Avoid Surprises with Existing Building Commissioning

WoodHarbinger-479-EditBy Jeff Yirak, P.E., LEED AP BD+C, O+M

This article is part of Wood Harbinger’s newsletter series.

Alexander Graham Bell got it right when he said, “Before anything else, preparation is the key to success.”

Whether new construction or remodels and tenant improvements, successful construction projects are planned, executed, monitored, and checked. When building a new building, the design and construction team has control of all the variables, streamlining this process. Air handling units and pumps are optimized in design and fine-tuned during balancing and commissioning. The electrical service has the right power sources in the right location for the installed equipment. When the job is completed, everything is working as it should. But what happens when the design and construction team isn’t in control of all of the variables, such as when working in an existing building with existing mechanical and electrical systems? Unforeseen conditions and preexisting problems may hamper the design, or worse, crop up during construction, resulting in last minute workarounds or extra effort to redesign. Existing Building Commissioning (EBCx) reveals important, up-front information about an existing building’s infrastructure, providing the design and construction team the insight they need to avoid problems during construction and commissioning.

What is Existing Building Commissioning?

EBCx is a holistic evaluation of the existing facility, including its current use requirements; current system equipment conditions, capacities, and controls; and the human element in its function, such as the maintenance and operation training of the facilities personnel. This is critical information to know prior to designing a remodel or tenant improvement in an existing space. Designers can’t rely on as-builts for information about current operating conditions; that knowledge can only come from a detailed evaluation of the facility. This is the kind of intelligence an EBCx program provides.

How Existing Building Commissioning Can Help

Let’s look at an example of a typical remodel/TI project: an Owner wants to convert the seventh floor of a warehouse building into office space. To get the conversation going with their consultants about how to accomplish this project, the Owner can:

  1. Forward as-built drawings of the facility and request a schematic design.
  2. Invite the consultants to do a walk-through of the facility prior to beginning design.
  3. Hire a seasoned commissioning authority with expertise in EBCx to provide an EBCx report for use by the consultant during design.

Option 1 is the quickest and easiest, but it provides the least amount of information to the consultant. As noted, as-builts don’t include any information about current operating conditions. This option assumes the as-builts accurately reflect the actual current conditions of the space, but this is often not the case. This can lead to unanticipated conflicts, such as utilities or ductwork present in the remodel space that weren’t shown on the as-builts, that weren’t addressed in the new design, which will result in necessary re-design during construction, construction delays, and costly change orders.

Option 2 at least allows the consultant an opportunity to conduct a cursory evaluation of the remodel space’s actual field conditions, but these walk-throughs are generally a very high-level overview of the space, and reveal almost nothing about system condition, operation, or capacity. The consultant typically isn’t permitted to thoroughly interrogate the controls system to establish the true baseline operating conditions. The resulting design then is based on assumptions of existing capacity and operating conditions. Potential problems during construction and commissioning include insufficient central utility capacity, such as plant heating or chilled water, to serve the new space, once again forcing last-minute re-design resulting in construction delays and change orders.

Option 3 is the surest bet to eliminating last-minute design changes; designers need a complete picture of the existing systems’ configuration and operation to avoid surprises during construction and commissioning. The EBCx master list of findings report will include a detailed analysis of the current facility infrastructure and operation, including potential findings such as mechanical and electrical code violations, failed equipment, physical or control system overrides, control sequence of operation failures, and more. Armed with this information, the Owner can choose to address whatever issues are revealed prior to the remodel project, or build it into the planned project scope at the outset, ensuring a comprehensive initial design, and a complete and functional system at turnover.

Other Existing Building Evaluation Methods

EBCx is the most rigorous and complete approach, but there are other methods and procedures used to evaluate existing buildings. An energy audit, such as an ASHRAE Level I or Level II audit, is one common method. But ASHRAE energy audits are just that–analyses of the building’s energy usage with recommendations to improve energy efficiency. They don’t—nor are they intended to—capture the full spectrum of the facility’s operation and maintenance parameters that affect the Owner. They don’t evaluate the functionality and purpose of existing systems, only how they’re performing from a utility-consumption perspective. This approach does provide useful data, but only a narrow piece of the puzzle.

It has been said there is a sixteen to one benefit ratio of issue prevention to resolution. An investment in the planning and development stage of a remodel or tenant improvement project to accurately establish existing system capabilities will pay big dividends during construction, commissioning, and turnover. Revealing the unknowns prior to starting design saves time and effort.

“Great discoveries and improvements invariably involve the cooperation of many minds…” – Alexander Graham Bell

By leveraging the combined expertise of an experienced existing building commissioning authority and an informed Owner and project team, the natural outcome is a successful project.

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