Recommissioning (RCx) Guide for Building Owners and Managers

Chapter 1 - Building Performance as a Business Strategy

A Case for Improving Building Performance

No matter how well building operators and service contractors maintain equipment, if it operates inefficiently or more often than needed, energy waste and reliability problems can occur. Also, over time, building uses change – occupants move, spaces are reconfigured, new equipment is added – possibly rendering previous systems and settings ineffective.  

Today's buildings are complex, employing highly inter-dependent systems with sophisticated controls; therefore, even small operational problems can have big impacts on performance. Even if building staff have been able to work out most of the operational "bugs", they are often forced to solve daily problems under severe time constraints and without the benefit of appropriate or complete documentation or training on system-integration issues.

Achieving optimum building performance requires an approach that helps to ensure that equipment and systems perform together effectively and efficiently to meet the building owner's operating requirements and expectations. When this process occurs during the construction of the building, it is referred to as "commissioning". Applying a similar process to existing buildings and their operations is referred to as "retro commissioning" or "recommissioning" as shown in following Table 1.

Table 1: Improving building performance approaches

Commissioning Terminology

Commissioning (Cx) is an intensive quality assurance process that begins during the design of a new building and continues through construction, occupancy, and operation. Cx ensures that the new building operates as the owner initially intended and that building staff are prepared to operate and maintain its systems and equipment. 

Retrocommissioning is a commissioning process that applies to existing buildings that were not commissioned originally. It seeks to improve how building equipment and systems function together. It often resolves problems that occurred during building design or construction, or addresses problems that have developed during the building’s life. The ReCx inspection, diagnostic and repair process ensures building equipment and systems are operating optimally to meet current occupant needs.

Recommissioning (RCx) is a re-optimization process for existing buildings that have already been either commissioned or retrocommissioned. It ensures building equipment and systems are operating optimally to meet current occupant needs. It provides a rigorous investigation approach to identify problems and integration issues. The RCx primary focus is on identifying "low cost/no cost" operational improvements given the building’s current usage to obtain comfort and energy savings. It may be done alone or in concert with a retrofit project. 

Important notice: For the purposes of this Guide, the term "recommissioning" (RCx) has been chosen as the generic term for commissioning existing buildings.⁶ Retro-commissioning, while similar, is defined as a one-time service to existing buildings that have not been commissioned initially.

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⁶ For the purposes of this RCx Guide, NRCan uses terminology commonly understood in the Canadian market that is slightly different from the US-EPA Guide