The emission of the UV source must be checked (at least) annually for compliance with the given acceptance limits by a suitably qualified expert. The inspection should be conducted with a spectroradiometer that has been calibrated against an internationally accepted calibration standard (e.g., endorsed by an institution that is certified by the European co-operation for accreditation EA). On an on-going basis, the emis-sion of the UV source must be monitored radiometrically (e.g. with an integrated UV meter) before every session of usage. In parallel, the radiometer(s) and / or UVA cell(s) (employed for measuring and / or adjusting the irradiance of the UV source at sample level and calculating the UV doses), will be calibrated in terms of UVA irradi-ance (W m-² UVA, 320-400nm) for the same UV source spectrum, according to the Colipa recommendations given in the Guideline "Monitoring of UV light sources" (2007).