Tehran University of Medical Sciences International Journal of Occupational Hygiene 2008-5109 3 2 2011 12 15 49 55 Rostam Golmohammadi Department of Occupational Hygiene, School of Public Health and Center for Health Research, Hamadan University of Medical Sciences, Iran Mahbobeh Eshaghi Department of Occupational Hygiene, School of Public Health, Hamadan University of Medical Sciences, Iran Mehdi Reyahi Khoram Department of Environmental Engineering, Islamic Azad University- Hamadan Branch, Iran. 2015 10 04 At present, conventional methods of noise exposure assessment utilize in industrial workplaces. In the classical area assessment method, noise exposure assessment depends on sound pressure level measurement results that expressed numerically and indicated  harmful areas. This paper proposes an exposure assessment method of occupational noise based on Fuzzy sets. The noise assessment by Fuzzy logic method involves the primary investigation of the workplace, determined inputs and output variables, Fuzzification, Fuzzy rules, Fuzzy inference method and Defuzzification. This assessment method considered a function consists of Noise level, the number of exposed workers, exposure duration and noise reverberation time. Suggested method makes possible to evaluate unconsidered cases in order to assess of noise exposure risk. Fuzzy logic assessment results are more useful and flexible for analysis than conventional assessment. Fuzzy logic provides the opportunity to obtain risk model of noise exposure based on noise parameters, dimension of workplace and human perceptions. https://ijoh.tums.ac.ir/index.php/ijoh/article/view/34 https://ijoh.tums.ac.ir/index.php/ijoh/article/download/34/34