What is one minimum requirement to ensure closed conditions during a radon test?

To ensure closed conditions during a radon test, one essential minimum requirement is to post a notice that indicates "Radon test in progress." This action serves as a clear communication tool to inform occupants and visitors that significant precautions must be taken during the testing period to maintain the integrity of the results. Closed conditions typically require that windows and doors remain closed, along with other restrictions like avoiding ventilation or changes to the building's normal air flow. Posting a sign alerts everyone in the home or building to be mindful of these testing parameters, thereby supporting accurate measurements of radon levels.

In contrast, conducting the test at night only doesn't inherently guarantee closed conditions throughout the day. Using an automated testing device might be beneficial for data collection, but it doesn't relate directly to ensuring that the environment remains undisturbed during the test. Testing only in the summer could introduce additional variables affecting radon levels that are not related to closed conditions. Hence, communication about the testing process is critical in maintaining the required conditions for effective radon measurement.