Fiber year
The fiber year is defined as the product of the concentration of one million asbestos fibers of critical dimensions (i.e. asbestos fibers with a diameter of less than 3 µm and a length of more than 5 µm; WHO fibers ) per cubic meter of air at the workplace for 240 working days for one year, eight hours a day .
The term is used in the assessment of asbestos-related occupational diseases (BK No. 4104). 25 fiber years are e.g. B. in Germany a criterion for the recognition of bronchial carcinoma as an occupational disease.