Terina Owen, Architecture
Indoor air quality within
buildings is dependent upon the ventilation systems and principles of intelligent
design and critical analysis in the use of non-toxic materials to prevent
pollution problems at the source. Ventilation systems are the main
line of defense to combat poor indoor air quality. Today, society
is experiencing higher numbers of people who are being diagnosed
with Multiple Chemical Sensitivity (MSC). This paper will address
the strategies that can be used to achieve a better indoor air environment.
Why is it important to breathe
quality air? We spend 90% of our time indoors (Bower, 1989:67), inhaling
into our lungs whatever is presently in the air. Although this may
not seem harmful at first, the accumulative effect can be serious.
More and more people are suffering from MSC, causing a decrease in the
productivity in the workplace, and in turn causing higher health insurance
premiums. Economically, this should be a societal concern in itself.
The causes of sick buildings are a combination of factors. One is
the offgassing of materials; the other is the poor ventilation systems
that exist in the sealed building. These buildings can also be seen
in the Pullman housing market. In the seventies when the oil crisis
occurred, people began to seal homes more tightly (Bower, 1987:7). This
has created a backlash that has left some in the general population struggling
to deal with an illness that has stifling repercussions on its victims,
and very little protocol when it comes to diagnosis. Proper and effective
ventilation systems are not the cure but they can affect the buildings
in a positive way. Many of the benefits of a well maintained and proper
ventilation system is less sick days, high productivity, and a healthier
living environment.
Indicators, Strategies and Benefits
The following
indicators (I’s in bold and underlined) measure progress
towards achieving sustainable indoor air quality. The strategies (S's
in bold) are recommended action to improve each indicator. The I’s
and S’s are followed by a
statement of the social, environmental and/or economic benefits.
I.4. Use better ventilation systems.
S.4.a. Design for natural ventilation.
Stack ventilation is a strategy
most often considered in early design phases of building. It is described
in Sun, Wind, and Light, as being the movement of warm air through
a structure to the top and cool air replacing it below (Brown, 1985:98).
One of the advantages to stack ventilation, is that it utilizes the natural
flow of air that exists outside of the structure, and brings it through
the structure naturally to refresh the air. This works well because
it utilizes fresh air from the outside. Several approaches are used
to enhance the effectiveness of the stack ventilation. One is to increase
the height of the room; the second is to design a stack into which warm
air will naturally flow up and out (Brown, 1985:98). This kind of
an approach is best used in new construction. A good example of using
stack ventilation as a strategy is in the new university housing being
built next to North Campus Heights. These are opportunities to improve
indoor air quality through natural means. Existing buildings may
pose the problem of having sealed windows. This strategy is best
utilized in new construction, like the new athletic center being built
for the students.
Cross ventilation works
under the same principle of utilizing natural airflow to ventilate and
cool a building. Cross ventilation is the application of both stack
and horizontal ventilation. One of the advantages to cross ventilation
is that it offers a cool breeze sensation within the structure (Brown,
p107). One of the problems with this particular strategy is that
it is not as effective in cold and hot seasons. WSU is defined as
having a temperate climate. If not effectively integrated within a comprehensive
management plan, this strategy may create a higher energy cost because
the lack of seals within the structures themselves. By using either
stack ventilation or cross ventilation, both strategies must rely on openings
which bring in quality outdoor air. If not effectively used, energy
maybe lost through these same openings. This in turn, may raise the
cost of energy to heat the building in colder seasons. Because Pullman
is a cold climate 4-6 months out of the year, these strategies must be
integrated into a seasonal management plan.
S.4.b. When mechanical ventilation is required, carefully place air
intake(s) in areas where there is the highest
level of exterior air quality (especially away from auto circulation,
parking and service areas).
As discussed in the previous
report by Janet Harden, the quality of air brought into the bilding is
a fundamental first step in creating quality indoor air. It is extremely
important to locate the building's air intake(s) in the best possible location,
preferably on the roof and far away from vechical exhaust from traffic,
parking, and loading docks.
S.4.c. Use higher levels of ventilation (and heat exchanger) in mechanical
systems.
Airs to air exchange are
also commonly known as heat recovery ventilators. In air to air exchangers
the two streams of cold and hot air never interact but do exchange heat
(Bower, 1989:93). This system takes the heat produced in the working
areas of a building and transfers it's heat to the cold outside air coming
into the building. In this manner a sealed building gets both the
advantages of a fresh air turnover, thereby creating healthier indoor air
quality, and also saving on the cost of energy to heat the outside air
coming into the buildings. The systems advantage is that it can be
used both for heating and cooling cycles. It has become a more popular
alternative to normal HVAC systems, in that the building is using the existing
heat in the building to maintain a comfortable temperature. This shows
itself as being a viable alternative to traditional HVAC systems on campus,
because it is compatible with many existing ventilation systems in older
buildings.
