Camfil Farr Product Catalog - Texas Air Products

3
Air Filter Technology
Airborne Contaminants and Indoor Air Quality
Building maintenance problems caused by microorganisms include odor,
staining, and deterioration of interior surfaces, such as ceilings, walls,
carpets, draperies, and other surfaces. Microorganisms also contribute
to corrosion, which is responsible for billions of dollars worth of damage
to our buildings each year. We can all relate to the discomfort from
mildew odors and the costs involved in removing the damage to
surfaces affected by their growth.
Poor indoor air quality is often the result of inadequate ventilation
strategies that are directly traceable to rising energy costs. Building
managers have changed the manner in which they operate their HVAC
systems, and the systems themselves are constantly being modified for
greater energy efficiency. Some of these changes have led to a
reduction in the level of ventilation:
• Buildings are operated with a higher percentage of recirculated air and
an inadequate fresh air supply, sometimes as little as 1.0%.
• Buildings are tightly sealed to reduce infiltration. In years past, building
leakage often made up for HVAC system ventilation deficiencies.
• Variable air volume systems may operate as low as 25% of the design
airflow.
• Other operating and maintenance practices can also add to serious
indoor air quality problems.
With today’s economic operating restrictions, a building’s maintenance
budget is often one of the first casualties when cuts are required. The
following maintenance practices can lead to poor indoor air quality:
• Completely shutting down the HVAC system at night and on weekends.
Under humid conditions, condensation can build up inside ductwork. If
dirt is present in damp ducts, spores, mold, and bacteria can flourish to
be spread throughout the building when the system is started.
Unfortunately, the dust accumulation and growths of mold, bacteria, etc.
are hidden inside the ductwork. Fan systems that start and stop
throughout the day may cause more dirt and contamination to be
dislodged and carried into occupied areas.
• Increasing the levels of improperly filtered, recirculated air, that
continually redistribute the gaseous and particulate contaminants within
the building, allowing them to grow to unacceptable levels. There is a
cumulative effect on occupant discomfort throughout the day and the
week because of increased levels of contamination.
• Reducing housekeeping procedures results in more dust and dirt in the
building.
• Switching to lower cost, lower efficiency filters to reduce pressure
drop and save on replacement filter costs means that more particulate
contaminants are carried throughout the building and allowed to build to
unacceptable levels.
• Lowering ventilation rates may result in lower building humidity levels
in some geographic areas during certain seasons, and this may affect
eye, nose, throat, and skin conditions of occupants.
• Maintaining buildings at higher temperatures in the summer and cooler
temperatures in the winter.
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• Increasing use of synthetic construction materials and furnishings that
can be the source of gaseous contamination (commonly referred to as
off-gassing).
Additionally, any area of excessive moisture must be addressed.
Sources of water in an HVAC system must be eliminated or controlled.
Condensate drain pans should be cleaned periodically. Drains should be
free of obstruction, and the entire HVAC moisture removal system
should be checked periodically to assure the elimination of freestanding
water.
Some areas require additional consideration. Laboratories, industrial
technology shops, locker rooms, copier or printer rooms, photography
darkrooms, and toilet areas should be under negative pressure to
prevent contaminants from spreading to other areas of the building. A
slight inward air velocity of 100 feet per minute is all that is required and
may often be addressed with a small venting fan. Additionally, copier
rooms should have filtration capable of 65% efficiency at removing
particles 0.3 micron in size.
If you have problems in your facility be proactive:
• Address the issue immediately and apply corrective action. Do not
discount your building occupant’s ability to understand the problem.
There is a wealth of information available, including the Internet,
specifically addressing this problem.
• Assign an individual to monitor problems and form an action
committee to work with your health, facilities, and administrative
personnel. Maintain a data tracking system to avoid repeats of problem
situations and document corrective actions.
• Involve people in your facility by educating them about IAQ red flags
for buildings and their occupants. Teach HVAC basics, such as proper
operation of unit fans and the importance of not blocking registers
(returns and supplies).
• Enlist the aid of competent outside experts. Many product vendors
can address proper IAQ and will often supply speakers for local
meetings.
The cost of providing proper indoor air quality can be more than offset
by:
• Reduced absenteeism.
• Reduced building deterioration and maintenance.
• Prevention of complaints based upon environmental problems that can
often result in strained relationships.
• Reduction of liabilities.
• Increased productivity.
As part of our program for continuous improvement, Camfil Farr reserves the right to change specifications without notice.