Commissioning (Cx) is a process used to verify that facilities and systems are operating properly. Re-Commissioning (Rx-Cx) occurs when a building that has already been commissioned is commissioned either as part of a regular, periodic building performance review, or when triggered by a building use or system change.

Retro-Cx consists of testing and adjusting building systems to optimize safety and security, occupant comfort, and energy use and savings.

Cx offers facilities staff a direct, tangible means of supporting business objectives and provides a benchmark by which to measure a building’s operational performance improvement.

The economic benefit of Cx includes:

• System optimization and enhanced performance
• Increased energy efficiency
• Identification of operations, controls, and maintenance problems, including reduced premature equipment failure
• Productivity and health benefits from improved indoor environmental quality (IEQ)

Cx also aids in long-term planning and budgeting by identifying targets for future capital improvement projects. Re-Cx typically occurs after systems have been in operation for at least one year. Best practice recommends re-Cx every five years at a minimum.

Cx is a team effort that frequently involves both internal staff and external contractors. Site facilities staff can often establish the process and perform many of the required tests. Team leads are typically third-party Cx agents, but may also be qualified members of the site’s facilities staff, mechanical contractors, or design engineers.

A Cx agent reviews the settings on a rooftop mechanical unit

Image Source: Paladino and Company

The Cx team’s scope of work should include the development of a plan that:

• Identifies Cx goals and objectives, such as reducing energy cost, reducing maintenance time and cost, improving indoor air quality (IAQ), and improving thermal comfort;
• Defines which building systems are to be commissioned—the Cx plan should focus on systems that represent a large proportion of a facility’s energy use: systems with consistent operational problems, systems where failure presents a high risk to productivity, safety or security, and systems that are responsible for the most occupant complaints;

• Determines how selected equipment and systems are intended to operate or how they could operate more efficiently given current building conditions;
• Defines performance criteria, functional performance test procedures, or verification checklists for each system or piece of equipment. (Resources: Design and Commissioning Report (energy.gov) ).

Table 2: Should this building be commissioned?

Data Source: Adapted from U.S. Department of Energy