INTRODUCTION TO HVAC COMMISSIONING
The primary goal of AVA AIRCON’S commissioning is to ensure a building’s HVAC systems are operating the way the owner intended.
Today, HVAC commissioning is more recognized as an important process needed for design, construction, operation, and maintenance of HVAC systems for commercial buildings. As commissioning becomes more popular – and in the near future, required – it’s that much more important to learn about the great benefits commissioning can provide an owner.
THREE TYPES OF COMMISSIONING
There are three main types of HVAC commissioning.
The first type, initial commissioning, occurs during the production of a new building or on a new HVAC system within an existing building. The second type, retro-commissioning, is the first-time commissioning has been implemented in an existing building on existing HVAC equipment. Finally, re-commissioning is commissioning HVAC systems that were already commissioned during the initial commissioning process, and the owner wants to verify, improve and document the performance of the existing HVAC systems down the road.
Once the proper type of commissioning has been determined for a particular building, the actual process of HVAC commissioning can begin.
THE COMMISSIONING PROCESS
The commissioning process begins with a thorough check of the HVAC equipment after it has been installed. The Commissioning agent checks the Installation of equipment and systems and verifies it along with its proper location. Then, we verify that installation meets construction details and manufacturer’s requirements. A custom checklist along with documentation of the equipment is created and submitted to the owner.
After verifying the correct equipment and material has been installed, witnessing equipment operation is the next step. It is necessary to verify and document proper operation which includes the startup, shut down, and sequence of operation. Noting any issues of improper sequence of operations or start and shut down issues must be reported to the necessary contractors immediately. After the equipment has been verified to operate properly, the HVAC equipment can be tested, adjusted, and balanced (TAB).
TAB (TEST, ADJUSTMENT AND BALANCE).
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.
Retro-Commissioning may not have design numbers. If this is the case, it is best to balance the unit on industry standards and comfort. 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.
Building pressure is important to comfort and equipment performance. Once the outside air and exhaust fans are balanced to within design the building pressure can be measured . Main entrance is where pressure is generally measured . Building pressure is generally slightly positive and measured in mm of water column. Building pressure can range and is included in the building balance schedule. 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 is submitted to the owner for approval.
WHY IS hVAC COMMISSIONING WORTH?
Many commissioning benefits, especially those that improve energy efficiency and occupant productivity, apply to both new and existing buildings. Benefits start early in the commissioning process and continue long after the space is occupied. From the beginning of the process, the team identifies potential problems and quickly corrects them. This reduces rework and the number of change orders during construction or retrofit.
The inclusion of O&M early on, and the ongoing documentation during the process, benefit O&M. The detailed process produces better manuals and training than that found in non-commissioned projects. Once the building has been turned over to the owner, O&M staff are better able to keep the systems running as close to original efficiency as possible.
Occupants enjoy a safer and more productive environment. The commissioning process as a result leads to systems that improve indoor environmental quality with better lighting, air quality, building pressure and temperature control.
And finally, organizations recognize commissioning as a risk management investment that also improves energy efficiency
KEY POINT BENEFITS
1. Proper performance ensures healthier and more productive occupants.
2. Developer can sell a well performing building faster with higher profit.
3. Products can deliver all benefits promised by manufacturer because of a commissioning agent.
HOW AVA AIRCON BENEFITS YOU AS A hVAC COMMISSIONING AGENT:
1. AVA AIRCON assures that all systems and components of the building is designed, installed, tested and operated and maintained according to the operation of developer, owner or end user.
2. We provide continuous monitoring operation over a life time and plan corrective action for both long term and short term.
3. We focus on training of operation and maintenance personnel so that misuse of the system can be avoided.
4. We are a customer-oriented company and are therefore not biased to any particular product/brand/affiliations and only decide what is best for our clients.