S.4.d. Use efficient mechanical systems.
Mechanical systems primarily
use ducts and plenums to cool and heat the various parts of the building.
A traditional HVAC system utilizes ducts and plenums of a structure to
direct air into individual spaces. This system has proven highly
inefficient in regards to energy use. It uses higher amounts of energy
than do some systems that rely on both mechanical and natural systems.
One efficient system utilizes the thermal energy in daylighting to heat
the building at night, and the cool night air to cool the building in the
heat of the day (Brown, 1985:157). The heat is stored in either a
trombe wall or a surface that absorbs heat. This can be achieved
through the selection of dark colors and material mass which exists in
concrete or masonry construction. The heat that is stored is redirected
with the use of fans, ducts, and gravity with a lower energy cost to the
user of the building.
I.5. Use high quality filtration systems for each specific situation.
S.5.a. Use higher exchange rates per hour in mechanical systems.
Most mechanical systems
are inefficient in that the air exchange rate is not enough to ensure a
cleaner indoor air quality. This is primarily due to the fact that
building code only requires an air turnover rate of two per hour (Dadd,
1992:174). This in itself may set up an indoor air pollution problem..
In order for the mechanical systems to work, there has to be a higher turnover
rate for air exchange per hour. In some mechanical systems, the air
exchange takes place only minimally and is mixed with exhaust air (Dadd,
1992:174). In order for WSU and Pullman to achieve a better indoor
air quality, steps must be taken to introduce a higher exchange rate per
hour with air to air heat exchanger in all new and existing mechanical
systems.
S.5.b. Supply quality filters for situations requiring specific ventilation.
Air pollution falls into
two categories: one is the toxic gases present in the air, and the second
is particles that are present in the air. Specific filters have to
be used in specific situations, meaning that if the air exchange unit is
located near a parking garage, where large amounts of carbon dioxide may
be introduced into the indoor air, specific filters have to be used to
compensate for these pollutants. There are four basic filters, each
can be used for specific situations. The first is the activated carbon
filter which works best for absorption of various gases. The second
type of filter uses mechanical filtration and works on the principle of
trapping particles using mechanical means. The downside to these
kind of common filters is that they are petrol based (Dadd, 1992:36), thus
defeating the purpose of a green campus. The third type of filter
is an electrostatic filtration. This is a system that attracts particles
through electric attraction. The fourth filter that is commonly used
is the negative ion generation, which only attracts certain particles in
the air (Dadd, 1992:36). By using one of the four basic filters in
the correct situations, indoor air quality can be improved. A good example
of this would be at Carpenter Hall, on the WSU campus. Using a carbon
activated filter within the air exchange will cut down on the amount of
carbon dioxide that enters the building from the auto exhaust fumes.
By using a standard filter in the air to air exchange, not only does the
system allow car fumes in but also cigarette smoke. By using the
right filters for the right situation, we will in turn improve the indoor
air quality in our buildings.
1.6. Maintain ventilation systems to promote better health
and efficiency.
S.6.a. Correctly install and maintain filters.
S.6.b. Properly maintain systems.
Correct installation and
maintenance is often the culprit of bad indoor air quality.
When mold is allowed to grow within the duct system, spores are released
into the air and contaminate the system. When filters are not regularly
changed and checked, serious air pollution can occur. With all the
possibilities of contamination within the system, it is important to design
the system to allow access to ducts and filters. Limited space and
access is a problem that is seen in many buildings. One of the ways WSU
can deal with this problem is by regularly maintaining existing systems
and properly installing new mechanical systems.
Conclusion
As we search for the solutions
to indoor air quality, the questions still remain about how far the affects
will reach. Multiple Chemical Syndrome (MCS) and Sick Building Syndrome
are all preventable problems through proper design. The indicators
and strategies dealing with proper ventilation, maintenance, and proper
filtration are important starting points for improving indoor air quality.
By properly maintaining a system, and by using intelligent design, we can
create the best possible indoor air quality for our active community.
References
Link: www.mit.edu/bt/www/bt/iaq.htm
Bower, J., 1989. The Healthy House. Carol Communications.
Brown, G. Z., 1985. Sun, Wind, and Light. Wiley and Sons.
Dadd, D. L., 1990. Nontoxic, Natural, and Earthwise. Tarcher, Inc.
Dadd, D. L., 1992. The Nontoxic Home and Office. Tarcher, Inc.