications, and rotating equipment operates within design parameters.
For motor-driven equipment, FAT should include the motor testing procedures that establish baseline vibration and electrical measurements.
Process engineering validates that control logic matches P&IDs and operating philosophy, setpoints and alarm limits reflect process requirements, and sequences execute as intended.
I&C engineering verifies every instrument reads correctly, control loops perform as designed, safety functions operate properly, and communication interfaces work between systems.
Operations representatives confirm HMI presentations support actual shift operations, alarm configurations won’t create floods during normal transients, and control strategies align with how operators will actually run the plant.
Sequence testing logically across disciplines. Verify power systems before energizing controls. Complete I/O point verification before testing logic. Test individual components before integration testing. Document interface responsibilities explicitly so gaps don’t develop between disciplines, assuming someone else covered an area.
Assembling the Right Witness Team
A single witness can’t effectively evaluate equipment spanning multiple disciplines or maintain useful observation across several testing days. One person distracted during a critical sequence misses exactly what causes problems months later.
Who should attend FAT? Team composition depends on equipment complexity, but certain roles matter consistently:
Project engineers verify equipment matches design intent, including the operating philosophy behind specifications. When specifications say “provide flow control,” project engineers know whether that means tight regulation or an acceptable wider variation. They catch deviations that technically meet spec language but miss actual project requirements.
Quality assurance personnel verify that manufacturer procedures meet your quality standards and that documentation is complete and accurate. They watch the process itself, not just results, catching procedural shortcuts that might affect reliability.
Operations representatives catch practical issues that engineering teams miss despite good intentions. They identify HMI layouts that look logical on paper but don’t work for twelve-hour shifts, alarm configurations that will overwhelm operators during upsets, and control strategies that fight how operators actually run plants.
Safety specialists attend to safety instrumented systems, verifying implementation achieves the required risk reduction per applicable standards and jurisdiction requirements.
What to Watch During Testing
Push for complete verification, not just spot checks. See signals across their full operating range, not just convenient test points. Request fail-safe demonstrations showing actual behavior during power loss and communication failure. Verify test equipment calibration certificates before accepting any measurements.
Watch for warning signs indicating deeper issues. Equipment passing specifications but running at limits has no margin for real-world variations. Technicians surprised by results may not have tested this specific unit before your arrival. Documentation changing during testing suggests inadequate preparation. Tests getting skipped “because we’re running behind” should trigger immediate escalation.
Document everything with photos of nameplates and configurations, videos of dynamic tests, and contemporaneous notes. When disagreements arise, capture the issue, specification reference, both positions, supporting data, and proposed resolution immediately while details are fresh.
Control Systems and Safety Instrumented Systems
Control systems and safety instrumented systems demand testing approaches different from those of mechanical equipment. The problems hiding in logic configuration and software settings don’t reveal themselves through visual inspection or simple functional checks.
Control System Verification
Your SCADA software evaluation criteria should inform what you verify during control system FAT. Control system FAT goes far beyond confirming the system powers up and displays graphics. Thorough verification catches configuration errors that otherwise surface during commissioning when corrections cost far more.
I/O verification confirms every point individually: correct signal type, proper scaling and engineering units, accurate alarm setpoints, and appropriate fail-safe states. For systems with several hundred points, thorough verification takes considerable time. Rushing this step is exactly how misconfigured points reach the site.
Logic testing covers every sequence, interlock, and control loop systematically. For control loops: verify manual/auto mode switching, setpoint tracking and response, anti-reset windup behavior, and tuning parameters matching design specifications for sequences: test complete operation from initiation through completion, abort conditions at each step, and timer accuracy. For interlocks: confirm every trip condition, reset requirements, and bypass indication and alarming.
HMI testing verifies operator interface functionality. Displays should match P&IDs accurately. Values should update at appropriate rates. Alarm presentation, acknowledgment, and shelving should work correctly. Security levels should prevent unauthorized changes while allowing operators necessary access.
Integration testing verifies systems work together, not just individually. Test communication between the control system and safety system. Verify historian data collection. Confirm interfaces with third-party packages. The controller works perfectly in isolation, but failing to communicate with other systems creates site problems that component testing never reveals.
