Last month’s column (July 2011) promoted the idea of having the controls contractor present during manufacturer start-up of major equipment with onboard controllers requiring integration to the BAS DDC. This month, I’d like to explore the potential advantages and disadvantages of also having the commissioning professional present. This idea is intended to address the recurrent problems we find with the integration of onboard equipment controllers and the DDC system.
BEYOND ‘AS-NEEDED'
Historically, commissioning professionals’ participation in equipment startup has been relatively casual and on a perceived as-needed basis. The commissioning professional was also relegated to a witness-only role. There are a few good reasons for this:- Equipment
startup is an equipment-based activity, whereas commissioning’s focus is on
overall system operation.
-
Major equipment startup is a well-defined process often performed by a
specially trained manufacturer’s representative/technician who travels to the
construction site for a pre-determined, finite period of time to complete
prescriptive startup procedures. We have been informed this does not include
time for much interaction with the commissioning professional or demonstration
of proper operation outside of the manufacturer’s recommended procedures.
- Until recently, equipment startup issues have not been a significant source of system performance problems once we get to commissioning functional performance testing (FPT).
As many people have learned, it is a rare commissioning professional who can quietly stand by without engaging in the technical activities taking place. If the commissioning professional shows up to witness the technician’s work without a prior understanding of roles and responsibilities, there is a good chance the commissioning professional will be perceived as an annoyance and impediment to progress.
Therefore, it is best to have an equipment startup plan in place early in construction and, ideally, in the design phase for inclusion in the bid specifications. This plan would identify which equipment startups will be witnessed by the commissioning professional and how the commissioning professional will participate. I maintain that witness-only participation by the commissioning professional has limited value, so we need to clarify what the commissioning professional will do and how it may affect the standard manufacturer’s startup process.
I recommend that the commissioning professional’s participation be focused on system integration issues. There is little reason for the commissioning professional to question the manufacturer’s official startup procedures in any detail. Of course, if the commissioning professional sees that the manufacturer’s procedures are not being followed or that data is not being properly collected and recorded, that will need to be documented by the commissioning professional and addressed by the contractor.
GETTING THE MOST OUT OF THE PROCESS
The real change I am suggesting is incorporating selected system integration checkout and testing elements into the startup process when both the manufacturer’s technical representative and the DDC contractor are present. For most situations, this will primarily be testing the communications between the on-board equipment controller and the central DDC system as follows:- Are all
of the required points being shared between the two systems and providing
reasonable values?
- Are all
control functions (system enable, component start/stop, capacity modulation,
setpoint resets, etc.) covered by one and only one of the controllers?
Shifting the time and cost associated with functionally testing selected system integration elements to the equipment startup process - with commissioning professional oversight and documentation - should help minimize the total time and effort required for this verification. It should also greatly enhance system performance and reduce the length of the commissioning action list at the end of construction.ES
