commissioning process, plants can help
eliminate the challenges inherent in nontraditional systems.
Commissioning is such a valuable
tool for ensuring that mechanical systems
operate as efficiently and environmentally
friendly as possible that the process is
recognized by the U.S. Green Building
Council’s LEED® (Leadership in Energy
and Environmental Design) certification
program. The 2009 version of LEED for
New Construction has provisions that
impact whether or not and how central
energy plants must be commissioned (see
“LEED + District Energy” column on p. 51.)
Courtesy RMF Engineering Inc.
It is advisable to test switchgear during central energy plant commissioning to ensure that it meets
InterNational Electrical Testing Association (NETA) standards. NETA testing is being conducted at this
plant to ensure the integrity of the equipment prior to placing it into service.
fact, a process called ‘retrocommissioning’
dedicated to commissioning existing
facilities. Retrocommissioning involves
analyzing an existing plant’s operation
in order to understand how the facility
was originally intended to operate and
to compare that against how it currently
operates. Generally speaking, only a few
years after startup, most utility plants
need to make changes in their operation
to keep pace with their customers’ changing needs. Retrocommissioning enables
existing plants to optimize their efficiency
while also optimizing their function to
meet new end-user requirements.
Retrocommissioning enables
existing plants to optimize their
efficiency while also optimizing
their function to meet new
end-user requirements.
Whether new or existing, plants that
have nontraditional systems may find
commissioning to be especially valuable.
A traditional plant might be described
as one having four evenly matched boilers
or chillers arranged in a conventional
manifold system that operate on a classic
control sequence. Operators and owners
are familiar with these systems and typically have a great understanding of how
they should operate. In contrast, a nontraditional system is one that is designed
and intended to operate outside of the
standard modus operandi.
One nontraditional system currently
undergoing commissioning is a boiler
plant comprising 15 10,000-lb/hr (300
HP) boilers, all interconnected to act as
a single 150,000-lb/hr boiler with a single
control panel controlling 30 different
firing rates. The plant owner chose this
configuration based on data suggesting
that this arrangement would generate a
higher operating efficiency than a traditional plant. Commissioning will enable
the owner to verify or disprove this claim.
Other nontraditional systems that
could benefit from commissioning might
include plants using alternative fuels or
those having multiple capacity equipment
installed – which presents challenges with
equipment staging, water balancing and
operator training. By implementing the
Commissioning Levels
Different levels of commissioning
can be performed at central energy plants,
depending on the plant owner’s unique
needs. When deciding whether or not to
commission a project, plant owners should
ask what it is they want the process to
do for them: Perhaps simply to test the
systems to ensure proper operation? Or
for assurance that a plant design is sound
and the documents coordinated such
that plant construction can be bid with
clarity and therefore minimal bid-related
change orders?
Though the various potential levels
of commissioning services have not been
formally defined in ways that are accepted
and used uniformly across the industry,
that may be changing. The U.S. Green
Building Council is the first industry
group or program to try to establish any
‘standard’ commissioning levels. Its LEED
certification program describes two levels:
fundamental and enhanced commissioning.
Fundamental commissioning is a
certification prerequisite focused on the
plant construction phase. It consists of
the commissioning agent providing
installation checklists, functional testing
and a final report summarizing how the
systems operate and any recommendations for system improvements.
Enhanced commissioning, worth two
additional points toward LEED certification, emphasizes commissioning activities
during the design phase as well. Building
on the fundamental commissioning
requirements, this level requires that
the commissioning agent provide at least
one design phase review of the construction documents, preferably at the design
