If closed-building conditions were not maintained for 12 hours, how long must the conditions be maintained before initiating the radon test?

To initiate a proper radon test, it is essential to maintain closed-building conditions for at least 12 hours prior to the test. Closed-building conditions mean that all windows and doors should remain closed, and the heating or cooling system should operate normally without any windows being opened or external air being allowed in. This ensures that the test accurately measures the radon levels present in the home without the influence of external factors.

In the context of the scenario where the closed-building conditions were not maintained for the 12 hours leading up to the radon test, the requirement to re-establish those conditions for another full 12-hour period is necessary to ensure the reliability of the test results. Therefore, the answer being 12 hours indicates that a complete reset period is required for accurate measurements, aligning with best practices in radon testing protocols. This thorough maintenance of conditions allows for a consistent measurement free from variations caused by outside influences.