What is building commissioning?
Building commissioning is a systematic process of independent 3rd party testing for building systems. The purpose is to verify and document that they meet the owner's design intent.
Who is responsible for commissioning?
The most successful projects have a commissioning team made up of representatives from all disciplines of systems that are being commissioned. Although, the entire building can be commissioned including the roof, windows and air barriers, most often only the energy consuming systems not related to any industrial process are commissioned.
The commissioning team members include: the Owner, Architect, Design Engineers, Mechanical Contractor, Electrical Contractor, Balancing Contractor, Controls Contractor, Equipment Vendors, and a Commissioning Authority. The Commissioning Authority guides the team through the Commissioning process to assure the systems meet the Owners Project Requirements.
What are the benefits of commissioning?
According to studies of 100 of buildings, conducted by Lawrence Berkeley Laboratories, Building Commissioning provides the following benefits:
- Assures energy consuming systems are operating efficiently.
- Reduced operating and maintenance costs compared to non-commissioned buildings.
- Improves indoor air quality to eliminate the risk of sick building syndrome.
- Reduces warranty callbacks.
- Decreases occupant comfort complaints
- Increases occupant productivity
- Commissioning has a documented payback
- Reduces operations and maintenance expenses
- Reduces the carbon footprint of a facility and preserves the environment
- A benchmark’s to track future system performance
What stage of new project construction should commissioning start?
Owners who are a champion of commissioning know the value of incorporating the experience of the Commissioning Authority into the project in the earliest part of the design phase. The owner can benefit from the extensive hands on experience of the Commissioning Authority by establishing specific project requirements and system performance criteria that the designers can incorporated to help the building systems achieve the owners needs. Once the design phase has begun, the Commissioning Authority can participate in reviews at various design stages, this back check helps to assure the design team clearly understands the owner’s project requirements.
What does building commissioning cost?
The cost of building commissioning depends upon the complexity of the building systems and the scope of the services being requested. The smaller the building the higher the relative cost per sq. ft. because of economy of scale and duplication of tasks. Owners typically budget whole building commissioning at 0.5% of the overall construction cost. Some choose instead to budget commissioning costs at 1% to 3% of mechanical construction cost and .5% to 2.0% of electrical construction cost. Another rule of thumb in today's market is to budget from $.50 to $1.25 per square foot of space depending on the project systems complexity.
Costs can also vary significantly depending on the level of testing required and the system types. K12 schools, retail and speculative office buildings are the least expensive. Recreational Buildings, Museums, Libraries, College Classroom and Class A Office are mid-range. Laboratories, College Science Hospitals, Clean Rooms, and Data Centers require the most work and are on the higher end of the cost spectrum.
Testing should be performed using direct visual observation of the performance of equipment and systems by commissioning technicians. The contractors perform the test while the commissioning agents observe and record the results. Its recommended that central plant and major air handling equipment be functionally tested 100% of operational sequences. 10 to 20% Statistical testing is recommended for constant volume package rooftop equipment and terminal units like VAV boxes or heat pumps. The other 80% should still be tested by trend logs of performance is adequate to detect any issues. Larger buildings tend to have more terminal units and this reduces the cost.
The value of building commissioning far outweighs its financial cost. Lawrence Berkeley Laboratories have documented case studies on building commissioning projects showing that building commissioning generally pays for itself in from six months to four years through increased energy efficiency (reduced utility bills) and decreased operating costs (reduced maintenance and troubleshooting costs). There are numerous other benefits that are difficult to quantify. Commissioning will reduced the cost of change orders, increase occupant productivity by 1 to 2%, increase efficiency of construction labor and lessen warranty callbacks which is not included in the payback calculations. There are many instances the commissioning caught major issues that resulted in hundred of thousands of dollars of long term savings.
Title 24 and recent changes
Since 1978, Energy Efficiency Standards make buildings more comfortable, lower energy costs and reduce greenhouse gas emissions. Standards ensure that builders use the most energy efficient technologies and construction.
In addition, the 2016 Energy Standards have set out to simplify and clarify several areas that were new in the 2013 Energy Standards, which were identified during the public comment period as needing clarification. A few important clarifications were made to the commissioning requirements in Section 120.8 of the 2016 Energy Standards:
Commissioning is required for all new buildings with nonresidential conditioned space, including nonresidential spaces in hotel/motel and high-rise residential buildings.
The Owner’s Project Requirements (OPR) must include building envelope performance expectations under the 2016 Energy Standards.
Building Energy Efficiency Standards are designed to ensure new and existing buildings achieve energy efficiency and preserve outdoor and indoor environmental quality. These measures (Title 24, Part 6) are listed in the California Code of Regulations. Changes to the nonresidential requirements in the 2016 Building Energy Efficiency Standards (Energy Standards) largely follow ASHRAE 90.1 national standards and include energy conservation measures related to the building systems shown in(the attached document). The standards have been adopted, and once approved, will be implemented for projects permitted on or after January 1, 2017.