For distributed operations, verify that remote SCADA monitoring interfaces function correctly across all communication paths during FAT.
Safety Instrumented Systems
What special FAT requirements apply to safety systems? SIS testing demands additional rigor because failure consequences are severe. These systems exist because hazard analysis determined that safety functions are required. If implementation doesn’t work exactly as designed, the risk reduction you’re counting on doesn’t exist.
IEC 61511 and its Canadian adoption CSA 61511 provide the framework commonly used in process industries. For Canadian projects, CSA standards apply alongside provincial regulatory requirements. Some facilities operate under different standards depending on location and regulatory environment.
Requirements scale with Safety Integrity Level. Lower SIL levels need documented proof test procedures and demonstration of correct safety function operation. Higher SIL levels add diagnostic coverage verification, redundancy testing, and fault tolerance demonstration. FAT duration extends accordingly.
For voting architectures, demonstrate every relevant scenario. A 2oo3 system should show no trip with one sensor in alarm state, trip with two sensors in alarm state, and correct fault handling for sensor failures. Inject actual signals and observe system response rather than reviewing logic on paper.
Test fail-safe behavior explicitly: power failure response, communication loss handling, controller switchover for redundant systems, and network failure modes. Verify the system does what the safety analysis assumes it does.
Safety system requirements change and vary by jurisdiction. For Canadian installations, ensure compliance with CSA 61511 and engage qualified functional safety professionals registered with APEGA or the applicable provincial engineering association.
Handling Problems and Changes During FAT
Finding problems during FAT is success, not failure. How your team categorizes findings, manages changes, and makes ship-or-hold decisions determines whether those problems get resolved efficiently or become site headaches.
Managing Findings Effectively
Every FAT generates findings. Expecting perfect results sets up disappointment and bad decisions. Establish severity categories before testing starts, when judgment isn’t clouded by schedule pressure.
Critical items prevent shipment: safety functions that don’t work, performance significantly below specification, and fundamental design problems requiring engineering changes. These require resolution and re-verification before the equipment leaves the factory.
Major items need resolution before commissioning, but might allow conditional shipment with firm remediation plans. Use this category carefully. “We’ll fix it at the site” often means “we’ll argue about it at the site.”
Minor items get documented and tracked without delaying shipment. Cosmetic issues, documentation corrections, and minor adjustments fall here.
How should you handle design changes discovered during FAT? Testing sometimes reveals that original specifications need modification. The control strategy that looked good on paper doesn’t work in practice. The instrument range specified doesn’t match the actual process conditions.
Manage changes formally, even under schedule pressure. Document the original requirement, proposed change, technical justification, and impact assessment. Get appropriate approvals before accepting modifications. Update all affected documentation before the equipment ships. Informal agreements becoming undocumented changes create commissioning surprises and ongoing maintenance confusion.
Ship or Hold Decisions
Build decision frameworks before testing begins. Define what absolutely requires resolution before shipment. Identify what resources the site fixes would require. Establish who has the authority to make ship or hold decisions. Calculate the schedule impacts of various delay scenarios.
When accepting equipment with open items, document specifics: exactly what remains outstanding, why shipment is acceptable despite open items, resolution timeline with responsible parties, consequences if timelines slip, and re-verification requirements. Get signatures from authorized representatives. This documentation prevents disputes months later about what everyone thought they agreed to.
Your negotiating leverage comes from clear specifications and documented test results. When specifications clearly required specific performance and testing clearly showed a shortfall, your position is strong. When specifications use vague language subject to interpretation, negotiations become difficult.
Remote and Hybrid Approaches
Remote FAT expanded out of necessity during travel restrictions and now has legitimate ongoing applications for certain situations.
Subject matter experts can contribute via video for specific tests without travel costs and time. Extended duration tests, like run-in periods, can be monitored remotely after initial in-person verification establishes a baseline. Follow-up verification of punch list corrections often doesn’t require additional trips.
When does remote FAT work, and when doesn’t it? Remote approaches work reasonably well for observing specific test procedures, reviewing data and documentation, and participating in discussions about findings. They work poorly for assessing physical equipment condition, catching subtle warning signs, evaluating workmanship quality, and situations requiring immediate hands-on investigation.
