A Review of Prior Research on Assessing Insertion Loss and Breakout Transmission Loss of Ductwork

Extensive research was performed on heating, ventilation, and air conditioning (HVAC) ductwork during the 1970's and 1980's. Much of this work was sponsored by the American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE). It seems that much of this work is now forgotten and the basis for the tables in the ASHRAE Handbook is not well understood. This paper reviews the past work supported by ASHRAE and to detail the limits of the ASHRAE Handbook. Previous finite element analysis and measurement studies are used to support the Handbook calculations when appropriate. Special consideration is given to the importance of structureborne flanking.