Manual D is a guide used in the HVAC (heating, ventilation, and air conditioning) industry to determine the design of duct systems in residential buildings. It is one of several manuals published by the Air Conditioning Contractors of America (ACCA) that provide industry standards for the design and installation of HVAC systems.
Manual J is another guide published by ACCA for the residential HVAC industry. It is used to determine the heating and cooling loads for a building, which helps in selecting the appropriate size and type of HVAC equipment.
Manual S is another guide published by ACCA for residential HVAC industry. It helps to select the appropriate type and size of HVAC equipment based on the heating and cooling loads calculated by Manual J and the design information provided in Manual D.