Experience

Experience has shown that very few (if any) HVAC systems
are free of all particulate. In fact, particle deposition on
component surfaces starts before the HVAC system is even
installed. Airborne particles in factory settings and assembly
areas are likely to settle on air-handling components and
fiber glass insulation, as well as adhere to the surface of
metal components.
The original installation process will subject the HVAC
system to even more contamination. Construction sites
contain a significant amount of airborne concrete dust,
gypsum dust, sand particles, biological particulate aerosols
and many other airborne contaminants in the ambient air.
These particles often settle on or within the HVAC system
during construction