What is the significance of having 5% of annual tests as blanks?

Having 5% of annual tests as blanks is crucial for ensuring accurate background measurement. Blanks are samples that do not contain radon and are tested alongside actual samples to establish a baseline level of radioactivity that may be present in the environment, separate from that attributable to the samples being measured. This helps in identifying any contamination or background radiation that could affect the validity of the readings.

By comparing the results of the blanks to those of the test samples, technicians can determine if the radon levels being reported are reliable or if they have been influenced by external factors. A proper understanding of background measurements is essential for accurately assessing radon levels in a given space, which is critical for health and safety evaluations. This practice reinforces the integrity of radon measurement operations, as it provides confidence that the results reflected in the testing accurately represent the radon concentrations present.