The process of commissioning air doors is not much different than that for any other piece of HVAC equipment. The most important step is to define the commissioning responsibilities of the various contractors. The mechanical and electrical contractors responsibilities must be set out in the contract specifications defining their work.
As the commissioning process applies to air doors, the scope of commissioning includes the installation inspections, flow adjustments and calibrations, coordination with building controls, and air balancing.
There are several different variations on who has the overall responsibility for the commissioning process. One option would be to have the installing contractor in charge of the commissioning of their work. A second option would be to have the engineer of record in charge of the commissioning. A third way is to have a commissioning agency (CA) in charge of the overall commissioning process.
A typical commissioning checklist is as follows (when using a CA):
Contractor to provide requirements to CA for submittal data, O&M data, and training information.
Contractor to notify CA a minimum of two weeks in advance of equipment start-ups, so that the CA may witness equipment startup.
Prior to start-up, contractor to inspect, check, and confirm the correct installation of equipment.
At start-up, contractor to perform function test on equipment to ensure equipment is fully functional and ready for the CA to witness.
CA witnesses and verifies operation of equipment and completes inspection report for owner.
The selection of the commissioning leader is driven by the extent and scope of the project. For small projects, such as installing air doors, the contractor or engineer of record can perform the commissioning. The contractor can easily perform the installation work and commissioning work without conflict. For large projects, such as entire buildings, a commissioning agency is the better choice. This commissioning agency's sole function is to provide the owner with an unbiased evaluation of the equipment.
The majority of the problems detected during commissioning are associated with air doors that are improperly mounted. The air door creates an air barrier and proper mounting is critical to achieve this barrier. Improper installation ranges from not installing the unit close enough to the opening to improper mounting heights.
Air doors are mounted above doorways where people frequently pass through. The air doors must be designed into the building so that there is adequate support for the piece of equipment. For example, an 8-ft air door weighs approximately 200 lb. Properly designing for the equipment weight will prevent the unit from falling.
Air doors will vibrate during operation. Commissioning the installation will verify that the proper locking nuts have been installed, thus, preventing the unit from vibrating free from the mounting hardware.
Air doors can be operated so that the door will be controlled by a building controller or by a motion sensor. With the building controller, the air door will be operated based on a predefined program. Starting and stopping air doors will likely be controlled by a time schedule.
The operation of the air door must take into account the anticipated number of times the door opening will be passed through in a given day. In a retail facility, such as a grocery store or gas station/convenience mart, one would expect a high amount of throughput traffic.
If the air doors are controlled by a motion sensor, the doors would be cycling on and off throughout the day and resulting in wear on the equipment. However, if the air door is left running continuously throughout the day, the number of on/off cycles will be greatly reduced.
For previous Equipment Notebook articles, visit www.hpac.com.
Brad Morris, PE, is the manager of M/E/P/R engineering for AETOS Construction, a division of the Giant Eagle Corp. in Pittsburgh. He has 11 years of experience in the chemical and mechanical engineering fields. He can be reached at [email protected].