RE: Biological Hazards
& Your Air Handling System
Dear Website Customer:
Recently there has
been a lot of publicity and discussion regarding anthrax and other biological
hazards. Our goal is to offer some useful facts and information in an
effort to help our readers better understand how they can protect themselves,
their families, and employees against biological hazards relating to their
heating, ventilating, and air conditioning (HVAC) systems.
FACT #1: The infectious
range for anthrax has been estimated at 175-225 spores in a cubic foot
of air. It's important to note here that in these recent cases, the most
damaging effects involved people who came into direct contact with anthrax-laced
mail. The anthrax spores themselves are quite light and, no doubt, the
act of opening the mail itself caused them to become airborne and spread
some contamination. Unfortunately, little can be done for the individual
actually handling the mail. However, several measures can be taken to
protect others from dangerous spores carried by the air handling and ventilation
systems in our buildings and homes.
FACT #2: It is important
to realize that contamination through the HVAC system is not a good way
to kill people, but it is a great way to scare them. Air handling systems
are one of the most effective ways of spreading any organism, and any
ill-intentioned individual could readily release spores into the outside
air intakes or return air duct of a building. In this unlikely event,
one would expect the filtration system to catch most of the unwanted elements.
may ask, "How can I be sure my family, employees, and I am being
Much of the answer
lies in proper maintenance and cleanliness of your system. Consider taking
these simple, common sense steps:
FILTRATION SYSTEM - The filtration system is the first line of defense
when unwanted elements attempt to enter the air system in a building.
Change filters regularly! Overloaded, plugged filters separate from
their housings, allowing unfiltered air to blow past. Upgrade to
the highest efficiency filtration possible, making sure to consider
that the proper airflow resistance for the mechanical system is
EVAPORATOR COILS - The evaporator coil and drain system are the
second line of defense. Clean coils provide moist surfaces to catch
unwanted elements, which then are washed down the drain along with
the condensate water. In this manner the spores are not be able
to germinate and spread contamination. One must ensure that the
condensate pan is not holding excessive water for this to be effective.
When additional protection
is required, many firms have installed accessories like In-duct Ultraviolet
Lighting which can be quite effective in reducing the total number of
contaminants. UV lights will kill anthrax and other viruses such as influenza.
As you read this, many companies are working to design and install UV
light systems to meet the public's needs. These systems have been in use
in hospital environments for years, and are know to decrease the spread
of airborn infectious elements.
Hopefully, this overview
of biological hazards in the air handling system will be of help in guiding
you to meet your company's needs. Please call me at 214.631.1010 or e-mail
if you have any questions or would like additional information. I'd like
to hear from you.
KAHN MECHANICAL CONTRACTORS
Ann R. Kahn