The fundamental aim of this study is to compare between the noise generated by rotating machines in GP1/Z plant in the industrial zone of Arzew (Algeria). At present, noise is an integral part of our environment; it represents a serious challenge because of its dangerous health effect. Although, in Algeria many studies have been carried out concerning noise pollution due to transport (road, air and rail traffic) but, only few have dealt with the case of industrial noise. The study of noise generated by rotating machines in industrial units is a complex problem that requires in-depth research to determine noise sources, on-site measurements, noise mapping and solutions to this problem. This is the main objective of this work. In order to study and evaluate the impact of the noise generated by rotating machines in the GP1Z plant, we used an engineering method, called simplified method. Simulation was done based on Code-TYMPAN software. The results of our study show that the average noise level generated by rotating machines at the GP1/Z complex is unacceptable compared to the standard. We have also shown that noise measurements exceeding danger ratings have been identified approximately noisy installations (rotating machines). We also pointed out that the situation will exacerbate if there wouldn't provisions in the near future.