Designing quiet, healthy ductwork

Acoustical duct liners promote a healthier interior environment by suppressing mechanical noise from heating, ventilating, and air conditioning (HVAC) systems. However the materials used to reduce or control noise may, themselves, have health implications. Fibrous acoustical insulation, for example, can release fibers into the air stream during installation or maintenance and when subjected to high velocity air or vibration. Recent studies have determined that glass fiber - the most prevalent duct liner material - should not be listed as a carcinogen. However, glass fiber is an acknowledged irritant. Moreover, long-term effects on sensitive populations - including children and individuals with compromised immune systems - have not been studied. Fibrous insulation can collect dust, thereby providing a site for mold and microbial growth. And dislodged particles can disturb sensitive electronics and clean room conditions. Some owners of facilities such as hospitals, schools, and laboratories have, therefore,...