Commissioning starts by preventing errors in the most critical, early stages: planning and design. After the ground is broken, the process checks for correct installation and start-up. Only the next two stages, functional and performance testing, check for incorrect operation. The last two stages include training and first year occupancy services, and pave the way for a sustainable building.

Because commissioning is integrated into the entire construction process, it is termed integrated commissioning. This represents the state-of-the-art in building quality assurance. It is the combined process of setting realistic and well-defined goals for the modern functional workplace and confirming the goals have been met during design and construction. This closes the circle on quality and assures that actual building performance meets expectations (see Figure 1).

Figure 1. The eight stages of commissioning close the circle on building quality.

A Definition, Please?

Let's take a closer look at that definition.

Commissioning is planned. This means that commissioning is part of the project from the start and is integrated into programming, design, construction, training, and maintenance.

Commissioning is collaborative. It is a team process from the beginning. The commissioning professional causes quality to be built into the project by creating respect for quality within the team. To be sure, there is error identification, both in design and construction. But in the main, quality is built in, not added on.

Commissioning is systematic. Commissioning follows a strategy wherein all items are tested in all modes of operation. They are first inspected in a static condition to assure they are installed correctly. Equipment is then started up for the first time under controlled conditions. After start-up, systems are tested as a group to prove that they operate as planned

Commissioning is documented. The value of commissioning remains after the building is turned over to the operating staff. Key parameters of the systems tested are documented, organized and preserved in the commissioning report as well as the operations and maintenance (O&M) manuals.

To gain a better understanding of the commissioning process, let's divide the conception and birth of a new building into eight stages and look at how commissioning affects each stage.

The Eight Stages Of Commissioning

1. Predesign;

2. Design;

3. Bidding;

4. Early construction;

5. Acceptance - static inspection and start-up;

6. Acceptance - functional testing;

7. O&M staff training and documentation; and

8. Warranty period monitoring.

Usually, an independent individual or firm is contracted to see the commissioning process through these eight stages. This person or firm is called the commissioning authority (CA). The CA is an independent third party that is contracted directly to the owner. Alternatively, the CA may work for the design team, the general contractor, or the construction manager.

Contracting directly with the CA provides the best quality assurance for the owner. Many contractors have started their own in-house commissioning service because they have observed that the commissioning process reduces their callbacks by 25 percent to 95 percent. This benefits the owner as well as the contractor, but does not provide the same degree of protection as when the owner deals directly with an independent third party.

Many design firms are also providing commissioning services for their own projects and for projects designed by others. If the design firm commissions its own project, the rigor of the process can be questioned. Finding the right CA is no less important than hiring the right design team or contractor. Interview several potential candidates before the final selection is made. As a starting point in identifying qualified commissioning service providers, check with the Building Commissioning Association (BCA) (www.bcxa.org) and the annual National Conference on Building Commissioning (NCBC) (www.peci.org).

Quality Before Design?

The DI is the document recording how the building is expected to work, and is only as good as the work that goes into it. It is the CA's job to ask the right questions as the DI is being developed. The document is performance based and concentrates on what the occupants need and expect rather than on how the design team will provide it.

Designing The Quality Project

For example, the design intent might describe an assembly area that will house 100 people for two hours, be empty for an hour after that, provide comfort and operate at maximum energy efficiency. The basis of design would specify a variable air volume system controlled with occupancy sensors and a DDC control system. The actual design in the bid documents would specify components, air volumes, and the required control sequence. Commissioning assures that the equipment has been supplied and installed correctly, the air volumes and control sequence are correct, and that the overall system "works" at each occupancy level.

After confirming and documenting the design intent and basis of design, the CA continues to build in quality by checking the design documents for: