Retrocommissioning: Essential Questions
In recent years, managers in institutional and commercial facilities have paid greater attention to commissioning and retrocommissioning for building systems. Maintenance and engineering managers are looking to improve energy efficiency, enhance the quality of construction, and ensure the built facility meets the intent of the original design. Commissioning can help managers achieve these goals.
The process is especially important to managers, in part, because it provides the tools to manage facilities better. It defines building-system performance criteria, a baseline for building performance, and a means of tracking and evaluating building performance over time.
What is its Role?
A manager’s primary goal is ensuring the operation and maintenance of physical plants to support an organization’s overall objectives. A manager’s ability to provide this support depends on understanding these objectives, understanding the ways systems relate to the objectives, and having appropriate and accurate system information readily available.
Both commissioning and retrocommissioning offer managers a direct, tangible means of supporting business objectives, and they provide a benchmark by which to measure a building’s operational performance.
The processes also provide real information that correlates building-system performance with real monetary savings, whether through proven energy use reduction, improved maintenance, or increased productivity. Commissioning unites facilities operations with business operations.
As defined by ASHRAE, commissioning is a “quality-oriented process for achieving, verifying and documenting that the performance of facilities, systems and assemblies meets defined objectives and criteria.” Typically, the process occurs during design and construction.
Retrocommissioning is a similar process in its goal of verifying that systems perform as closely as possible to defined performance criteria. But it typically occurs after systems have been in operation for some time.
In general, the overall goal of both processes is to verify and document that the systems have been installed properly and that they perform according to the owner’s operational needs.
For new-construction projects, a commissioning agent typically performs the tasks, with assistance from the construction team. For existing systems not associated with a new-design or -construction project, however, a maintenance and engineering manager might oversee the process. In fact, the facilities staff might perform most ongoing commissioning work.
This decision is up to the manager and depends on the performance requirements defined for the systems, the system resources already in place, and the skill level and availability of the in-house facilities staff.
The answer to this question for any manager revolves around three issues: safety and security, people’s comfort, and energy use and savings. A variety of issues can trigger the desire for retrocommissioning, but they usually fall under one of these core issues.
The decision to retrocommission might arise from a failure to maintain space temperature or humidity requirements, from an unexplained dramatic increase in energy use, or from upcoming modifications to systems requiring performance data that does not exist.
Retrocommissioning provides many benefits, including:
- documenting accurately the existing system’s function and performance
- verifying that system performance meets the facility’s requirements
- benchmarking the performance of existing systems for future changes
- identifying problems in the system
- generating energy savings by identifying system problems, such as missing insulation, non-functioning controls valves, or leaky ductwork.
Most organizations do not commission building systems. In fact, original as-built drawings often provide the only documentation of design intent. The only verification that systems ever met the operational parameters might be the original HVAC test-and-balance report.
Over the span of a few years, it is highly likely that in-house engineering staff modified building systems. While modifying the systems is not a problem in itself, the resulting lack of documentation can be. Problems can become apparent when an organization changes the use of a space, a new documented modification must be made, or a system somehow fails.
For example, a highly mechanized facility recently was undergoing layout modifications. But before proceeding with the work, managers needed to verify a key system’s capacity to ensure the existing system could meet the proposed increase in system load.
While researching background information, it became apparent that the design intent and operational criteria were not available. This situation was surprising, given the facility’s critical nature. It also was surprising because the system had been in place for several years and had often been modified by the facilities staff and construction teams. Technicians also had tested parts of the system, but they had never documented overall system capacity.
Because no data was available on the total system’s actual performance, it was impossible to verify additional capacity that might be available without testing the system. This situation could have been avoided had the required and actual data system performance been available.
What is the Scope?
As with any process, the most critical step in commissioning and retrocommissioning is defining objectives and requirements. A manager can make the process complex or simple, highly detailed or straightforward, but the key questions in developing commissioning criteria are these:
- How much detail is required? The level of detail of information needed for an office building is quite different from that required for a research laboratory.
- How much data is required? More information isn’t necessarily better. Sometimes, it’s just more.
- How much data does a manager want? Ideally, commissioning is an ongoing process that carries through a facility’s life. As a result, managers must decide on the amount of data necessary to demonstrate conformance with performance criteria. This level of data forms the template for future updates and modifications.
Which Systems Need Commissioning?
At a minimum, managers should schedule commissioning for systems related to life safety and health safety. These systems often require testing, either by code or by local authorities.
Examples of life-safety systems to commission include those for fire suppression and fire alarms. Health safety systems to commission include fume hoods, bio-safety cabinets, associated exhaust fans, and ductwork.
Managers also should schedule commissioning and regular testing for systems critical to a facility’s mission. Critical systems include those that, if they fail, are immediately detrimental to the bottom line. These can include HVAC systems, power systems, and process-gas systems.
The type of system information collected during commissioning depends on the identified objectives. For more information on specific systems and data to collect, see the article on this page.
How Can we Ensure Results?
Through observation and testing, commissioning should uncover problems in systems. But how can managers turn the results of a commissioning report into action? And how can managers ensure the process is maintained?
First, the facilities team must buy into the plan and process for it to succeed. Second, departments must provide and maintain documentation. Experience indicates that the simplest approach to providing documentation often is the most likely to succeed:
- Keep the commissioning scope focused on issues important to the business mission.
- Distill the system requirements to the essentials.
- Collect only important and especially useful information.
One straightforward method of documentation is a checklist, such as the sample of a partial commissioning checklist on below. Inspectors can use such a document during initial commissioning work to ensure they review, test and verify items of concern.
Managers can easily convert it into a list of action items to address, confirm and file as a primary document that is available for future reference. Managers also can use this checklist for ongoing commissioning to ensure consistent data collection.
Commissioning unites facility operations with business objectives.
From an operational perspective, it documents system-performance criteria, provides a performance benchmark, and provides data for tracking, evaluating, and improving systems.
From the business perspective, commissioning and retrocommissioning give managers real information that correlates system performance to real monetary savings through cuts in energy use, improved maintenance and increased productivity.
Laurie Gilmer is a professional engineer with Facility Engineering Associates (FEA) — www.feapc.com — a nationwide consulting firm that focuses on extending the life of and improving existing facilities.
Matching Data and Objectives
The type of data managers need to have collected during commissioning or retrocommissioning must match objectives identified before the process begins. The following list is a sample of key systems and types of data that technicians can collect, measure, and monitor as part of a commissioning or retrocommissioning process:
— Laurie A. Gilmer, P.E.