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:
Local Law 85, better known as the NYC Energy Conservation Code, requires commissioning for buildings exceeding certain equipment capacities established in the code. These requirements affect new constructions and major modifications in existing buildings.
Local Law 87 requires retro-commissioning at 10-year intervals for all buildings under its coverage, along with energy audits.
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.
Improve your building performance with commissioning.
Commissioning Requirements in the NYC Energy Code
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:
HVAC and any associated systems: air distribution, exhaust and air quality monitoring.
Recovery systems: air, water and energy.
Controls on energy-consuming systems: manual or automatic, local or remote. Temperature-based controls and occupancy sensors are some examples.
Plumbing, including insulation, pumping and mixing.
Space heating and service water heating.
Renewable generation systems, as well as energy storage if present.
In general, any piece of equipment or component that is used for HVAC and which affects energy consumption.
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:
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.
Individual buildings with a gross area of at least 50,000 sq. ft.
Groups of 2 or more buildings under the same tax lot, if total area exceeds 100,00 sq. ft.
Groups of 2 or more buildings that are part of the same condominium, if total area exceeds 100,000 sq. ft.
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 certification was received within the last two years.
The building obtained one LEED point for Existing Building Commissioning.
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:
For supervision and certification, a Professional Engineer (PE), Registered Architect (RA), Certified Refrigerating System Operating Engineer, or Licensed High-Pressure Boiler Operating Engineer.
A team member with one of the following certifications:
Certified Commissioning Professional (CCP) - Building Commissioning Association (BCA)
Certified Building Commissioning Professional - Association of Energy Engineers (AEE)
Commissioning Process Management Professional (CPMP) - ASHRAE
Accredited Commissioning Process Authority Professional (ACPAP) - University of Wisconsin
A team member with at least one year of commissioning experience in buildings larger than 50,000 sq. ft.
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.