HVAC Glass Fiber
The HVAC system is a common source of glass fiber in indoor office and school environments. These
glass fibers are generally coated with particles impacted onto their surfaces that mark them as having
been exposed to a moving air stream. These impacted particles typically have diameters smaller than
that of the fiber on which they rest. The color of the resin associated with glass fiber from the
HVAC system varies. It may be yellow, orange, red, green, gray, or black. The same "soundboard" may
have more than one color of resin on it. One common combination is a yellow resin used for the bulk
of the glass fiber mat with a coating of black, mineral-filled resin on the outer surface of the panel.
The resin used for the soundboard panels is generally heavily filled with clay or silica.