MAMF_with 1-21 Revisions

Normative Appendix C ANSI/AARST MAMF-2017 with 1/21 Revisions C— Radon Sources Other Than Soil Gas 1 NORMATIVE APPENDIX C RADON SOURCES OTHER THAN SOIL GAS C-1 Follow-up Procedures Where elevated radon concentrations are found in upper floor test locations or other locations where there is evidence that soil gas may not be the cause, an evaluation shall be conducted for whether unusual soil gas migration, building materials, water supplies or inadequate ventilation are the cause of elevated radon concentrations. C.1.1 Process of elimination As a step-by-step process of elimination, it shall be permitted to mitigate known or suspected sources of radon gas, such as soil gas in ground contact areas, prior to initiating evaluations of upper floors or other locations. While flexibility is permitted for procedures and the order they occur, the evaluations shall focus on lines of evidence for characterizing radon hazards throughout the building. C.1.2 Upper Floor Evaluations Where elevated radon concentrations are found in upper floor test locations, efforts for initial or follow- up measurements to characterize upper floor areas of the building shall include: a) a radon measurement conducted in all dwellings and nonresidential rooms intended for occupancy on the floor closest to ground where elevated radon concentrations were found, and b) a radon measurement conducted in all dwellings and non-residential rooms for no less than one additional upper floor, whether or not elevated radon concentrations were initially found there. A report that complies with Section 8 Test Reports shall be provided with test results and recommendations or guidance consistent with the findings of this characterization. C.1.3 Localized ventilation or building materials Where initial characterizations, such as conducted in Section C.1.2 for upper floors, indicate inadequate ventilation or building materials specific to certain dwellings or rooms are the problem: a) a visual review shall be conducted and reported in writing for all other locations in the building where lack of ventilation or similar building materials could be the cause of elevated radon concentrations; and b) Confirmation that these conditions are the cause of elevated radon concentrations is not required. However, it shall be permitted to attempt confirmation by simultaneous radon measurements: 1. in a room where poor ventilation or building materials are suspected as the cause, and 2. in a nearby room suspected of having radon concentrations that are below the action level . C.1.4 Building materials common to the structure If measurements indicate building materials common to the entire building or portion of the building are the problem, the measurement evaluation shall be repeated on one or more additional upper floors unless there is reliable evidence to support a different course of action. Where measurements support the likelihood that building materials common to the entire building or portion of the building are the problem, reports shall recommend mitigation for all floors. C.1.5 Radon in water Where radon in water is suspected to be the cause of elevated radon concentrations in air, measurements for radon in water shall be conducted in accordance with ANSI/AARST MW-RN Protocol for the Collection, Transfer and Measurement of Radon in Water .