For example, facility maintenance issues such as leaky roofs, heating, ventilation and air conditioning (HVAC) system mal-functions, ineffective cleaning or excessive use of cleaning products all affect the qual-ity of classroom air. In addition, typical classrooms can har-bor many sources of VOCs, including old carpet and furniture, flaking paint, glue used for art projects and formaldehyde used to preserve science specimens. These materials can all be the source of harmful gases and should be replaced, contained or eliminated. The EPA recommends facilities man-agers and maintenance personnel use IAQ-safe products for the classroom that are minimally toxic, water-based, odorless and easy to clean and maintain. The EPA also encourages building archi-tects and interior designers to use products that are not prone to moisture damage or mold growth. Fortunately, low-VOC paints, flooring, wall and ceiling systems and wood prod-ucts are becoming increasingly common and affordable. corrects baseline readings at certain inter-vals so that no recalibration or compensa-tion for humidity is necessary. Some advanced IAQ monitors also fea-ture low power consumption and provide long-term stability even in harsh environ-mental conditions. A study on air quality in a typical 700-square-foot classroom with 20 to 30 occu-pants ventilated by a standard HVAC sys-tem was recently conducted. In that study, the amount of VOCs in the classroom exceeded healthy thresholds within a matter of minutes after students arrived in the classroom. Measured values of VOCs in the class-room — correlated to parts per million of CO 2 — continued to increase during the first hour of instruction. While slight improvements over the next VOC Detection In addition to paying attention to source control, facilities personnel can integrate IAQ monitors with HVAC systems to reduce energy costs and to improve air quality. One way HVAC systems are activated is through the use of motion, light and heat detectors to signal fans to turn on and off. However, these systems simply respond to changes in the environment and not to changes in air quality. A second method is to install indoor air monitors that measure the amount of car-bon dioxide (CO 2 ) in the room and signal the HVAC system to circulate fresh air when CO 2 threshold levels are exceeded. Unfortunately, these systems cannot detect odors like those from a lunchbox left in a desk over the weekend or harmful VOCs emitted from old furnishings or other sources. The third alternative is to use IAQ moni-tors equipped with metal oxide semicon-ductor-based VOC sensors that reliably detect a broader range of VOCs. These IAQ monitors use a maintenance-free sensing element that automatically Circle Product Information no. 213 on page 32 www.cmmonline.com 47
CMM – Archives Nov 2010: 47
