MAH_2019

Protocol for Conducting Measurements of ANSI/AARST MAH 2019 Radon and Radon Decay Products in Homes 10 Exception —Additional testing is not required when the cause for the discrepancy can be proven or when it is decided to proceed with mitigation . Note 1—While decisions to mitigate at any time are not prohibited, comprehensive testing aids confidence that decisions are not being made based on a faulty test device or unexpected conditions. Note 2—Tests conducted under heating season conditions are more likely to provide a clear characterization of potential radon hazards. Note 3—Longer test durations reduce the chance that short-lived temporary conditions in weather or building operations have adversely influenced test results. 7.3 Post-Mitigation Testing Protocol The following procedures are required for determining if additional mitigation efforts are warranted. 7.3.1 New construction Buildings constructed with radon-resistant features that have not been activated with a fan are to be tested in accordance with one of the testing strategies specified in Section 5 . Where radon resistant features include a fan activated system, the following additional procedures are required. 7.3.2 Testing to confirmmitigation effectiveness One or more short-term test devices are to be deployed to evaluate the initial effectiveness of the mitigation efforts. These short-term measurements are to be conducted no sooner than 24 hours after activation of a mitigation system fan or completion of other mitigation efforts. In addition, closed- building conditions, in accordance with Section 4 , are to be maintained 12 hours prior to short-term test periods and throughout the test. Testing is to be either: a) postponed until both conditions are met, or b) extended if testing with a continuous monitor where device features or other methods are to be used to obtain an average reading that represents no less than 46 hours of contiguous data collected after both conditions are met. 7.3.3 Where to retest after mitigation Testing is to be conducted in the same location(s) as the pre- mitigation test(s), or, as an alternative or additional test location, in the lowest level that could be occupied to help ensure the safety of current and future occupants who may use these areas. In addition, a post- mitigation test is to be conducted in the lowest livable area above any crawl space that is structurally isolated from occupiable or tested rooms. Informative Advisory —When an ASD system exhausts below the roof, it is recommended to conduct an additional test in the room(s) immediately adjoining the outside exhaust location.