Making project intent clear and specific in writing the OPR and BOD pays off in numerous ways. The CxA is better able to accurately bid on the job, and better establish a clear commissioning plan. The more vague the project goals, the less effective commissioning presence will be.

Consider the potential cost implications and benefits of supplying an additional 30% of outdoor air. This may bring additional costs in the form of increased energy demand for conditioning greater air volumes and upsizing HVAC systems and fans. It is intended to bring more fresh air to occupants, potentially increasing their comfort and productivity.

ASHRAE 62.1 recognizes two procedures to demonstrate IAQ compliance: the IAQ Procedure methodology and the Ventilation Rate Procedure. The Ventilation Rate Procedure is easier to apply and is the prescribed path for this LEED prerequisite.

Projects with district energy systems must commission, for the prerequisite, all “downstream” equipment—systems installed for the building’s use and included in the project costs. Downstream equipment may include air handling units, variable-air-volume (VAV) boxes, duct work, pumps, controls and fans. “Upstream” district energy equipment, such as chillers, boilers, cogeneration equipment and other components of a district heating and cooling plant that serve the project building may need to be commissioned for the Enhanced Commissioning credit.

Review the Ventilation Rate Procedure methodology in ASHRAE 62.1-2007 Section 6.2 and the associated Table 6-1.

Develop the Basis of Design (BOD), working with the design team, including at least the architect, mechanical, electrical and plumbing engineers with lighting designer. Along with the OPR, the BOD facilitates constant discussion on realistic owner’s goals and the team’s input in addressing them. The architect, owner, and engineer update the OPR and BOD throughout the project to maintain accuracy for the CxA, and they are used as benchmarks during cost estimating and value engineering. The BOD also has a general role in project development, beyond its use in commissioning requirements.

Case 1 – Mechanical Ventilation

Analyze life-cycle cost tradeoffs between natural and mechanical ventilation systems. 

Consider the potential cost implications of natural ventilation. This may reduce or eliminate the need for fans and mechanical systems, but will require operable windows and a floor plan—probably a relatively open one—that is conducive to passive ventilation. 

The cost of fundamental commissioning services may vary from $0.35/ft2 to $0.75/ft2 depending on project type, variety of uses, complexity of systems and location of the project to name a few parameters. You may find it most helpful to get multiple proposal of fees and compare the scope to make sure everything required by LEED is covered without additional tasks.