Monday, 07 June 2010 17:38 Last Updated on Tuesday, 08 June 2010 01:35

Often the terminology related to "commissioning" is misapplied: commissioning, RETRO-commissioning, and RE-commissioning.

• Building Commissioning (Cx) is the generic reference to Cx but is typically referring to new construction Cx.
• Retro-Cx is the commissioning of an existing building that has never been Cx or re-Cx previously.
• Re-Cx is on an existing building that has been either Cx when it was constructed or has previously been retro or re-Cx.

The skills needed for a Cx Authority / Agent (CxA) are different when conducting New Building Cx versus Existing Building Cx, especially if it is retro-Cx compared to re-Cx because the Cx documentation exist and possible a re-Cx plan as well. Although similar, the fundamental differences between new building and retro-Cx for a CxA are the goals / objectives and the immediate availability of the Architectural, Engineering and Contracting (AEC) resources and owner's development team. We will consider the following items when evaluating the CxA skill differences:

• Owner's Project Requirements (OPR)
• Basis of Design (BOD)
• Design phase interaction
• AEC resources
• Facilities and operations management expertise
• Investigation skills
• Owner's retro-Cx goals

During a new construction Cx endeavor, the CxA has the benefit and is typically involved in the development and review of the Owner's Project Requirements (OPR), Basis of Design (BOD), and design development documents (DDs). The OPR and BOD documents provide guidance throughout the design phase for the team, which includes the owner's representative(s), to develop the final construction documents (CDs); the underpinning of how the building will be built. The CxA's direct knowledge and interaction during design phase provides them with insight that does not exist or is not available in retro-Cx.

The CxA has this team, along with the newly engaged contracting team, and interacts regularly with them during the construction implementation. The CxA gains the benefit of the interaction, dialog and understanding of why specific decisions, changes, and other alterations were made throughout the design and construction phases. The availability of these resources to inquire, clarify, and gather specifics about the project is not available in retro-Cx.

At the time a CxA engages in a retro-Cx job it could be years after the above mentioned team has been disbanded. Design and construction documentation may no longer be available, let along exist. Furthermore, the functional use of the facility may have changed numerous times through the life of the facility. It is the CxA's task to investigate, gather information, rebuild the original OPR & BOD intent in comparison to what they should be today, piece together the system / equipment changes and current functionality, attempt to understand the reason why the changes were made, understand how it all impacts the physical assets as it relates to the current functional use, and synthesize everything into a Retro-Cx Plan. Implementing this Plan that should will bring the building systems to the most optimal state possible. The retro-CxA is basically a "forensic investigator" combined with a CxA.

The owner's goals of retro-Cx may differ and need to be considered by the CxA when investigating and piecing together the Cx Plan. RD3 Sustainable Solutions has been engaged by owners to retro-Cx an existing building with the primary task to reduce energy costs, or to optimize performance based on operations and functional use with little emphasis on energy consumption, or a comprehensive retro-Cx. These owner's goals need to be meshed into the overall retro-Cx activities.

If we were to paint the picture of a perfect retro-CxA they would be a mosaic comprising of many parts:

• Architect to understand the physical space.
• MEP engineer to understand the HVAC&R, electrical components, etc. and how building codes at the time of the original construction compared to today have changed and impact the optimal use.
• Energy engineer to best understand how possible modifications will impact the energy consumption profiles of equipment, systems and the functional use of the building as currently been occupied. Construction superintendent to understand how and why the building is the way it is.
• Facilities, operations, and maintenance expert to have the insight to recognize various operational impacts that have created the current conditions. Controls expert to understand the hows and whys the control programming.
• Owner to have the perspective of how the building is and was being used to rebuild the outline of an OPR and BOD.
• Customer service oriented to have the people skills and polish to deal with the existing occupants while undertaking the job.
• 'Forensic investigator' to sleuth through and piece together what is the best retro-Cx approach (Plan) to achieve the most optimal operations – optimal may not be possible.

The goals and objectives of Cx are well defined in new construction. Although still an onerous task, the CxA's job in new construction is relatively straight forward compared to that in existing building retro-Cx. It will be difficult to find a single CxA individual will have all of the traits of a perfect retro-CxA. Therefore understanding the owner's objectives with retro-Cx and marrying it up the best retro-CxA team is essential to a successful outcome.

To further discuss this Article with Rob and other MEPBN Members visit the forum discussion page.

Rob de Grasse, P.E., PMP, LEED A.P., C.E.M. CxA
RD3 Sustainable Solutions
Rob is the founder and President of RD3, a facilities management consulting firm focusing of the optimization of facilities – commissioning solutions is one that this is delivered to RD3 clients.
www.RD3inc.com

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