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HVAC BALANCE Stairwell Testing - Call us at (800) 217-8437There is a misconception that variable air volume systems are self-balancing. Our air balance services correct this problem. We check to ensure that registers and grilles are installed. We test and adjust each VAV box, diffuser, grille, and register to within +/- 10% of design requirements. A multi-zone unit uses a single fan to produce both cold and hot air. Cooling and heating coils are both used to produce either cold air, hot air, or a mixture of both when the space temperature has been satisfied. Actuators are used to move mixing dampers in the discharge of the unit to achieve the correct position to meet space temperature requirements. The unit can maintain a designed discharge air temperature on both the cooling and heating sides of the unit by modulating the chilled and hot water valves. The unit is made up of 2 or more zones serving various spaces. Each zone duct will have a manual balancing damper that MUST be installed to balance out the airflow on each zone duct. Design airflow should be set first by pitot tube traverse through the zones before any grille balancing is started. Water Balance Performance Verification involves the following steps: (1) Verify that all control settings have been returned to normal set points, (2) Verify that all discrepancies and punch list items have been corrected, (3) Allow the system to operate automatically for 24 hours, (4) Identify all rooms on temperature test sheets, (5) Note room numbers where all thermostats are located. Record set points of all thermostats, (6) Record temperatures in all rooms. Record outside air temperatures and weather conditions at the beginning and end of temperature tests, and (7) Recheck operation of all HVAC equipment in any room that is not maintaining temperature set point and correct, if necessary. Energy auditors have developed several methods for testing duct tightness. These methods vary from fast and dirty to time-consuming and accurate. Builders interested in tight duct systems should familiarize themselves with the range of available duct testing options: (1) Using only a blower door, (2) Using a blower door and a pressure pan, (3) Using a Duct Blaster, (4) Using a Duct Blaster and a blower door; and (5) Using a theatrical fog machine. Although the initial cost of installing a VAV system is a somewhat higher than a traditional constant air volume (CAV) system; due in part to special controllers used to control the fan speeds and the added complexity of the VAV terminal boxes, the money saved when these big fans are running below maximum speed quickly pays off. Mechanical ventilation is the use of mechanical air handling systems commonly referred to as heating, ventilation, and air conditioning (HVAC) systems to ventilate buildings. Most commercial buildings use mechanical ventilation, which is more controllable and responsive than natural ventilation in providing adequate indoor air quality. However, mechanical ventilation also can exacerbate infiltration and ex filtration, which can compromise indoor air quality. Research clearly shows that when a fire occurs in a multi-compartmented building, the smoke from the fire is a far greater hazard to the occupants than the fire itself. Smoke can kill by asphyxiation or poisoning well before the temperature of the fire or smoke causes injury. Smoke also obscures vision, preventing occupants from finding safe escape routes and hindering the fire brigade search and rescue operation. The term HVAC refers to the three disciplines of Heating, Ventilating, and Air-Conditioning. A fourth discipline, Controls, pervades the entire HVAC field. Controls determine how HVAC systems operate to meet the design goals of comfort, safety, and cost-effective operation. |
