What is the minimum distance that duplicate tests should be placed apart?

The minimum distance for placing duplicate tests is recommended to be at least 4 inches apart. This spacing helps to ensure that the tests do not influence each other, which could skew the results. When tests are placed too close together, they might experience similar environmental conditions, leading to correlated readings that do not accurately represent the radon levels in different areas of the space being tested. By maintaining a distance of 4 inches or more, it provides a clearer and more reliable assessment of radon concentrations, facilitating better accuracy in data collection and analysis. This practice is essential in ensuring the reliability and validity of radon measurement efforts.