Protocol for Conducting Measurements of ANSI/AARST MAH 2019 Radon and Radon Decay Products in Homes 2 2.2 When to Test? Informative Advisories: 2.2.1 Test at the earliest opportunity. Homes can be tested at any time of the year. 2.2.2 Test whenever moving to a new residence To prevent the possibility of long-term exposure to a radon hazard, take the opportunity to test in association with moving into any new or existing home or dwelling. 2.2.3 Severe weather Avoid testing during unusual local severe weather if the test period is less than 4 days. When severe conditions occur during a test, retesting may be appropriate. 2.2.4 Seasonal considerations While some buildings respond differently to seasonal changes, tests conducted when a heating system operates both day and night are more likely to provide a clear characterization of potential radon hazards. 2.3 Testing Devices 2.3.1 Approved test devices required All test devices used for deciding if mitigation is warranted are to be listed by one of the following authorities for having proven to meet minimum quality requirements: a) the National Radon Proficiency Program (NRPP), the National Radon Safety Board (NRSB), or b) as required by local statutes for jurisdictions that have a program for evaluating and approving devices. Note—Minimum requirements for test device accuracy are published in ANSI/AARSTMS-PC “Performance Specifications for Instrumentation Systems Designed to Measure Radon Gas in Air .” 2.3.2 Test device instructions and appropriateness Test devices are to be used in compliance with both this standard and instructions provided by the manufacturer that relate to device-specific needs. Note—It is important to choose devices that are designed for conditions and duration of deployment. 2.3.3 Test device types (defined) As applicable to requirements in this standard, the following definitions shall be used: a) “Passive devices” are those that collect a time-weighted average and do not provide hourly readings. b) “Continuous monitors” are monitors that can integrate, record and produce reviewable readings in time increments of 1 hour, and can be recalibrated periodically. If a device is not capable of these functions or is not set to record readings each hour, it is functioning as a passive device and is not considered a continuous monitor under this protocol. Note—Section B of the attached MAH Companion Guidance provides descriptions of test devices. 2.4 Who Should Conduct the Test? Informative Advisory —Home owners are encouraged to test with either do-it-yourself home test kits or with a qualified radon measurement professional . When testing in association with a real estate transaction, it is encouraged that testing be conducted by a qualified radon measurement professional . Requirements for those who provide professional services are found in Section 8 .