Environmental Engineering Reference
In-Depth Information
Biocides are used in building environments as disinfectants in cleaning
agents for sinks, counters, bathtubs, showers, toilet bowls, baby nurseries,
diaper pails, and some soap products. They are also used in products such
as furnace and air handling system filters, carpeting, and paints. They are
used to control the growth of microbial slimes on exterior elements of cooling
coil condensate drip pans and in sumps of cooling towers.
Antimicrobial compounds commonly used in residential applications
include sodium/calcium hypochlorite, ethanol, isopropyl alcohol, pine oil,
o
-phenylphenol, 2-benzyl-4-chlorophenol (BCP), glycolic acid, and phospho-
ric acid. Quaternary ammonium compounds are used for more heavy-duty
applications in hospitals, large buildings, etc.
Ortho
-phenylphenol has been
the principal ingredient in a widely advertised commercial product used in
nurseries and in the disinfectant treatment of toilet bowls in residences,
schools, and hotel/motel rooms. It has a characteristic strong chemical odor.
Its use has been declining in recent years.
A variety of compounds are used as biocides in carpeting products.
These include such apparently nonvolatile compounds as zincomedine (zinc
complex of pyrethione) and organosilane compounds such as octadecy-
lamino-trimethylsilylpropyl ammonium chloride. Biocides have been histor-
ically used in carpet manufacture to reduce potential microbial growth asso-
ciated with accidental wetting and wetting associated with shampooing.
Shampoos themselves may contain biocides.
Biocides are used in paint formulations to prevent microbial degradation
of the product or to protect substrate materials coated with paints (mold-
inhibiting paints are widely available).
Mercury biocides have been used extensively to control the growth of
mold and bacteria during production and storage of interior, water-based,
latex paints and to control mold growth in exterior latex paints on a long-
term basis. Use of mercury biocides in latex paint was approved by USEPA
despite their known adverse human health effects. Approximately 25 to 30%
of interior latex paints manufactured in the U.S. contained organic mercury
compounds before their use was discontinued in a voluntary agreement
between manufacturers and USEPA in 1990.
Substances used in biocidal treatment of furnace/air handling unit filters
include a commercial product called Intercept; cooling tower water is treated
with quaternary ammonium compounds, bis (tri-
n
-butyl tin) oxide, and
chlorine/hypochlorite.
Duct cleaning has been widely promoted by service providers in North
America to improve IAQ. After cleaning, ducts are commonly treated with
one or more biocides. A variety of formulations are used, including some
that contain glutaraldehyde.
Biocides may be used to control problem infestations of bacteria or mold.
Chlorine bleach is widely used by homeowners and building service per-
sonnel to control fungal growth on surfaces, and fungicidal formulations
