Today, heating, ventilation and airconditioning (HVAC) systems are becoming one of the key building blocks in modern infrastructure. These systems are found in almost all commercial as well as residential buildings. HVAC systems involve not only a major cost during construction but also contribute to a large operating cost as the building comes to life. HVAC systems account for a hopping 40-50 per cent of energy consumption of a commercial building. HVAC systems have also become complex, non-linear and dynamic. These systems are equipped with advanced controls and highly efficient components to aid in reducing a building’s energy efficiency, they require fine-tuning to operate at their highest level of efficiency while providing optimal climate conditions for occupants and contents of commercial spaces. Building Management Systems (BMS) are used to control and monitor complex HVAC systems as per design intent. They are used to collect data about the performance of the building, as well as energy consumption by individual
equipment and systems.
Building owners are challenged with getting financial returns from their investments while providing a building that is energy efficient. Many a times it is observed that HVAC systems and BMS do not work as per design. Chillers, AHUs, pumps, cooling tower, VRF systems do
not work as per design efficiencies. VFDs across fans and pumps do not modulate as per desired control logic. Facility team gets regular complaints from end-users for under- or over-cooling and poor indoor air quality. BMS fail to work as per control logic and systems run in manual mode. Owners do not get benefits expected from energy efficient and smart building and eventually no financial returns is achieved on their investments on these systems. Most of the time these issues occur due to improper commissioning and lack of
trained facility team to operate the systems.
Commissioning is arguably the most critical aspect of the sustainable development cycle as it ensures that a building is handed over to operate safely, efficiently and in accordance with how the owner intended. Commissioning has come to be recognised as the most important process needed for design, construction and operation and maintenance of HVAC
system to realise owners true project intent and establish energy saving and sustainable operation and management of the building system.
Proper commissioning is not just a testing and verification process and must start early in the project and continue until a comprehensive handover to the operations and maintenance team is achieved. Furthermore, one must look beyond simply commissioning individual systems as the complex buildings of today require very careful integration of numerous interdependent systems. This is essential to not only improving the efficiency of buildings and reducing maintenance costs but also overcoming safety issues in the building.
The commissioning process is defined as: “A quality-focused process for enhancing the delivery of a project. The process focuses upon verifying and documenting that all of the commissioned systems and assemblies are planned, designed, installed, tested, operated and maintained to meet the Owner’s Project Requirements”
Commissioning ensures building quality by using design review and on-site verification to help maximise energy efficiency, environmental health, and occupant comfort. The process improves indoor air quality by ensuring building components work correctly and that plans
are implemented efficiently and effectively. Commissioning also confirms that maintenance plans, O&M manuals, and training procedures are correct and in-place for maintenance staff to follow. It is also a mandatory requirement to hire commissioning authority for achieving Green Certification (USGBC/IGBC) for a project.
The key drivers are energy cost reduction, sustainability, reduced O&M costs, improved efficiency, and occupant health and safety, but these may vary according to building type and owner.
The commissioning process is complex owing to the interdependence of numerous systems and trades during a time critical point of the project. Commissioning management is a systematic process of managing the overall commissioning of a building from design to handover. Detailed planning and developing and continuously updating realistic commissioning programs are essential components of commissioning management but the success of the process in our view hinges on the expertise and experience of the commissioning management team.
Steps involved in commissioning processes are as follows:
Hire Commissioning Agent (CA): CxA should be part of the project from the earlydesign phases all the way through the end of the project. A commissioning authority or commissioning agent is usually contracted directly to a building owner as an independent representative to ensure unbiased performance of the CxA
Develop Owner’s Project Requirement: The OPR defines the expectations, goals, success criteria for the project. The CxA typically assists the owner in identifying
the facility’s requirements regarding such issues as energy efficiency, indoor environment, staff training, and O&M.
Develop Basis of Design: BOD documentation shows how a design meets the operational and performance requirements of a project and its systems. Together, this information tells the story for how the design team has translated the OPR into an actual design. It is an
important document as the project transitions into operations because it provides the design thinking and history so that the operations staff understands how the architect and engineers intended the systems to operate.
Develop Commissioning Plan: The commissioning team develops the Cx plan with input from the project team. The Cx plan begins with a program overview: – goals and objectives; general project information; systems to be commissioned. It describes the Cx team members, roles, and responsibilities communication protocol, coordination, meetings, and management. Finally, it summarises the Cx process activities. Reviewing the OPR; reviewing the BOD; developing systems functional test procedures; Verifying system
performance; reporting deficiencies and the resolution process and accepting the building systems.
Installation checks: During installation CxA should perform a visual inspection and document any issues or relevant observations. Inspect equipment for shipping damages. Verify equipment size, HP, voltage, and other criteria through spot measurements and verify all accessories are provided. Verify connected services do not place stresses on equipment. Verify equipment access and serviceability. Verify that the sensors are checked
individually to make sure they are reading properly and are in the correct locations, per the design documents.
Functional Testing: Each equipment is checked to verify that it can open, close, modulate, start, stop, energise in stages, etc. A system is run through each type of
operating mode including but not limited to start-up, shut down, capacity modulation, emergency and failure modes, alarm scenarios, occupied mode and unoccupied mode, and interlocks with other equipment. Results indicate whether the system passed, failed, or requires retesting.
Prepare Commissioning Report: The CxA should prepare the cx report after installation inspections and functional performance test verification. The report covers all components of the commissioning process, including:Executive summary of commissioning process and results, system deficiencies identified and resolution, and outstanding issues.
Training and O&M Manual: Proper training needs to be imparted to facility team to ensure intended operation of systems and equipment. Best way to ensure proper training is to involve facility team during final commissioning process. O&M manual must include: Sequences of operation for the building; building occupancy schedule; equipment run-time
schedules; setpoints for all HVAC equipment; lighting levels throughout the building; minimum outside air requirements; changes in schedules or setpoints for different seasons; systems narrative describing the systems and equipment; and preventive maintenance plan for building equipment described in the systems narrative and cx program.
Conclusion
Building Commissioning is not a new subject – it stems from the traditional activities of an architect and engineers throughout pre-design, design, construction and building start-up – but it has developed into a standalone professional specialisation that is now certifiable. The complexity and proliferation of technological building equipment and systems has led to the need for commissioning. A key driver for the growth of commissioning activities is sustainability, which focuses on occupant comfort and energy use reduction. Ensuring that the systems and equipment are installed and function properly will pay for itself many times over through the lower utility bills and increased occupant efficiency.
