Laboratory Design Newsletter - January/February 2015

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By: David Wilson, PE, LEED AP, SSOE Group

Commissioning has become an increas- ingly common practice. It’s essentially a formalized functional performance test of an entire building’s systems—a process that validates, verifies and documents the builder’s project objectives have been fully met. Simply put, commissioning independently confirms newly built, renovated or existing buildings work the way they’re supposed to. In addition, retro-commissioning of existing buildings is becoming more common to solve operation problems.

In the ideal world, a round of commissioning should occur after every stage of the project. Ideally, commissioning functional testing would occur before acceptance and then again before the warranty period has expired so any deficiencies could be corrected before the warranty period ends.

The fact is, commissioning can be a tedious job that requires a great deal of time and expertise. Nor is it cheap. So the question then becomes: Is it worth it?

Too often, it’s a process industrial leaders only really know they needed after it’s too late, after things have gone wrong. Investing a little more time in verification can save a lot more time, trouble and money in the long run.

Here are some issues that can be identified through the commissioning process, as illustrated by real case scenarios encountered by an HVAC commissioning expert. Some of these case scenarios involve what was discovered during the testing process, and some involve what occurred for lack of commissioning, along with the steps required to rectify those problems.

UNTRUSTWORTHY FAILSAFE MECHANISMS

At a small lab addition to a manufacturing facility in Malaysia, the contractor claimed to install all the equipment and associated controls. According to the graphic screen displays, the HVAC system was operating correctly. Nevertheless, the facility’s owner found the space temperature parameters weren’t maintained. Troubleshooting revealed the control wiring hadn’t been installed for one control valve. Hence the system lacked the necessary feedback loop to confirm that valve was functioning correctly.

Everything turned out fine, but had this HVAC system been fully commissioned, this problem would’ve been quickly and easily caught before the building became operational, saving time and trouble. Commissioning would’ve saved the owner the time and associated costs of staff required to troubleshoot and correct the issue. The issue took about three weeks of meetings and investigation to troubleshoot and correct the issue. Three weeks of owner use of the space was lost due to the high-temperature issue. In addition, this situation also could have resulted in three weeks of lost production for the manufacturing facility.

In a similar scenario, an air-handling unit with three cooling coils wasn’t keeping its building cool enough. When experts looked at the system as a whole, it told them everything was functioning correctly. But upon examination of each coil individually, the trouble shooters realized the airflow was grossly uneven. One coil was receiving too much air, while another was receiving far too little.

When the system had assessed itself, it averaged all the cool air among the three coils together and concluded it was functioning well. But the lack of air conditioning in the building told a different story. Only by looking at individual data from each of the three coils could the problem be diagnosed.

To rectify the problem, a construction team had to modify ductwork and make additional invasive changes. Commissioning would’ve identified the problem before acceptance by the owner. The issue caused many complaints from the users and higher energy costs. Energy savings and trouble would’ve been eliminated had commissioning occurred. Note the owner originally had commissioning in the project scope, but eliminated it to save money when the project bids were received.

DOCUMENTATION

Commissioning not only involves testing, but also provides documentation that can serve the building’s operators for years to come, as illustrated by the next case scenario.

A large lab building on a university campus was constructed in phases. The core and shell were built first, and then each of five up-fit floors were built as separate fit-out packages. Air-conditioning systems were added as the up-fits occurred, over a period of several years. As each additional floor was added, the systems needed to be rebalanced and the control system’s set points needed to be re-adjusted, but the challenge was keeping track of the set points. Each time the control system software needed to be updated, no one could find the documentation detailing the set points. They ultimately had to be recalculated and adjusted to accommodate the new up-fit. In the confusion, incorrect set points were used, causing operational problems for lab ventilation systems, fume hoods and smoke alarms.

This was an ongoing problem for the facility, and cost thousands of dollars over a four-year period. Had commissioning been part of the

Should your project undergo commissioning?

SSOE performed commissioning services for this LEED manufacturing facility. Commissioning confirms proper operation of systems and ideally would occur as part of each phase of the project from design through acceptance of the building. This will eliminate any issues that could result in time and effort spent to correct issues or potentially affect production. Image: DTXphotography.com by Jonny Carroll