of actual construction. Many different
individuals have a hand in the planning
process – each of whom has a different
background and vision of how the completed facility should look and function.
While many of the individuals tasked with
planning and building the plant have a
basic understanding of how it should
function, most have never operated one.
A commissioning agent brings to
the table a team comprising both individuals who understand how to design
and plan a facility as well as others who
know what it takes to operate one efficiently. The latter consists of former plant
operators and supervisors, people with
controls contractor backgrounds, and
test and balance contractors. Coming
together with the commissioning agent
provides the opportunity for designers
and operators to learn from each other,
in addition to benefiting from the agent’s
third-party commissioning consultation.
This scenario enables designers, for
example, to be educated on the importance of head space around the backside
of a boiler or chiller and operators to
learn how and why a system was installed
and intended to operate.
Identifying Performance Issues
Not only will commissioning improve
the planning, design and construction
phases, but, through the use of functional
performance testing, it will also identify
those issues that operators will eventually
find – as well as those issues that operators may not.
Such is frequently the case, for
instance, with commissioning chilled-water systems. These systems are often
installed with a secondary pumping system
controlled by variable-speed controllers,
controlled in turn via a series of differential pressure sensors. While this part
of the system is usually installed correctly
– and operators learn rather quickly if it
works or not – the variable-speed drive’s
bypass is often overlooked! During commissioning, it is not uncommon to discover that when the drive is put into
bypass, the motor immediately begins to
spin backward! Although this is a simple
installation issue caused by the contractor
having crossed two wires, it is something
that the operators typically don’t discover
until there is an emergency and they need
Courtesy RMF Engineering Inc.
Verifying the function and installation of equipment before startup is an integral part of commissioning.
Here a commissioning agent is checking that the drawout-style electrical breakers are installed properly.
to use the bypass. Commissioning can
surface this problem well beforehand.
Through functional testing and systems training tailored for facilities operators, the commissioning agent can help
operators understand, for example, why
designers installed three pumps and two
flow meters instead of three and what to
expect when one of the pumps fails. This
was the case in one project commissioned
by RMF Engineering. In this instance a
chiller was added to an existing system,
and the designers added two new pumps
to serve the new chiller and replaced
the pump serving the existing chiller to
compensate for the additional pumping
head being introduced to the system.
The system was designed so that one of
the new pumps for the new chiller was
to run all the time, while the other standby
pump was to operate only in the event
the primary pump failed, thus establishing
a solid level of redundancy. Two flow
meters were installed in lieu of three,
one at each chiller, for the purpose of
monitoring flow to each chiller instead
of the flow through the pumps.
More important, the commissioning
agent can help facility operators understand what and how the data is being
pulled out of the supervisory control and
data acquisition (SCADA) system and use
it to make an informed decision on how
to operate the plant more efficiently. The
SCADA system compiles real-time information from the various sensors and
meters throughout the plant and presents
it in a format that can be easily understood by plant operators.
Another often-overlooked and
potentially even more costly concern is
whether the over-current protection is
properly adjusted for the bypass. Nine
out of 10 times when checked during
commissioning, it is found set at the
factory default setting and has not been
Commissioning can identify
issues while the contractor still
owns the equipment – and
before operators discover them
during an emergency.
