Energy and Atmosphere – (EA)
Written by Eve-Marie Olimpo
What is commissioning ? Commissioning or Cx is a term that comes up on most LEED project. The U.S. Green Building Council recognized the opportunity for reducing energy costs and greenhouse-gas emissions through this thorough process. It is important to understand what Cx mean, but mostly to understand how much it can impact a building performance. Building commissioning is basically a quality-focused process. It’s function is to improve the performance of building systems and equipment through planning, documenting, scheduling, testing, adjusting and verifying. Cx make sure that all the subsystems achieve the owner’s project requirements (OPR) as intended and as designed by the building architects and engineers. Cx should also include training for building staff to ensure they can operate and maintain its systems and equipment. The commissioning process is complex and it is usually performed by a Cx agent (CxA). The agent may be a subcontractor, an architect, a design engineer, test and balance contractor, or other trade contractor (HVAC/mechanical, electrical, fire protection, security, etc.). The CxA serves as a third party provider, independent of the design and construction teams, and provides the owner with an advocate that will serve the project through completion. The systems and subsystems that are usually commissioned are HVAC, plumbing, electrical, fire/life safety, building envelopes, interior systems, cogeneration, utility plants, sustainable systems, lighting, wastewater, controls, and building security system. Commissioning should be applicable throughout the lifecycle of a building to assure that the building is built and operates as designed. This process is needed not only during design and construction, but also when any renovation occurs as well as periodically during the on-going operation of a building. LEED EBOM address this in EA credit 2.1 Existing Building Commissioning-Investigation and Analysis, EA credit 2.2 Existing Building Commissioning-implementation, and EA credit 2.3 Existing Building Commissioning-Ongoing Commissioning. Retro-Commissioning Unfortunately a lot of construction projects are delivered to the owner without any thought for commissioning. Sometimes it’s because of a lack a time in the schedule or a lack of budget. Retro-commissioning is the application of the commissioning process to projects not previously commissioned. Many buildings delivered without undergoing the commissioning process have deficiencies in design or construction that do not allow the building to function properly or in an energy efficient manner. The goal of the retro-commissioning process is to identify the problems and proposed solutions to correct them. Retro-commissioning process provides a standardized method to gain the greatest efficiency gains and solve existing comfort and operational issues. Overall, retro-commissioning improves a building’s operations and maintenance (O&M) procedures and enhances the building performance while reducing its energy consumption. Often solutions recommended through the retro-commissioning process can be implemented at no- or low-cost and with little or no disruption to the building’s operations.Re-Commissioning Re-Commissioning is the application of the commissioning process applied to projects that have previously been commissioned. During building operations, systems may become out of balance. When building systems aren’t maintained and calibrated, they become inefficient and require more energy to run. Additionally, the needs of a facility may change as tenants, owners, and technologies change. The re-commissioning process allows a review of the owner project requirements and an update of the building set points that would represent the current use. A re-commissioning process is typically less expensive since documentation is available from the original commissioning of the building. Ideally, a plan for re-commissioning is established as part of a new building’s original commissioning process or an existing building’s retro-commissioning process. Ongoing Commissioning Continuous commissioning is the constant application of the commissioning process to a building that has been previously commissioned or retro-commissioned. The ongoing commissioning cycle usually last about 24 months. When the cycle is completed, the process get repeated. It ensures that a building does not deviate far from the current owner’s project requirements. Ongoing-commissioning use with a preventive maintenance plan are two great methods to keep energy costs low and minimize system problems caused by neglect and changes to building operations. Benefits of Commissioning Commercial buildings are complicated machines composed of lighting, cooling, heating, ventilation and control systems. Too often in a new building the operating staff doesn’t know how to operate it as it was designed to function. A lack of coordination, communication, and quality assurance during construction leaves many buildings with operating problems starting the day they open. Some of the problems include: indoor environmental quality complaints, missing or malfunctioning equipment, malfunctioning controls, unexpected equipment failures, and excessive energy costs. There are important financial benefits of commissioning. On average operating costs of a commissioned building range from 8 – 20% below that of a non-commissioned building. Cx will also increases energy efficiency long-term; enhances overall building quality, extends the life of existing equipment, reduces operating and maintenance (O&M) costs and provides preventive and predictive maintenance plans.