Testing, Adjusting, and Balancing of environmental systems is necessary to ensure that a building’s heating, ventilating, and air conditioning systems meet the design engineer’s objectives; especially the goals of comfort and economy. The American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE) define the three TAB operations this way: Test: To determine quantitative performance of equipment. (Measuring the air and water flow of the mechanical system) Adjust: To regulate the specified fluid flow rate and air patterns at the terminal equipment. (Adjust the total flows of the air and water to the mechanical system) Balance: To proportion flows within the distribution system according to specified design quantities.