InterNACHI Certified Radon Tester study guide
InterNACHI Certified Radon Tester · Work through your exam, one topic at a time.
The InterNACHI Certified Radon Tester credential is a professional certification offered within the InterNACHI® membership and certification ecosystem. InterNACHI® describes itself as providing certification "to help you stand out from the crowd" alongside licensing support, and it offers members access to training and education through its online education platform. The InterNACHI Certified Radon Tester study guide has 6 sections and about 2,131 words.
01Radon Science and Health Effects
This domain tests the physics and health basis behind radon testing: what radon is, how exposure becomes dose, and which thresholds drive recommendations. Radon-222 is a colorless, odorless, radioactive noble gas in the uranium-238 series.
335 words, about 2 min02Radon Entry, Transport, and Building Dynamics
This domain tests how soil gas moves into a building and why the same house can test differently from season to season or floor to floor. Radon entry is mainly pressure-driven, not diffusion-driven.
383 words, about 2 min03Measurement Devices and Test Placement
This domain tests device selection, calibration, and placement so that a reported number represents the occupied space rather than a convenient shelf. Passive devices integrate exposure: charcoal canisters and charcoal liquid scintillation for short-term tests, alpha-track detectors for long-term tests, and electret ion chambers for either.
344 words, about 2 min04Closed-House Conditions and Test Protocols
This domain tests whether the home was operated under the conditions the result is supposed to represent: closed-house conditions, correct duration, and normal occupant activity. For a short-term test, keep windows and exterior doors closed for at least 12 hours before the test starts and throughout it.
353 words, about 2 min05Interpreting Results and Reporting
This domain tests whether a result is interpreted with the right comparison, uncertainty, and reporting language-not just whether it is above or below 4 pCi/L. A radon result is a concentration at the device location during the test period.
361 words, about 2 min06Mitigation Basics and Professional Standards
This domain tests the mitigation options a tester should understand well enough to report and refer responsibly, plus the professional boundaries around testing. The most common and reliable method is active sub-slab depressurization (SSD): a fan draws soil gas from beneath the slab through a suction pit and piping, venting it above the roof.
355 words, about 2 min