For the past 50 years, test and balance professionals have been the authorized experts who verify HVAC system efficiency. Let's take a look at the advancements this industry is pioneering and how it is moving into its rightful position as the preferred verification method across the HVAC industry.
Beyond Plan and Spec Balancing
For the last five decades, the balancing industry has focused on plan and spec balancing projects. The skills and diagnostic abilities developed by balancing professionals are pulling the us beyond “match the numbers balancing” into new segments of the HVAC industry.
Pre-design building surveys – For years, defects were thought to be solved by the designers specifying new replacement equipment. Unfortunately, installing new equipment on an existing, poorly performing duct system does not solve end user’s problems.
Better designers include field testing and diagnostics at the beginning of their projects. Balancers support the designer with solutions that provide greater comfort, far lower-tonnage equipment and significantly reduced energy costs. These solutions are then built into the HVAC system upgrade.
Diagnostics and troubleshooting – Customers suffering from long-standing HVAC issues are finding HVAC contractors, and other professionals -- with airside troubleshooting services -- to deliver relief from discomfort and high utility bills.
HVAC system commissioning and recommissioning –HVAC system commissioning is incomplete without balancing. Many contractors are proposing commissioning services centered on air balancing techniques directly to building owners.
Energy professionals – Most utility bills are driven by the cost of operating heating, cooling and ventilation system. Who you gonna call? Someone with test and balance services. If they don’t measure, they’re just guessing.
Facility management – Facility maintenance personnel are immersed in their HVAC systems and are charged with solving the problems occupants complain about. Adding information found in HVAC system balancing reports enhances their knowledge and assures a permanent solution.
Residential test and balance services – Homeowners are demanding more comfort and efficiency than ever before. Residential balancing provides the solutions they want. Stand-alone balancing departments are popping up everywhere. Furthermore, residential balancing is becoming required at an increasing rate for code compliance.
Assuring Manufacturer’s Specifications are Met
When equipment is designed, manufactured, and tested, its highest potential capacity and efficiency are promoted to the public. These tests are time proven and drive much of our industry’s direction. Specifications are then published detailing the maximum capacity in the equipment’s engineering specifications.
Balancing is the prescribed method to measure and adjust system performance. It assures that equipment published specifications are achieved once installed into a building.
How a Balancer Verifies HVAC System Performance
An air balancer’s job is to measure the system’s system operating performance and adjust it to optimize that performance. This includes inspections, testing, and calculations that quantify installed performance. A report is then published comparing the field collected data to manufacturer specifications and the requirements of the designer.
Measuring performance is the ultimate verification. The series of tests jump straight to the question “does the system work as it is intended?” This is answered by the balancing report.
The only way performance can be achieved is to measure its operation live in the field. If performance is there, all the requirements are successfully met, and the results are delivered. Results are verified by comparing each measurement and calculation to manufacturer and designer specifications
The holistic view of field measured performance is so superior to the splintered tests currently being used that there is little question performance verification by air balancing trumps every other method available today.
Air balancing tests include fan airflow, delivered airflow at the grilles, and a live duct leakage number. Total external static pressure and the pressure drop of each major system component is taken and compared to manufacturer and industry specifications.
Wet bulb and dry bulb temperatures are measured throughout the system. Then they are combined with airflow readings to determine the Btu capacity of the system. This can be accurately calculated and compared to design.
Live electrical measurements are taken, recorded, and compared to specifications. Fan horsepower and RPM are verified by voltage and amperage readings. It is amazing what can be verified when the system is measured under live operating conditions.
Pressures
Fan pressures, coil pressure drop, and filter pressure drop should all be compared to manufacturer’s specifications. Live pressure measurements of the duct system also check for adequate duct sizing and the effectiveness of the duct installation.
System defects can be identified by measuring various pressure drops. Fan law two can also be used to calculate how each pressure drop changes as airflow changes to match required airflow.
Airflow
Air balancing verifies that manufacturer-required airflow is delivered. It also provides evidence that equipment-generated Btu move from the equipment into the building. It also proves there are no duct system losses.
Air balance testing and verification services are leading the way into the future for balancing and HVAC contracting firms. For the past 50 years, these tests have been and will continue to be the foundation of HVAC system performance.
Rob “Doc” Falke serves the industry as president of National Comfort Institute -- an HVAC based training, certification, and membership organization. If you're an HVAC contractor or technician interested in air balance test procedures, contact Doc at [email protected]. Go to NCI’s website at nationalcomfortinstitute.com for free information, articles and downloads.