The report details radon mitigation research in schools conducted by EPA during 1989 and part of 1990. The major objective was to evaluate the potential of active subslab depressurization (ASD) in various geologic and climatic regions. The different geographic regions also presented a variety of construction types and heating, ventilating, and air-conditioning (HVAC) system designs that are encountered in radon mitigation of school buildings. A secondary objective was to initiate research in difficult-to-mitigate schools. The research led to the following major conclusions on radon diagnostics and mitigation in schools: (1) Schools have many physical characteristics that typically make their mitigation more complex than house mitigation, including building size and substructure, subslab barriers, HVAC systems, and locations of utility lines. (2) Important school diagnostic procedures and measurements include review of radon measurements and building plans, investigation of the building to assess potential radon entry routes and confirm information in the building plans, analysis of the HVAC system and its influence on pressure differentials and radon levels, and subslab pressure field extension measurements to determine the potential applicability of ASD. (3) ASD can be applied successfully in schools where subslab communication barriers are limited.

Project report 1 Includes bibliographical references (page 82). Microfiche.