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These areas present a unique challenge to the HVAC system. One of the most expenditure sensitive areas of an educational facility, the investment in materials (books) must be considered, along with the environmental protection for occupants. To protect occupants, ASHRAE 62-1989 recommends outdoor air ventilation at a rate of 15 CFM per person (based upon 20 persons per 1,000 square feet)7. The minimum filtration efficiency should be 30-35% dust spot as defined under ASHRAE Standard 52.1-1992. Like an auditorium, a library is considered a place of assembly for air filtration and HVAC requirements.
To protect the facility's investment in books, carbon should be considered for library applications. Ozone, a common contaminant existing everywhere, is a detriment to artifacts, paintings and books. The primary area of concern relates to deterioration of bookbindings. Ozone may be reduced through the application of activated carbon. Carbon reacts with ozone (O3) in catalytic manner and reforms ozone to nondetrimental oxygen (O2). Outside air may also be reduced to 5 CFM per person by the application of the Farr Two -Step Design Solution. Occupants will also benefit from gaseous contaminant protection designed into the system to protect the books. If this method is used, two stages of pre-filtration are recommended, a 30-35% prefilter and an 80-85% secondary filter (dust spot as defined under ASHRAE Standard 52.1-1992).
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