The Calibration Laboratory of the Paul Scherrer Institute is responsible for the calibration and verification of radiation protection instruments and dosemeters for internal as well as external customers, such as nuclear power plants and hospitals. The Laboratory is authorised by the Federal Institute of Metrology METAS to perform legal verifications and is accredited as an inspection body, according to ISO 17020, and as a calibration laboratory, according to ISO 17025 by the Swiss Accreditation Service. In addition to routine activities (e.g. calibration of dosemeters, irradiation of passive and active dosemeters on phantoms), the Laboratory is involved in various research and development projects with the goal of supporting the increasingly complex calibration needs and to comply with new regulations, particularly those related to clearance limits in free release measurements. Here we present an overview of the currently on-going projects, which include the investigation of Monte Carlo methods for the calibration of clearance monitors and the development of new calibration procedures for wipe test counters. We also discuss the challenges encountered in these projects, since different stakeholders, ranging from legal authorities to equipment manufacturers and users, are involved in the calibration process.