The Value Of Factory Witness Testing
There are many benefits to requiring FWTs, but like pretty much everything else, there are associated costs.
The manufacture of most equipment includes various levels of quality control including inspections, verifications, and other quality control processes as part of their overall quality assurance programs. Most large infrastructure equipment such as chillers, generators, and UPS systems are subjected to some manner of operational testing prior to shipment. Even so, it is not uncommon for manufacturing defects, assembly errors, and other discrepancies to slip through. Specifying more stringent and project specific inspections, certifications, and testing is referred to as factory acceptance testing. When the owner also requires these tests and inspections be witnessed by their project team this becomes known as factory witness testing (FWT).
There are many benefits to requiring FWTs, but like pretty much everything else, there are associated costs. The overarching justification for doing FWTs is that any issues or discrepancies identified at the factory can be much more easily resolved prior to shipment than after the equipment arrives on-site. The decision to include FWTs in the purchase of equipment should be based on what value-add the FWT provides, the risks of not doing FWTs, and the costs (in both time and money) of performing the FWTs. In general, requiring FWTs for simple, mass-produced and standardized products with short or no lead times would be overkill. On the other hand, complex, customized, and long lead time equipment can be good candidates for FWTs. An excellent example would be switchgear. If the switchgear is standard without any complex controls, then maybe FWTs would not add much value. If the switchgear is for paralleling multiple generators and includes closed-transition between utility and generator sources with an integral PLC controller and site-specific sequences-of-operations, then requiring FWTs are certainly appropriate.
Another consideration is what tests are you trying to have performed compared to the suppliers testing capabilities. When manufacturers have their own test facilities and trained staff and are used to providing FWTs as a routine part of their service offerings, you will typically get better results for less costs than when manufacturer’s need to engage third-party testing facilities. In these situations, the manufacturer will incur costs for shipping the equipment to the test facility, rental of the facility, and associated staff for performing the testing, and the additional time to coordinate and communicate the test requirements and associated scheduling challenges.
Once the decision is made to require FWTs, the project team needs to develop clear and detailed FWT specifications to ensure all parties agree with what the FWT entails. This should include any testing standards that may apply (ANSI, ASHRAE, AHRI, IEEE, NFPA, SMACNA, etc.), load profiles, durations, simulated conditions, etc. When ambient test conditions are specified then the equipment must be tested within environmental test chambers, which increase FWT costs where this is even feasible depending upon the size and capacity of the equipment.
On a past project the chiller specifications required the manufacturer to include FWTs. The manufacturer interpreted that to mean the owner’s team would visit the factory (in Mexico), go on a plant tour, and then watch the chiller run. The acceptance criteria was “if it runs for 20 minutes without tripping on a safety then it passes.” When the project team clarified that the expectation was for the chiller to operate at various loads and transients, be tested for energy efficiency per AHRI standards, etc., the manufacturer stated the unit would have to be shipped to a third-party test facility (in Michigan), the delivery date to the site would be pushed back a month, and there would be a $50K changeorder.
Participants in FWTs should include at least one representative for the owner, the facilities management staff, the engineer-of-record, the general contractor (GC), the commissioning agent (CxA), the subcontractor responsible for receiving and installing the equipment, and in most cases, the controls contractor. The facilities staff will get the opportunity to physically see the equipment in operation and make contacts with the manufacturer’s application engineers for future technical support.
The engineer-of-record can ensure the manufactured equipment matches what was submitted and that the demonstrated performance satisfies the specification. The GC can inspect the equipment to ensure they understand what accommodations the equipment will require for installation and discuss delivery, storage, and other logistical details and plans for shipping and delivery. The installing subcontractor can verify dimensions, type of connections, clearance requirements, etc., to help facilitate a quality install. If the equipment will be integrated into a BAS, as it almost always will, then the BAS controls contractor should participate to ensure they have all the necessary information and understanding of what protocols, hardware, and interfaces are necessary for seamless controls integration. The CxA typically leads the testing from the owner’s perspective and oversees the manufacturer’s execution of the FWT. The CxA also documents the FWT, captures all relevant comments, discrepancies, issues, etc., and issues a FWT report. The owner should also be present to get a first-hand understanding of all that transpires in case subsequent decisions are required regarding any recommended changes, compromises, or project-related impacts that may arise from the FWT.
In some situations, the project team may need to supply “owner-provided” ancillaries and devices to the manufacturer to facilitate the required testing. This could include control sensors, valves, dampers, actuators, meters, or other components that are not provided by the manufacturer as part of the equipment package. This adds complexity and costs to the FWT, requires additional coordination, and may entail some liability issues.
The costs associated with requiring FWTs can vary greatly based on a myriad of factors. These include the inherent capabilities (or lack thereof) of the factory to perform the required tests. Other factors include whether the required tests are at standard test conditions or if the test facility needs to be able to accommodate site specific test conditions. Obviously, the quantity of equipment being tested has a large impact on costs. For projects that will use several or more same or similar units (such as air-handling units) you can maximize the benefits of doing FWTs while also minimizing costs by specifying that only one of the units undergo FWT. Another cost-saving compromise can be to test at standard conditions and then have the application engineers extrapolate these test results to demonstrate compliance with site-specific conditions with the engineer-of-record’s review and approval.
Another sometimes overlooked cost is for the travel and living expenses of the project team. In many cases these costs are included in the overall pricing from the manufacturer but not always. This needs to be clearly understood and spelled out in the contract documents.
One last comment on FWT costs: When FWTs are specified and included in the equipment bidding phase, the costs are typically much less than when the equipment has already been purchased and requesting pricing for a FWT is considered a changeorder.
In all my experiences doing commissioning I have never been on a FWT where significant issues were not encountered. I witnessed a 900-ton centrifugal chiller (that had passed every internal QC check and was otherwise ready for shipment) run backward due to crossed electrical leads internal to the unit. I have seen a UPS unit with “aluminum conductors” that were clearly prohibited by the purchase specification. I’ve seen compressors fail, control interface problems, and all manner of discrepancies. In most cases, the discrepancies are somewhat minor and easily resolved at the factory, but occasionally the discrepancies are much more serious such as generator fuel oil leaks, left-handed vs right-handed HVAC coil connections, conduit connections from the bottom where top connections were expected, etc. In many cases the knowledge gained by the installing contractors regarding the nuances and specifics of the equipment can alone justify the costs by ensuring a smooth installation and startup of the equipment after receipt.
So, the value of FWTs depends upon how well the FWT is planned, specified, and executed. It depends on who attends, what capabilities the testing facility has, and the stringency of the tests performed. In large part the success is dependent upon how well the project team’s expectations are communicated to the supplier, manufacturer, and the testing staff to ensure everyone agrees with the testing goals and objectives, acceptance criteria and/or certifications, and durations.