Commissioning laboratory facilities:
What are you trying to prove?
By Tim Horrocks and Maurice DeFeo
As security concerns continue to be at the forefront of our national consciousness, it is becoming increasingly important to find ways to ensure that critical facilities remain functioning during an emergency. The growing trend of building commissioning addresses just this, particularly in animal research facilities and high-containment laboratories (laboratories rated at biosafety levels 3 and 4), which play an important role in our national security. In fact, new National Institutes of Health (NIH) building requirements always include commissioning.
Ideally, commissioning includes not only monitoring with the building automation system but also on-site observations in the mechanical room(s). Photo ŠTom Bernard, courtesy of CUH2A.
R&D facilities within the private sector are on a parallel path of increasing commissioning to improve their own protocols that hasten their products to market. Before drugs can be marketed for consumption by the general population, they must meet or exceed the Food and Drug Administration’s stringent requirements for approval. The FDA requires that many systems be validated, and commissioning is often a first step towards meeting this requirement. Another growing trend, Leadership in Energy Efficient Design (LEED) certification, also requires some commissioning to assure more efficient building operations.
What is commissioning? ASHRAE, the American Society of Heating, Refrigerating, and Air-Conditioning Engineers, defines commissioning as “the process of ensuring that systems are designed, installed, functionally tested, and capable of being operated and maintained to perform in conformity with the design intent.” Within the parameters of this generalized definition, various interpretations exist regarding the specifics of commissioning. What comes to mind first for many when they hear the term is verification of technical parameters, such as temperature setpoints, relative humidity, air change rates, air pressurization, and particulate counts (for cleanroom environments).
General life safety issues are also common targets of commissioning. For example, provisions for fire and smoke containment can be tested for adherence to applicable requirements and correct functioning. Also, operational issues can be examined, including proper functioning of fume hoods and biosafety cabinets. Some commissioning may be required in non-laboratory spaces as well, such as commissioning to ensure the correct operation of smoke evacuation systems in atriums and lobbies.
Why commission? Laboratories are expensive to build, and a large portion of the initial project cost for MEP systems—30 to 40% or more—includes high-cost, high-quality equipment to provide redundancy for critical components. In some cases, this initial investment will be devalued or even lost if the systems fail to operate as intended.
For example, if an HVAC system fails to continuously maintain a desired temperature and humidity level, animal studies, FDA clinical trials, and other scientific research will become null and void. In these cases, commissioning is essential, and the value it provides far outweighs the cost of commissioning. The risks in lost time, money, and knowledge associated with not commissioning are far too great; skipping commissioning is not a viable option.
Who should commission? For best results, commissioning requires a well-thought-out plan. To achieve this, leading project team members should all be represented on the commissioning team, and their roles should be clearly defined.
The architecture/engineering firm is best equipped to guide the owner through the integration of the MEP systems and to fully explain their role in the design intent and operations of the facility. The owner’s maintenance engineers, who are often overlooked, should also be included in the process. These engineers have a day-to-day understanding of the mechanical systems and can provide invaluable insight into what realistically can be expected over the long term. The construction manager (or general contractor) and the subcontractors play the largest role in ensuring that systems are installed, functionally tested, and operated in compliance with the design intent.
The A/E is best-suited to lead the commissioning process since it is the responsibility of this firm (or firms) to coordinate the owner’s requirements, the maintenance engineers’ suggestions, and the field installation issues that impact system function.
Cage/rack and tunnel wash with autoclave. These are all important components of a laboratory and should be thoroughly tested. Photo ŠTom Bernard, courtesy of CUH2A.
One of the more important decisions is to identify what should be, and what should not be, commissioned. This begins with the A/E and owner reviewing the project and identifying those systems that are critical to the facility’s operation and scientific mission.
Once these systems are identified, the A/E and the owner need to determine the appropriate sample rate for each. For example, in an ABSL-3 area, it is important to commission all of the terminal control boxes, while in the support areas of the same building only a small percentage of these terminal control boxes would require testing. The sampling rate is important because commissioning takes time, and time is money.
During commissioning testing, a prudent commissioning agent will not only observe the operation of the relevant equipment through the building automation system (BAS), but will also observe the spaces being monitored physically with local instruments to ensure compliance with the A/E’s design intent. This additional check often reveals failures, including miscalibrations of the installed sensors or equipment.
The process of commissioning a building’s mechanical systems often leads to a fine-tuning of the building. For example, in a laboratory suite served by two exhaust fans, the system must be programmed so that upon the loss of one fan, the other fan ramps up fast enough to maintain containment. Very often, the initial timing of the secondary fan ramp-up must be adjusted to maintain the desired containment. This is especially critical for high-containment laboratories rated BSL-3 or -4. Because each building is unique in the layout and requirements of the mechanical systems, it is not uncommon to perform this test a number of times to find the correct sequence for each building or space.
