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Commissioning: Equipment Start-up & Commissioning

Last month’s column (July, 2011) promoted the idea of having the controls contractor present during manufacturer start-up of major equipment with on-board controllers requiring integration to the building automation direct digital control (DDC) system. 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 on-board equipment controllers and the DDC system.

Historically, commissioning professionals’ participation in equipment start-up 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 start-up is an equipment-based activity, whereas commissioning’s focus is on overall system operation. Although proper equipment start-up is critical for system performance, there is typically minimal value to the owner in paying the commissioning professional to witness the time-consuming contractor’s initialization and troubleshooting of individual equipment components.

  • Major equipment start-up 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 start-up 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 start-up issues have not been a significant source of system performance problems once we get to commissioning functional performance testing.

The increased integration required between equipment controllers and central DDC systems appears to be changing the importance of equipment start-up to overall system performance. Therefore, it is time to reconsider the value of the commissioning professional participating in equipment start-up and what that should entail.

As many people have learned, it is a rare commissioning professional who can simply quietly stand by without engaging in the technical activities taking place. At the very least, we want to ask lots of questions and, at most, we want to request people to do new and different things. 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 start-up plan in place early in construction and, ideally, in the design phase for inclusion in the bid specifications. This plan would identify which equipment start-ups will be witnessed by the commissioning professional and how the commissioning professional will participate. I still 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 impact the standard manufacturer’s start-up 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 start-up procedures in any detail; therefore, “witness only” of those prescriptive activities is probably sufficient. 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.

The real change I am suggesting is incorporating selected system integration checkout and testing elements into the start-up 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 (i.e., system enable, component start/stop, capacity modulation, setpoint resets, etc.) covered by one and only one of the controllers?

It is very easy to find problems with these integration elements later during functional performance testing (and we do find a lot of them), but that is not a good time to discover integration issues. The start-up technician is usually long gone and bringing the technician or someone equally knowledgeable back to the site is very difficult to accomplish. In addition, the very nature of integration deficiencies can result in a long period of finger pointing before real progress is made in resolving them.

Shifting the time and cost associated with functionally testing selected system integration elements to the equipment start-up 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.

 

Commissioning: Getting It Right

Engineered Systems, August, 2011

by
Rebecca Ellis, PE, LEED AP BD+C, CCP, CPMP, CxA
President
Questions & Solutions Engineering
1079 Falls Curve
Chaska, MN  55318
rteesmag@QSEng.com