Commissioning can be described as a quality assurance process, where the goal is to ensure a project is designed, installed and configured according to the requirements of the owner. In the construction industry, when the term commissioning is used by itself, it normally refers to a new building. The term retro-commissioning applies for existing buildings that have not been commissioned before or in a long time, and the term recommissioning applies when the process is already being carried out periodically. As a result, retro-commissioning tends to be a more a labor-intensive process than recommissioning.
Commissioning normally has an excellent return on investment. The process focuses on optimizing existing installations, while performing minor reparations or part replacements where necessary, but most of the commissioning cost is composed of professional services and skilled labor. In many cases, a payback period of less than one year is possible.
Given its benefits, commissioning is highly recommended for all buildings on a regular basis. However, there are two main cases where it is mandated by New York City laws:
Both laws are part of the Greener, Greater Buildings Program (GGBP), and ambitious initiative by the NYC government to reduce the environmental footprint of the largest buildings in the city. Commissioning is strongly recommended even when not required by laws or building codes, but being aware of the deadlines and requirements is important to avoid penalties.
The NYC Energy Code dedicates section C408 to commissioning requirements, covering three categories of building systems: mechanical installations, service water heating and electrical power. The code provides a minimum list of equipment and components that must be covered:
In all cases, the project owner must get a commissioning plan developed by a qualified agency, according to a list of items and requirements provided in the NYC Energy Code. Some of the main requirements are a description of the activities required, a detailed list of equipment with the corresponding testing procedures, conditions for performing the tests, and key performance metrics that will be analyzed. The code also requires an operating and maintenance manual for building systems.
There are two main exceptions where commissioning is not mandated by NYC Energy Code, described in the following table:
EXCEPTIONS |
CONDITIONS FOR THE EXCEPTION TO APPLY |
1)Mechanical systems and service hot water |
-Cooling capacity below 480,000 BTU/hour -Heating capacity below 600,000 BTU/hour, considering both space heating and hot water |
2)Renewable energy systems |
Generating capacity below 25 kW. |
The NYC Energy Code requires system adjusting and balancing as part of the commissioning scope. The procedure must be carried out according to ASHRAE 111, or an equivalent standard approved by the NYC Dept. of Buildings. Specific requirements are provided for air systems and hydronic systems.
A preliminary commissioning report is acceptable for building approval, as long as it meets the conditions provided in the NYC Energy Code. The deadline for the final report is 30 months after project completion for buildings having at least 500,000 sq.ft., and 18 months for all other buildings. If the occupancy group is R-2, the deadline is 18 months regardless of floor area.
Local Law 87 focuses on energy audits and retro-commissioning, making them mandatory for all buildings in NYC that meet any of the following conditions:
If a building is covered by Local Law 87, the owner must perform an energy audit and retro-commissioning at 10 year intervals, and submit a report. The interval is determined by the last digit in the tax ID; for example, if the tax ID for a property ends in “9” the next two reports are due on 2019 and 2029.
LEED-certified buildings are exempt from retro-commissioning under LL87 if they meet the two following conditions:
The retro-commissioning process involves an inspection of operating protocols, considering calibration and sequencing. LL87 also requires component cleaning and reparation, verifying that all documentation is up-to-date and in order, and making sure the operation and maintenance staff is trained properly.
To be acceptable under LL87, the retro-commissioning process must be carried out by a team of professionals having the following qualifications:
Regular commissioning is recommended for all property owners, given the potential savings. However, it is strongly recommended if a project has been experiencing a drop in performance over recent years with no apparent reason. Also keep in mind that commissioning is mandatory under some NYC laws - you can get a professional opinion to determine if your building is subject to mandatory commissioning under the NYC Energy Code or under Local Law 87.
NYC buildings are subject to local laws that cover areas like emissions and fire safety. NY Engineers can help you stay compliant: call (786) 788-0295212-575-5300 or write at info@ny-engineers.com.