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"HVAC &
Educational Facilities Part 1 of 3"
The Comfort Zone
March / April 2001
by Maury Tiernan |
The Comfort Zone column, written for this mobile/modular industry magazine,
normally deals with the challenges related to HVAC systems in commercial
factory built structures. This is the first of three articles focused on issues
that arise involving HVAC systems in educational facilities. This discussion
will pertain to site built as well as commercial factory built schools.
The same air comfort issues arise in every educational facility across the
country at one time or another. It doesn't matter in which part of the
continent you reside, what type of HVAC system you have, or what your climate
is like. If you are a facility or maintenance director, superintendent, or
health officer, you either have had, do have, or are about to face the
following issues.
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Mold
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Teachers/Students with headaches
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Poor ventilation
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Wide Ranging Indoor Air Quality problems
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Rising Energy Costs
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Noisy HVAC units and systems
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Pesticide problems
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Formaldehyde off gassing
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HVAC maintenance procedures
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Biological contaminants
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Outdoor Air Quality near ventilation intake
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Volatile Organic Compounds
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Aesthetics of HVAC units
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Energy codes
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Air filtration
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Air purification
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Teacher complaints too hot/cold
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Electronic Thermostat programming
These are just some of the obvious issues that all of you in the educational
field deal with every day. I am sure you could quickly double the size of this
list.
We will not be able to exhaustively review and solve all of these issues in
these three short articles, however we will address a good majority of them
because several of the topics cause or effect others. For example, lack of good
ventilation (outside air) practices may cause teacher headaches, and contribute
to many IAQ problems. On the other hand, ventilation may introduce diesel fumes
or sewer gas into the classroom, or raise maintenance cost, filter changing,
and energy costs.
So let's start our look at the classroom "comfort zone" with a closer look at
ventilation. During the energy crisis of the late 1970's, building code
officials implemented many changes in the building codes to lower energy
consumption. Tightening the building air leakage, and reducing the ventilation
(outside air) rate to 5 cfm/person were two of those changes. Then came the
1990's, with indoor air quality (IAQ) problems abounding, and code officials
responding with a change in the minimum ventilation back to 15 cfm/person of
outside air. But what about all those schools built from 1970 to 1994, and all
the maintenance personnel trained in that time frame to caulk everything up,
close ventilation devices, save energy, etc? Today's story is different. We are
currently educating school districts to bring in a minimum of three times more
outside air than they have in the recent past. Hearing this, some experienced
HVAC professionals think "triple the energy use," increased maintenance,
increased costs. Couple this reaction with a new energy crisis looming in 2001,
and it seems we are condemned if we do, and could be sued over IAQ issues if we
don't.
This writer believes that whenever there is a complaint about headaches,
pesticide smell, formaldehyde off gassing, etc., improving ventilation (outside
air) is the easiest, cheapest, and first remedy that should be implemented.
Why? Because it is the easiest controllable and manageable first remedy. Make
sure you provide a minimum of 15 cfm/person (intake and exhaust) of "good"
outside air, continuously, during occupied school hours. This point is in bold
type not only to emphasize it's importance, but also in hopes that this phrase
makes it into your facility specifications. Ventilation is not the only answer,
but it is the easiest one over which you have immediate control, and with it
you can provide an instantaneous "bandaid" to congruent problems.
For example, although it cannot change a pesticide chemical composition or when
the pesticide was applied, ventilation does blow out fumes after they have been
sprayed, providing that short term "bandaid" of clean air until you can change
the product and time of application. Likewise, ventilation does not remove the
formaldehyde from the furniture, but it does blow the off gassed formaldehyde
out of the room. Ventilation (outside air) can reduce the occurrence of
headaches experienced in a classroom (for may reasons), and ventilation does
improve the learning environment for the students. Ventilation is as simple as
opening a window or door, or turning on your HVAC system fan, which allows some
conditioning of the outside air when it is introduced.
The ventilation (outside air) rate of 15 cfm/person is the minimum recommended
rate established by the American Society of Heating, Refrigeration, and Air
Conditioning Engineers (ASHRAE) under their Standard 62-1999. What do we need
to know to insure that the ASHRAE standard is being met?
If mechanical engineers were originally involved in your school project, they
have probably included ventilation and a balance test of the HVAC system upon
commissioning of the building. This does not mean however that your current
ventilation meets the ASHRAE standard, today. Many times the maintenance
personnel change the ventilation setting after commissioning of the HVAC
equipment to reduce the need for filter changes, to reduce the introduction of
cool/hot outside air when the system is not heating or cooling, to save
maintenance cost or energy costs. Facility and maintenance personnel do not
fully realize the liability and "educational" costs of such actions.
Then, how do we know or insure that we are currently meeting, and not (costly)
exceeding the 15 cfm of outside air per person? A semi annual or annual
verification of ventilation device settings should be added to your maintenance
checklist. Every district should have at least one air flow hood to regularly
check the HVAC unit or unit ventilator for proper outside air intake and
exhaust. If you have a classroom with 20 students you only need 315 cfm outside
air, and with 30 students you will need 465 cfm of outside air. With a very
large HVAC unit or unit ventilator, simply count up the normal average daily
attendance with teachers and multiply by a minimum of 15 cfm/person of outside
air.
Where would the maintenance personnel check that the ventilation requirements
were being met? There are many different types of HVAC systems in our schools:
boilers, chillers, package roof/ground mount, split systems, wall mount, inside
type wall mount, etc. Some of these systems have integrated ventilation
options; others do not. Each and every classroom does require ventilation. How
it gets there will vary. After you determine the ventilation method used, find
out the occupant load it serves, then use an air flow hood to measure the
ventilation amount. (Check the insert box below for an air flow hood source).
If your ventilation device is not meeting the required rate, check out whether
the ventilation device is incorrectly sized or whether there is an adequate
means of exhaust. If the air is going in, it must be able to go out (exhaust)
somewhere for the system to function well.
Ventilation requirements are just one piece of the indoor air quality puzzle.
Today with these issues in the media, having a good indoor air quality program
at your school district is imperative. If you don't have an IAQ program today,
you will need one soon, or you may already have some practices in place, but
not a formal program. How will you address a phone call from a teacher or
student who claims they have regular headaches in the classroom? One California
school district (without an IAQ program in place) didn't understand the
ramifications of the "headache phone call," and ended up spending 0,000 to
mitigate the snowball of events that followed.
The Environmental Protection Agency has an information clearinghouse website
that will help you with IAQ information. They also have an INDOOR AIR QUALITY
TOOLS FOR SCHOOLS ACTION KIT available for school districts. If your district
doesn't have an IAQ plan, order one of these kits. If you do have a plan, order
one of these kits anyway, and check it against your district's plan. The kit is
an excellent "tool for schools" to deal with IAQ issues of all kinds. It
contains all of the guides, checklists and forms your district will need for
teachers, an IAQ coordinator, health officials, administrators, maintenance
personnel, and food service personnel to respond appropriately to all types of
IAQ problems when they arise. There is even a problem-solving wheel included.
Check the insert box for related websites and product information.
Until the next time we meet, stay well ventilated in . . . The Comfort Zone.
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