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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
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
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
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.
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
LaboratoryDesign|JAN|FEB 2015 11