Recently, we completed an investigation which yielded
information I believe to be of possible value to the list membership.
While it is well known that CS solutions as weak as 5 ppm are of
value when impinged upon the surfaces of conventional air conditioning filters,
there was small data available as to how effective. We found that
approximately 3 ounces of 10 ppm CS sprayed over (both sides) of a 20" X 20"
X 1" AC intake filter.....once every 10 days, reduced the general viable
bacteria/virus populations (expressing on the filter surfaces) to 5%--or
less--of those found on the control filters. In some cases, where 20 ppm was
used, and the interval for filter cleaning shortened to 7 days----the efficacy
improved to better than 98%. It is of interest to note that some filters were
mechanically/pneumatically cleaned by simply knocking them against a screened
surface and exposing to 60+ psi cleaning via air hose nozzles 4
times....before being replaced with new ones-----without substantial
degradation in overall system performance.
Of note was, free-air samples from areas serviced by a $1000.00
air-scrubber, contained MORE live pathogens.....than did the CS test areas
utilizing the foregoing arrangement of CS impregnated intake filters.
One word of caution.....because of the large, initial, wetted
surface of the intake filter it would be prudent to check the filter for
heavier-than-usual accumulations of dirt/dust particulates at about 5 days.
after the initial installation.. This is of special importance in areas
exhibiting high dust concentrations. It may be of import for members to know
that approximately 80% of all A/C system failures have their primary cause as
"restricted air flow"......mainly from occluded intake filters (this includes,
but is not limited to: frozen evaporator surfaces, compressor failure due to
excessive work-load, continuously high discharge pressures,etc.)
I hope this information is of value to some.
Sincerely, Brooks Bradley.
