What are the different types of building commissioning?

When you get a bunch of energy engineers in a room you’ll start hearing a lot of acronyms like Cx, RCx, and MBCx to name a few. It can be overwhelming to anyone not living and breathing building energy efficiency. So, let’s break down what they all mean in terms of optimizing your building’s energy use and operation.

Commissioning (Cx)

According to the California Commissioning Collaborative (CCC), the term commissioning originates from the ship building industry. Obviously, one wants a know a ship they’re about to set afloat is in fact seaworthy. To do this, it must be thoroughly examined and tested ensuring all systems are operational and all equipment functions as designed before setting it out to sea. When a ship completes such a thorough quality assurance process, it is called a commissioned ship. Someone decided to apply the same terminology to buildings.

When a building is commissioned it undergoes an intensive quality assurance process that begins during design and continues through construction, occupancy, and operations. Commissioning ensures that the new building operates as the owner intended and that building staff are prepared to operate and maintain its systems and equipment. – CCC

Commissioning is an extensive process applying to building new construction. It involves many different activities and is a very important process to ensure a building’s performance meets the design and owner’s expectations. You can see it outlined in this graphic from the CCC’s New Building’s Commissioning Guide below.

commissioning-process-flowchart-kw-engineering-energy-consultants

Source: California Commissioning Guide: New Buildings

If you start hearing the terms acceptance or functional testing when discussing commissioning and are curious, you can learn more about the difference between commissioning, acceptance testing and functional testing here.

Retro-commissioning (RCx)

There’s a similar process for existing buildings called, retro-commissioning (sometimes written without the hyphen as retrocommissioning, but it’s the same thing).

The commissioning process for existing buildings, commonly referred to as retrocommissioning, is a systematic process for improving an existing building’s performance by identifying and implementing relatively low-cost operational and maintenance improvements, helping to ensure that the building’s performance meets owner expectations. – CCC

The Retro-commissioning process involves investigating a building’s equipment and systems together to understand and improve their operation. If successful, it improves building performance by improving operations and maintenance procedures (O&M). Operational problems may have originated during design or construction or developed over the life of the building.

retrocommissioning-process-flowchart-kw-engineering-energy-consultants

Source: California Commissioning Guide: Existing Buildings

Re-commissioning

After retro-commissioning, we enter the world of re-commissioning which seeks to ensure energy savings and operational improvements last over time. In a perfect world, the Final Report from the RCx process includes a recommissioning plan. It is required every five years for State-owned buildings by the California Governor’s Executive Order S-20-04.

Buildings benefit from re-commissioning when there’s been changes in building use, changes in equipment maintenance schedules, or if operational problems occur more frequently.

Re-commissioning typically costs less than the RCx process since most of the timely data collection and analysis is already available from RCx activities, and just need to be revalidated.

California also requires large buildings receive a (USGBC) LEED®-EB rating.

What is LEED?

From the California Commissioning Guide: Existing Buildings:

LEED stands for Leadership in Energy and Environmental Design, a series of green building rating systems developed by the U.S. Green Building Council (USGBC).

LEED for new construction (LEED-NC) provides a standard for defining a “green building”. It is used by owners, architects, engineers, and contractors to take a holistic approach in evaluating a building and its systems over the life of the facility.

LEED for existing buildings (LEED-EB) is applicable to building operations, processes, system upgrades, and minor space changes, and can be used by buildings new to LEED certification, or as a recertification vehicle for buildings that have previously achieved a LEED rating. As with other LEED systems, existing buildings can achieve one of four ratings; Certified, Silver, Gold, and Platinum.

The LEED guidelines specify criteria in the following six categories. To be certified a project must meet all the prerequisites for each category:

  • Sustainable sites
  • Water efficiency
  • Energy and atmosphere
  • Materials and resources
  • Indoor environmental quality
  • Innovation

Ongoing commissioning

Continuous commissioning (CC) ® and monitoring-based commissioning (MBCx) are types of ongoing commissioning that use retro-commissioning techniques but unique in requiring ongoing monitoring. Both processes utilize extensive monitoring equipment to collect and analyze energy use and operations over time. Any changes from the energy use baseline can indicate opportunities for improvements or repairs.

The CCC differentiates between the two:

In Continuous Commissioning® (practiced by the Energy Systems Laboratory of Texas A&M University), third-party commissioning providers work closely with building staff to commission major pieces of equipment and involve the building staff in selecting and implementing improvements. The providers then commission the entire building, optimizing it to current operating requirements. Monitoring equipment is left in place, and a dedicated third-party analysis staff reviews data to ensure persistence of savings.

Monitoring-Based Commissioning (in a program provided by the University of California and California State University systems, along with California utilities) is similar in that it has an emphasis on involving the building staff and leaving monitoring equipment for ongoing diagnostics. It has an increased emphasis on training of the building staff, and empowering them to use the monitoring through analysis training, automation of diagnostics, and “smart” alarms.

Grocery Store MBCx

We’ve found MBCx extremely financially rewarding for grocery chains through our support of MBCx utility incentive programs as well as our private clients. With low cost projects, quick paybacks and ongoing operational improvements from fault detection and smart alarms, most customers see ROIs increase the razor thin profit margins typical of the grocery market sector.

Actual energy savings revealed by grocery MBCX (source: kW Engineering)

Commissioning pays off. What are you waiting for?

From sea to shining sea, our country benefits from the initial and ongoing quality assurance processes resulting from building commissioning. With better performing building stock, we reduce energy use, ultimately reducing greenhouse gas emissions. When considering commercial buildings account for almost 40% of US energy consumption, this can pay off huge dividends for the environment, as well as ROIs for building owners. If you’d like to talk shop about any of your commissioning needs, contact us anytime.

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