MALB_2014 with 1-21 Revisions

Normative Appendix C ANSI/AARST MALB-2014 with 1/21 Revisions C— Radon Sources Other Than Soil Gas 2 C-2 Clearance Testing Upper Floors Actions required for clearance testing after efforts to mitigate radon hazards on upper floors shall include requirements in a) and b) of this Section C-2 . C.2.1 Radon from soil gas Where efforts to mitigate elevated radon concentrations on upper floors included mitigation of soil gas entry into the building or other mitigation method for addressed ground-contact locations, clearance testing shall include: a) Clearance testing as required with Section 7.3 , and b) Testing all upper floor locations where elevated radon concentration have been observed. C.2.2 Radon from Building Materials or Inadequate Ventilation Where elevated radon is identified to be caused by building materials or inadequate ventilation, post- mitigation clearance testing shall be conducted for: a) All dwellings and non-residential rooms where efforts have been made to mitigate radon from building materials or address inadequate ventilation; b) All locations not tested but that demonstrate similar potential for causing elevated radon concentrations; and c) Where mitigation efforts include enhanced ventilation techniques, post- mitigation clearance testing shall include seasonal verification in accordance with Section 7.3.2 b within the first year of occupancy or ownership of property management. C.2.3 Radon fromWater Supplies Where mitigation efforts included reducing radon in water supplies, clearance testing shall include: a) Duplicate measurements of radon in water for both untreated and treated water in accordance with ANSI/AARST MW-RN Protocol for the Collection, Transfer and Measurement of Radon in Water ; and b) Testing indoor air for radon in one or more locations within each unique area where elevated radon has been found.