What is HVAC testing & commissioning?
The primary goal of commissioning is to ensure a building’s HVAC systems are operating the way the owner intended. HVAC testing and commissioning requires throughout checkup of system after installation.This involves verifying of correct equipment materials and proper installation that meets construction details and manufacturers requirements.After verifying equipment and material, witnessing equipment operation is the next step. This includes startup, shutdown and sequence of operation which is documented.After the equipment has been verified to operate properly,it is ready to be tested/commissioned.
Today, HVAC commissioning is more recognized as an important process needed for design, construction, operation, and maintenance of HVAC systems for residential and commercial buildings.
Types Of HVAC Equipments
1)Air Handling Units (AHU)
2)Fan Coil Units (FCU)
3)Variable Air Volume
4)Exhaust Fans/ Ventilation Fans
c) Smoke Extract Fan
d) Staircase Pressurization Fan
6)Chilled Water Pumps
Why testing, adjusting and balancing (tab) of HVAC system is important?
Performing TAB on the HVAC equipment is crucial in the equipment’s performance and life.Initial commissioning will have airflow requirements for each air device on the mechanical plan sheet.
To begin, document the initial conditions of the HVAC equipment.This includes motor RPM, amperage, actual voltage,airflow measurements thru each supply, return, outside air, and exhaust device. Verify that the voltage and amperage are within the motor’s specifications, and compare airflow measurements with the design airflow.Typically, the air balancer adjusts the fan speed to bring the overall airflow within the allowed range (typically ± 10%) and then uses the volume dampers to adjust the airflow of the air devices within the allowed range.
Adjusting the fan motor speed of exhaust fans for items such as kitchen and dishwasher hoods is typical to balance the units during design.For rooftop units equipped with economizers, the outside air is balanced after the supply and return air have been adjusted to within design.Building pressure is important to comfort and equipment performance. The building pressure can only be measured once the outside air and exhaust fans are balanced to within design. Ensuring that the design building pressure is achieved will alleviate drafts and improve infiltration.A final report including documentation of the equipment and material inspection, verification of startup, shutdown, and operation, and the TAB report must be turned into the owner for approval.
The benefit of HVAC commissioning is realized on many levels:
- The contractors will have documentation of all the HVAC equipment’s performance which can lead to fewer call backs.
- The building owner will have complete documentation of how the HVAC equipment is operating and any issues that need to be resolved.
- The owner will know that the equipment is operating as intended and that efficiency and comfort will be attained.
- The owner will save energy, will save money, prolong equipment life and achieve lower building maintenance cost.
- The occupants will have a good indoor air quality, comfort, can maintain high levels of hygiene and can create healthy/odorless surroundings.
Re-balancing or validating of HVAC System every three to five years may achieve the good indoor air quality, comfort and efficiency at the peak performance of the system.