Radon exposure in workplaces is regulated by the new legislation based on health protection against the risks derived from ionizing radiation exposure (RD 1029/2022), also reinforced by the protection measures detailed in the new Technical Code of Building (RD 732/2019). Legislative requirements and the increase in demand for air radon measurements have boosted the setting up of accredited laboratories and entities for this purpose. To guarantee the reliability and quality of the results offered, it is necessary for these entities to participate in intercomparison campaigns for radon measurements in air, as required by the UNE-EN ISO/IEC17025. The ISIRYM has been participating in national campaigns for the detection and measurement of radon concentration, according to ENAC accreditation for measurements in air. Recently, through funding from the GENERALITAT VALENCIANA (IDIFEDER/2021/047), a 1 m3 radon chamber has been purchased to verify radon measurement techniques. Therefore, the main objective of this research is the implementation of the radon chamber through the validation of passive detectors (electrets) and active detectors (Radon Scout Plus and Rad7) using the AlphaGuard calibrated detector as a reference. The sensitivity of the detectors into different concentrations of radon at standard environmental conditions is analyzed.