Limitations are real and significant. Cameras show what vendors choose to point them at. Technical difficulties create observation gaps at unpredictable moments. You miss subtle cues that experienced witnesses catch: technician hesitation suggesting uncertainty, unusual sounds during operation, questionable cable routing, and workmanship.
Hybrid approaches often balance cost and effectiveness. Key witnesses attend critical testing in person, establishing a baseline and catching issues requiring physical presence. Remote participants contribute expertise for specific specialty areas without everyone traveling. Shared documentation and video support coordination between locations.
Test all technology before FAT begins. Assign someone on-site specifically responsible for managing camera positions and ensuring remote participants can see what they need. Establish backup communication methods for when primary systems fail.
Industry-Specific Considerations
Different industries face different FAT challenges based on operating environments, regulatory requirements, and equipment characteristics. What works for standard industrial equipment may miss critical requirements for hazardous service or emerging technologies.
Petrochemical and Refining
Verify hazardous area certifications match your area classification exactly. Equipment rated for less hazardous locations cannot be installed in more hazardous areas without expensive replacement or facility reclassification. Classification systems differ between jurisdictions: NEC divisions apply in the United States, CSA C22.1 (Canadian Electrical Code) applies in Canada, and IEC zones apply internationally. Verify which system your project requires.
Material compatibility verification matters for corrosive and reactive service. Equipment performing perfectly with clean test water may fail rapidly with actual process fluids. Review material certificates against specifications. For critical applications, consider witness of material testing.
High-temperature and high-pressure operating conditions often can’t be safely replicated in a factory. Document clearly what site commissioning must verify, and ensure commissioning plans account for this testing.
Mineral Processing and Heavy Industrial
Focus on mechanical robustness for equipment facing severe service conditions. Establish vibration baselines across full speed ranges rather than single-point spot checks. Baselines support predictive maintenance programs, identifying degradation before failure.
Document the wear component condition before any operation. Initial measurements of liner thickness, impeller dimensions, and bearing clearances establish replacement criteria. Verify spare parts availability and lead times for critical wear items. Some components require months to manufacture, making advance planning essential.
Emerging Energy Technologies
Renewable energy and carbon capture involve technology with less field history than established industrial equipment. Vendors may have limited experience with long-term performance characteristics. Performance guarantee testing takes on greater importance with less historical data available.
Operating conditions for performance guarantees often can’t be replicated at the factory. Solar radiation, wind conditions, and flue gas compositions vary by installation. Document what factory testing can verify and what requires site validation.
Integration with existing infrastructure needs explicit testing for retrofit projects. Legacy systems may use older communication protocols or have undocumented quirks. Test actual interfaces rather than assuming compatibility.
Industry requirements, codes, and standards vary by jurisdiction and change over time. Verify current applicable requirements for your specific project and location.
Making FAT Work for Your Projects
Thorough Factory Acceptance Testing directly impacts project success and long-term operational costs. Money spent on proper verification typically returns through avoided field rework, shorter commissioning schedules, and fewer operational problems over equipment life. Teams executing FAT well generally start up faster and run smoothly. Individual results vary with project complexity and execution quality.
What separates effective FAT from checkbox exercises is continuity and preparation. When engineering teams handle design through commissioning, specifications get written with testability in mind, protocols reflect real requirements, and witnesses understand design intent behind documentation. When FAT is treated as an isolated procurement activity disconnected from engineering and operations, results suffer.
Evaluate your current practices honestly. Where do protocol gaps let problems through? Are witnesses equipped with specifications, knowledge, and decision authority? Does FAT documentation reach systems supporting long-term asset management? Are you qualifying vendor FAT capabilities during procurement or hoping for the best?
Vista Projects brings integrated engineering experience to FAT across energy markets. Our teams handle design through commissioning, connecting specification development to factory verification to site commissioning support.
Disclaimer: This analysis is for informational purposes only and should not be considered engineering, legal, or financial advice. Costs, timeframes, and technical requirements vary significantly by region, industry, and project specifics. Regulations and standards change frequently. Verify current information with qualified professionals and official sources before making project decisions.