Use TAB for optimal HVAC performance
Test and balance specialists ensure that a new HVAC system is meeting specifications.
Gerald T. Bauers, PE, President, National Environmental Balancing Bureau, Gaithersburg, Md. -- Consulting-Specifying Engineer, 4/11/2008 12:00:00 AM MT
A certified testing and balancing (TAB) firm, which is often behind the scenes and overlooked, can play a crucial role in delivering an energy-efficient HVAC system. An engineer’s best friend is an independent TAB agency that will test air and water systems, associated equipment and piping, and other HVAC components.
The MEP engineer designs the HVAC system and subsystems to perform at the designed intent. The TAB firm will review of the design documents for balanceability and construction observation. Balanceability involves a review and verification of all HVAC systems are fully balanced and documented. Construction observation is completed when a TAB firm ensures work on HVAC systems are completed based on the owner’s standards and quality described in the construction documents. The company will provide a methodical approach to TAB all systems to their optimal performance, and also will provide a critical function: verifiable test results.
The engineer needs to involve the TAB firm from the beginning of the project to ensure a well-designed building. The TAB firm begins the process in the design stage by reviewing the documents for balanceability and interfaces with the design team. During the construction stage, the TAB firm makes field observation reports, reviews submitted data, and prepares for the TAB phase. The process of TAB varies in length based on the number HVAC items, project specifications, and project conditions.
After the equipment start-up has been performed, and all systems are operational, the TAB firm can begin the TAB phase. The firm tests and balances each system and subsystem, including the control system, and documents the results of each test. If acceptable performance cannot be achieved because of system or construction deficiencies, the test data will be documented in writing to the appropriate responsible parties in order for the design engineer to take corrective action. Following the completion of TAB field services, a TAB report should be submitted to the engineer.
The final TAB report is a complete record of the HVAC system performance, including conditions of operation, items outstanding, and any deviations found during the TAB process. The final report also provides a reference of actual operating conditions for the owner and/or service personnel. During the occupancy stage, the engineer reviews, verifies, and accepts the TAB report.
In order to provide the most qualified results, TAB services should be performed by certified professionals. Certified TAB firms have proven technical expertise to perform these services, and demonstrated knowledge of HVAC systems and components. Certified firms have passed exams confirming their ability to identify and troubleshoot problems that could impact balanceability of the system. Costs for TAB services conducted by a certified firms, such as NEBB, are higher than an uncertified, unqualified firm. Costs for quality are always are more expensive.
On a national average, 90% of HVAC systems are reviewed by a TAB professional. In some cases, there are state requirements for having HVAC with certain tonnage to be reviewed by a certified firm. MEP Engineers should check their local building codes for specific requirements.
TAB firms can be an engineer’s best friend during the design, construction, and maintenance stages of a building. Understanding the crucial role of TAB services will assist in delivering a high-performing HVAC system.
TAB certification organizations:
Associated Air Balance Council
National Environmental Balancing Bureau
The Testing, Adjusting, and Balancing Bureau
-
This article doesn't mention an inherent limitation of the TAB process in that as a static...
David W. Bearg, PE, CIH - 2008-7-5 07:01:00
Bring TAB specs in line
06/13/2008NEBB conference sessions scheduled
08/13/2008HVAC System Rules of Thumb
07/29/2008
