Modern construction is taking advanatage of the newest HVAC technologies and systems that are being designed with many more individually controlled temperature zones to improve occupant comfort. Variable speed fans and pumps are becoming more commonplace to provide the exact amount of heating and cooling system capacity in a manner that minimizes overall energy usage. New occupant air ventilation codes are much more restrictive and at the same time building envelopes are becoming much tighter. The combination of constantly changing HVAC airflow rates and increased demand for fresh- and filtered-ventilation air for all occupants is placing more emphasis on fine tuning HVAC system operation.
The purpose of testing, adjusting, and balancing (TAB) is to assure that an HVAC system is providing maximum occupant comfort at the lowest energy cost possible.
The following tips are included for initial planning.
Pre-planning for TAB work includes making certain that all the necessary parties and individuals to conduct the work are onboard. The type of building and systems to be tested and a realistic evaluation of what skills the TAB technician possesses are key planning elements.
Often, a controls specialist will be needed to operate the system for the TAB technician.
The representatives from the original equipment suppliers may be needed as a resource, at a minimum, but for complex equipment and systems or in a new building startup a manufacturer's representative may be required at the site to operate the mechanical equipment.
If the building has a facilities manager that individual is typically the most important participant with which the on-site TAB technicians will work. Facility managers have a substantial vested interest in ongoing customer satisfaction—the people who work or live in the building are actual end-use customers—and their satisfaction will ultimately be the key measure of success.
Occasionally, a system cannot be balanced or made to perform in accordance with the contract's design specifications regardless of the number of balancing dampers or valves that can be installed. Competent TAB technicians should be prepared for this possibility and work with the appropriate individuals to formulate recommendations as part of the final TAB report.
It should be made clear that the TAB work is not "commissioning." Most commissioning services are completed by firms having technicians experienced with each of the individual building systems—HVAC, lighting, plumbing, electrical, and security systems. ~ Whole Building Desing Guide, www.wbdg.org
Frequently Asked Question
What is Testing, Adjusting, and Balancing (TAB)?
System testing, adjusting, and balancing is the process of checking and adjusting all the environmental systems in a building to produce the design objectives. This process includes: balancing air and water distribution systems, adjusting the total system to provide design quantities, electrical measurement, establishing quantitate performance of all equipment, and verifying automatic controls.
Who is qualified to perform TAB?
Your local TAB firm should be certified by a national organization (like the NEBB) to ensure they adhere to accepted and approved standards. The firm should also be independent (meaning that they did not install the HVAC systems themselves) to ensure they provide an objective inspection and TAB report.
Is TAB necessary?
Yes, it ensures that your HVAC system is performing correctly and that you have a comfortable and energy-efficient building. It can mean the difference between comfortable and uncomfortable customers and employees, and between wasting and saving money. TAB can ensure that the owner / end-users are getting what you paid for.
Common signs my building is out of balance?
Common indicators are uncomfortable temperatures, hot / cold spots, sweating diffusers, exterior doors hard to open or close, drafts, smoke / smells from other areas, etc.
When should my building be tested and balanced?
The TAB can be performed at any time, but the best opportunity is near the end of construction (after all HVAC systems have been installed and start-up completed) but before turn-over to operations. During this time period, the TAB firm may uncover deficiencies that can still be corrected by the contractors before they leave the site and before the deficiencies create problems for building maintenance. SWTCx typically schedules a TAB just prior to a building’s opening.
How long does TAB take?
This largely depends on the size and complexity of your HVAC system. A typical small business may be 2 – 3 days. A large project such as a hotel, hospital, office building, or dormitory would take much longer.
What equipment or systems need to be balanced?
Because each HVAC system can greatly influence the performance of another, all systems within the building should be balanced, i.e. air distribution systems, exhaust systems, and hydronic systems.
What is the difference between an Air system balance and Hydronic system balance?
Air systems deal primarily with air movement. Hydronic systems deal primarily with water i.e. chill water, heating water.
When should existing buildings be rebalanced?
Buildings might need to be rebalanced more frequently if employee and customer complaints arise or if you are experiencing problems such as those discussed in the question above – (Common signs my building is out of balance?).
What makes SWTCx TAB unique?
SWTCx is the largest TAB firm in Oklahoma; we have earned a reputation for professionalism, integrity, and service excellence. We take a holistic approach toward HVAC problem-solving and do not limit our scope of work to simply taking data.
How does SWTCx offer a 'holistic approach' toward HVAC problem-solving?
SWTCx not only air balances your HVAC system, but we also commission it. We review the design, test the equipment, inspect the installation, and check the sequence of operation. Basically, we are there to make sure the owner gets the HVAC system specified for the project.
How much does the SWTCx TAB service cost?
Pricing varies depending on the job, its scope and systems. Please contact our Estimating team for more information.
What other TAB services does SWTB offer?
Sound and Vibration Testing, Complete HVAC Systems Survey, Duct Air Leakage Testing (DALT), Indoor Air Quality Testing (IAQ), HVAC Mechanical Systems Commissioning, and LEED certification.
Contact us to learn more.
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