*2.1.4 Radon chamber*

A radon chamber is a container that houses a radon atmosphere for calibration of radon detectors and conduction of studies in the field of radon metrology. It consists of tools for relative humidity, pressure, and temperature, which must be at a constant range for calibration of radon detectors. **Table 1** summarizes the type, size, and accommodation capacity of radon chambers; furthermore, the radon generating source must be traceable to an international or national standard.
