Middle-East Journal of Scientific Research 21 (12): 2243-2246, 2014 ISSN 1990-9233 © IDOSI Publications, 2014 DOI: 10.5829/idosi.mejsr.2014.21.12.21879 Corresponding Author: Amir Hossein Hashemian, Department of Biostatistics and Epidemiology, Kermanshah University of Medical Sciences, School of Public Health, Kermanshah, Iran. 2243 An Introduction to Sound Spectrum Level: Spectrum Analysis Hajiali Yartire, Amir Hossein Hashemian and Saman Mohammadi 1 2,3 4 Department of Occupational Health, Kermanshah University of Medical Sciences, 1 School of Public Health, Kermanshah, Iran Research Center for Environmental Determinants of Health (RCEDH), 2 Kermanshah University of Medical Sciences, Kermanshah, Iran Department of Biostatistics and Epidemiology, Kermanshah University of Medical Sciences, 3 School of Public Health, Kermanshah, Iran Department of Occupational Health, Kermanshah University of Medical Sciences, 4 School of Public Health, Kermanshah, Iran Abstract: Noise is recognized as an occupational pathogen with physical origin being studied from different types each of which has its own advantages. Since few studies have been conducted on some types of these studies, such as spectrum centroid level, the objective of this study is to provide the ground for scientific and industrial communities to promote knowledge development in this regard. For the purpose of the present study we divided Bakhtar Felez Profile and Tank Construction factory to 90 sound stations with area of 3×3 m . 2 Frequency analysis is carried out with one-third octave analyzer in active stations. In the third step, we facilitated comparison of risk exposure possibility at each station through assessing spectrum centroid level and statistical analysis. The obtained data are analyzed using SPSS software (version 21). The number of active station is less than half indicating congestion of workload. Stations with high sound sound spectrum level are situated at places with bass or law audio frequency level which needs a great concern. Research findings represent a significant inverse correlation (r = -0.54, p<0.001) between spectrum centroid level and frequencies. Comparison of spectrum centroid level based on classification of frequencies is indicative of significant differences at sound spectrum levels under/over 512 and 2048. But there is no significant difference between spectrum centroid levels divided based on frequency classification or being under or over standard level. Although, in some stations, spectrum centroid level is much higher than standard level and located in places of bass and mid frequencies, sound spectrum level average is 69.42 dB which is less than standard level. Key words: Noise Frequency analysis Bakhtar Felez Sound spectrum level INTRODUCTION Among actions that are usually taken in respond to Noise is recognized as an occupational pathogen measurement and comparison of sound pressure level at attracting scholars attention, especially after the industrial stations where worker are working temporary or revolution and being studied from different angles permanently. In this case, an area of sound station is including the objections of practitioners exposed to it. determined based on several factors. Then, sound Nowadays, practitioners' knowledge of health problems pressure level of the station is measured. The obtained has increased which also leads to increased complaints in data can be used for the intended purposes. this area. Consequently, professional health experts There are different ways of noise measurement in should focus on these complaints to have a fair scientific sound stations. The most common form is to measure judgment based on observed facts enabling them to sound pressure level, regardless of sound frequency, protect the public while answering their questions. using sound level meter calibrate at a frequency of 1000 practitioners complaint about noise are calculation,