How to commission? The two most important systems to cover during commissioning are the system integration plan and the critical system plan.
The system integration plan is the testing of the system in its normal, failure, and emergency power modes. “Normal mode” refers to the system operating to maintain temperature, humidity, and pressurization. “Failure mode” refers to failures such as a fan belt breaking on an exhaust fan. The back-up fans should start automatically, the fan with the broken belt should turn off, and although the space might experience a small change in pressure, it should recover quickly. “Emergency power mode” refers to a loss of power to the building, in which all the MEP systems start to ramp down to a stop position. The coordination between the emergency generator and scientific equipment, and determining what equipment to start first, is critical.
Equipment supporting life safety is required to start in as short a time as 10 sec, depending on the authority having jurisdiction. The process of restarting life safety systems first and then restarting other building systems is time-consuming; however, a good commissioning plan can cut down this time considerably.
During a complete power failure, before the emergency generator can start, every piece of mechanical equipment without uninterrupted power source (UPS) back-up is effectively shut down. Although the disconnect from power to emergency power can be as short as 3 to 5 sec, there are large pieces of mechanical equipment that are now running on momentum, and need to be restored to power, in the proper sequence, to maintain the design intent. The spaces where negative pressure is required should have their exhaust fans indexed up first, before their associated supply fans return to normal operation.
The critical system plan ranks spaces from most critical to least critical. By identifying the relative importance of each space, the system can be designed so that spaces that fall into the “most critical” column are kept as close as possible to design conditions, whereas the environment in less critical spaces can be sacrificed.
For example, emergency power (EP) for a laboratory suite is essential. Research requires reliable fume hoods, biosafety cabinets, freezers, and rack, cage, and glass washers. These are all important components of a laboratory and should be thoroughly tested. Other less obvious conditions are also often observed during the commissioning process—conditions which otherwise may have gone unnoticed.
During an EP simulation at an important government research facility, we at CUH2A ran across just such a condition. Two boilers were designed to provide steam for the building, primarily for the cage and rack washers, each at 100% of the required load. A lead/lag control was set up to exercise each of the boilers for equal run time.
During the EP simulation, it was observed that at the time of the simulated power outage, the EP boiler, through its natural exercise period, was on lag time. This caused the boiler that was designed to provide steam to the facility during a power failure to light up to meet pressure, turn off when pressure was met, light up again when pressure failed and so on. Engineers do not like firing up boilers and turning them off suddenly! An adjustment was made to the controls so that during an EP situation, the boiler on EP would automatically become the lead boiler. The adjustment was a very easy and inexpensive programming revision guaranteed to extend the life of the boiler.
Hurdles to commissioning The two most common barriers in commissioning a building are time and money. If a realistic plan is not in place, complete with important milestones, then items begin to slip at the completion of construction, leaving too little time for accurate and thorough commissioning.
Rushing the commissioning process results in omitting tests for systems originally intended to have been commissioned and also to inferior results for those systems that are tested. This is unfortunate. Without adequate time, the value of commissioning is dramatically diminished, although the process is still expensive. In other words, without adequate time, the owner will not get the expected “bang for the buck.”
Another barrier related to scheduling is that a compressed time frame often leads to less training of maintenance and operations personnel in the running of the systems and in their understanding of the significance of new alarms and the correct response to them. Often, maintenance and operations personnel require training to be able to react more quickly than they needed to with previous equipment.
Regardless of the design, control sequences of mechanical equipment are often installed hastily with the intention of fine-tuning them after installation to meet the design intent. This becomes more complicated when a large building containing multiple spaces is concerned, such as when vivarium, laboratory, office, amenity, and shop spaces all rely on each others’ systems. During the commissioning process, the most common failures occur with the building automation systems’ software sequences. Fortunately, they are also the easiest to adjust.
Electronic technology has come a long way in the past decade; however, differences between digital and analog controls continue to work against each other. It is common practice to control temperature setpoints from exhaust ductwork sensors, while still monitoring and displaying the temperature from a room sensor. This “disconnect” often leads to a disparity between the two sensors, and inaccurate recalibration of one of the sensors, causing confusion. Unfortunately, the sensor viewed by the researcher is often the less accurate one. Efforts are being made to share this data between the two sensors and to control design setpoints from a single source. Laboratory facilities will be better served when this feature is available.
The future of commissioning Currently, varied organizations use varied commissioning models. However, as commissioning becomes more common, we are seeing a shift away from these models toward plans that are tailored specifically to our clients. Because the A/E team is fully versed in the design of the facility—after all, they designed it!—more and more they are taking a lead role in commissioning.
Timothy A. Horrocks is an engineering designer and Maurice DeFeo is an HVAC engineer and associate, CBCP (Certified Building Commissioning Professional). Both work in the Princeton, N.J., office of CUH2A (www. cuh2a.com).
