New Relocatable Classroom Field Study
Four new RCs were constructed by the manufacturer for use at the two schools in the fall semester, 2001. Two standard classrooms utilized the standard materials and two modified classrooms employed the alternate materials. For a case-crossover design, each classroom was equipped with a standard HVAC system and an advanced system employing indirect/direct evaporative cooling (IDEC) and hydronic heating to provide continuous ventilation of at least 15 cfm per occupant (Apte et al., 2002). At each of the two schools located in different districts, a modified classroom was sited adjacent to a standard classroom. These classrooms were fully instrumented and fitted with built-in sampling equipment. In the fall 2001 semester and again in the spring 2002 semester, integrated school-day indoor and outdoor aldehyde and VOC measurements were made weekly over two to three months with the HVAC systems switched on alternate weeks. Energy and environmental parameters were measured continuously.

VOC Concentrations in New Relocatable Classrooms
When the advanced IDEC system was selected, it provided a continuous outdoor air ventilation rate of approximately 19 cfm per occupant irrespective of the need for heating or cooling. The effectiveness of the IDEC system was evidenced by relatively low carbon dioxide concentrations in the classrooms. However, some variation in the way in which the teachers utilized the HVAC systems was noted. The ranges of concentrations of selected VOCs measured in the fall 2001 semester when the classrooms were operated with the IDEC system are presented in Table 23. As predicted, caprolactam concentrations were very low in classrooms fitted with Nylon 6,6 carpets. Measured formaldehyde concentrations ranged up to values in excess of predicted concentrations in the standard classroom at School A and in the modified classroom at School B. A portion of the elevated formaldehyde concentrations in the School B classroom was attributable to the introduction of teaching aids (peg boards and marker boards) constructed of composite wood products. The standard vinyl covered wall panels turned out to be lower sources of toxic VOCs than predicted from the laboratory study of VOC emissions.