The "HygenAir™ A+H Hygienic Air Handler Engineering Manual" provides a comprehensive guide to various aspects of hygienic air handling for industrial refrigeration systems. The manual covers topics such as refrigeration systems, cooling coil construction, corrosion resistance, psychrometrics, heat transfer calculations, room load calculations, dealing with particulate contaminants, supply air flowrate considerations, humidity control strategies, operating modes, part load operation, filtration methods, pathogen control strategies, and U.S. food production facility regulations. This manual serves as a valuable resource for engineers and professionals involved in the design, operation, and maintenance of air handling systems in food processing systems, with an emphasis on hygiene and air quality.