Standard for outside air dampers

JSPAK

ever since i started working for a school system 15 years ago . getting sick sick sick .... 14 schools and poor air quality ..... sickness seems to spread thru schools .... colds flu's viruses ect ect ... what is the standard for outside air on the air handlers and anyone got any good links where i can learn more .... like 15% outside air ect ect. or so much turnover of fresh air coming into school. in otherwords whats the best solution to make the schools healthy .... is there a national or statewide standard .. i live in ct

Steamhead (in transit)

Most states

have laws or Codes that specify minimum outside air in schools. That's where I'd look first.

If your system is delivering the proper amount of outside air, I would look for mold or other primordial life forms in the ductwork.

This is one more reason why the industry was moving away from ducted heating systems up until the end of World War II. After the war, builders went with whatever was cheapest, since they didn't have to live with the messes they created.

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wsdave

Here's a start

And it is free to boot......

http://www.epa.gov/iaq/schools/actionkit.html

HTH

Dave

Brad White

School Ventilation

Steamhead is right, the code is the place to look. Look deeply in that several states may still have "schoolhouse codes" on the books. Massachusetts used to have such a code where the regular code stated 5 CFM per person and for schools 7.5... confusing I know. I will mention MA as a point of reference only. CT may vary but most state codes use a reference standard. In this case ASHRAE 62 and even then the version may differ.

Current code and standard of care in MA for classrooms is 15 CFM per student while certain cities and towns say 20... then 25 in science or art classrooms because of chemical use.

20 CFM per person is a normal standard for most occupancies and the 15 CFM value reflects places of assembly. That may seem counter-intuitive (more people and less air per) but the reality is rooms are not occupied at the full design rate nor for long. The reduction is a compromise between good ventilation and energy use.

In a typical classroom using a unit ventilator for example, our default standard is 375 CFM for 25 people (23 students plus one teacher and one aide), up to 500 CFM if a 20 CFM standard is used. This is adjusted of course as needed.

On top of this, use of CO2 monitoring to reduce ventilation when the CO2 levels drops saves energy.

Keep something in mind here: You could have 100% outside air ventilation and not see much reduction in sickness. Airborne aerosols from sneezes are one part but hand contact and children especially are incredibly efficient vectors for disease. (This is why we sometime call them "the little sh*ts

Sneeze, wipe hands, ruffle your friends hair, wrestle with that girl you really like but cannot say... wipe nose, use the bathroom, forget to wash hands... need I go on?

Ventilation itself without proper filtration will bring in as much in the way of spores as it may dilute airborne viruses.

I am all for good ventilation but the rate above code to reduce airborne illness will cost you a lot of energy. Ventilation addresses one aspect but not the worst one of disease transmission.

EDIT: You did ask re: dampers. We specify Ruskin, Arrow and Tamco (T.A. Morrison company) out of Canada as excellent insulated dampers. Ruskin has an offering with a built-in air measurement system. For low pressure drop, you cannot beat Ebtron though, in my book.