Commissioning

WHAT IS HVAC COMMISSIONING?

HVAC commissioning is regarded as an essential component of the entire construction process, which includes planning, building, monitoring, and maintaining an HVAC system. HVAC commissioning is typically used for two types of applications: commercial and residential. The commissioning process has been defined as a quality-focused process for improving project delivery. The process focuses on verifying and documenting that all commissioned systems and assemblies are planned, designed, installed, tested, operated, and maintained in accordance with the Owner’s Project Requirements.

As commissioning becomes increasingly popular – and, in the near future, mandated – it is even more vital to learn about the numerous benefits it may bring an owner. There are numerous definitions and interpretations of the commissioning process. In reality, the term commissioning cannot be found in a dictionary. The term commission refers to “a group of people who have been given the official job of finding information about something or controlling something” .

THREE MAJOR TYPES OF HVAC COMMISSIONING

Within the construction sector, there are generally three forms of commissioning that are extensively deployed and supplied, depending on the type of project/building: New construction commissioning (NCCx) Recommissioning/Ongoing Commissioning [OCx] Retro-commissioning (RCx).

Initial commissioning: This is performed on HVAC systems that are less than a year old or are being installed for the first time in new or existing buildings. This could also refer to post-construction commissioning.

Retro-Commissioning: This type of commissioning is performed on HVAC systems that are more than a year old and hadn’t been commissioned at the time the building was completed.

Re-commissioning: which is occurs when the building owner want to verify, improve, or document how the current system operates. As a result, re-commissioning applies to previously commissioned HVAC systems that require additional commissioning. It’s important to note that before any construction work begins, the type of HVAC commissioning must be determined according to how the building or infrastructure requires it.

SAFTEY

A well-maintained HVAC system is crucial for creating a safe and comfortable work environment for employees. This promotes productivity in the workplace while also preventing heat stress, which, if not addressed, can lead to heat illness.

EFFICIENCY

HVAC systems are typically among the most highly energy-intensive components of commercial buildings. If the installation fails, it can have a negative impact on the system’s overall performance and raise the consumption of energy even more.

TAB

Testing on HVAC equipment is essential for its performance and longevity. During initial commissioning, the mechanical plan sheet will include airflow requirements for each air device.
Retro-commissioning may not include design numbers. If this is the case, it is best to balance the unit’s industrial standards with comfort. To begin, record the initial conditions of the HVAC equipment. This comprises motor RPM, amperage, actual voltage, and airflow measurements through all supply, return, outside air, and exhaust devices. Check that the voltage and amperage match the motor’s specifications, and compare airflow readings to the design airflow. The air balancer regulates fan speed to maintain acceptable airflow (generally within ± 10%). The volume dampers then regulate the airflow of the air devices within the permissible range. 

Exhaust fan motor speeds are commonly adjusted during design to balance appliances such as kitchen and dishwasher hoods. The outside air is balanced for rooftop units equipped with economizers once the supply and return air have been adjusted to within design parameters. A spot check of each unit’s supply diffusers is required to confirm that the supply air did not drift out of range owing to outside air adjustments. Once the outside air has been adjusted to the design, the building pressure can be measured.

Building pressure is crucial for both comfort and equipment performance. The building pressure can only be measured when the outside air and exhaust fans have been balanced within the design. The pressure is normally measured near the main entrance to the building. Building pressure is often slightly positive and measured in inches of water column. Building pressure can vary and is factored into the building balancing schedule. Ensuring that the design building pressure meets requirements will reduce drafts and enhance infiltration. A final report including documentation of the equipment and material inspection, verification of start-up, shutdown, and operation, and the TAB report must be sent to the owner for approval.

BENEFITS

HVAC commissioning provides benefits on multiple levels. The building owner will have detailed record of the HVAC equipment’s operation and any faults that need to be addressed. The owner will be certain that the equipment is functioning properly, resulting in increased efficiency and comfort. The contractors will have record of all HVAC equipment’s functioning, which could result in fewer call-backs.