Evaluation of Noise Pollution Before and After Performing Corrective Measures in Operational Units of Reservoirs and Petroleum Products Transportation of Abadan Oil Refinery



Mousavi SM¹ ; Moradirad R² ; Beheshti MH³ ; Hajizadeh R⁴ ; Taheri F⁵ ; Khodaparast E⁶ ; Yazdanirad S⁷ ; Torshizi YF⁵ Show Affiliations
Source: Iran Occupational Health Published:2019

Abstract

Background and aims: Noise exposure as a main problem of industrial world is one of the most common risk factors in industries and many employees expose to it in the workplace. Noise exposure causes a wide range of the discomforts, disorders, and occupational diseases and effects including focus loss, systolic blood circulation changes, sleep disturbances, long-term memory loss, Anger, vascular problems, stress, headache, nausea, irritability, and irreversible hearing loss. Hearing loss in industrial environments is made due to the prolonged exposure with the high level sound pressures and considered as the agent of one third of occupational diseases in Europe. One of the most current and important industries with high level sound pressures in Iran is oil and gas industry. Iran has a special status in terms of oil and gas resources in the region and world, so that it is considered as the fourth crude oil producer, fifth crude oil exporter, and third country having oil reserves. This industry provides the material and energy to other industries and can play a substantial role in economics of developing countries. Abadan oil refinery is largest refinery of Iran and one of three largest refineries in the world. This refinery has been located in Khuzestan province of Iran and occupational noise in mostly its units has exposed the employees to adverse health effects. The results of various studies performed on physical harmful agents, particularly noise, in the oil and gas industry and related companies indicate that noise exposure in some their units is higher than acceptable limit in some units. Given the special status of oil industries and the high volume of labor forces in these industrial units, the present study was aimed to evaluate the workplace noise in operational units of reservoirs and petroleum products transportation of Abadan oil refinery and investigate the impact of control measures on the noise exposure. Methods: This cross sectional and analytical study, was carried out in the operational units of tanks and petroleum products transportation including Crude oil pumping stations 1, 2, and 3, pus oil pumping station, MTBE, Control Center, NTA, KTA, mixing and fusion, fuel transportation, spherical reservoirs, and mazut unit. At the first, the basic information including locations of noise sources and operating conditions of equipment in the various units were collected for determining the noise pollution and identifying the noise productive resources. Then, the values of the sound pressure level were measured using sound level meter, model CEL 490, made by Casella company based on ISO 9612 standard. As well as, the sound level meter was calibrated by the calibrator, model CEL-110/1. In addition, the noise characteristics of the productive resources were determined by ISO 3745 standard. Based on ISO 9612 standard, the studied units were divided to equal squares with the dimensions of five and five meters using a regular network measurement pattern and the centers of these squares were specified as the measurement points. Given that the noise variations were lower than five dB, the values of the sound pressure level were measured at least three times in each point and their mean were calculated as the sound pressure level of each point. The least time of noise measurement in each point was fifteen seconds. To identify the main noise productive resources and dangerous areas with high sound pressure level, the measurement results were depicted in the form of a noise plan. The mean values of air temperature and relative humidity during the measurements were 38 degrees of centigrade and 64 percent, respectively. As well as, wind speed was slow. Give the aim of study, network A was selected as sound level measurement weighting scale and mean height of sound level meter from ground surface was nearly 1.55 ± 0.175 meters. After identifying the main noise productive sources in the units, control measures including were determined and implemented based on the type of the noise source. The used control solutions included lubrication of moving parts, repairs, improvement of pumps foundations, reduction of exposure time, and, use of personal protective equipment during exposure to the noise. Based on the type of the noise source, one or combination of control solutions were used. And measurements were carried out in controlled areas. Finally, after performing control measures, the re-measurement of sound exposure in similar situations was carried out in units. In final, the noise measurements were repeated again after performing the control measures based on the stated method. Results: In total, 11 units were investigated in this study. The results of environmental noise pollution measurement in the operational units of reservoirs and petroleum products transportation showed that NTA unit with the mean sound pressure level equal to 89.28 dB and spherical reservoir unit with the mean sound pressure level equal to 75.33 dB have the highest and lowest values of the noise pollution, respectively. Based on the results, of 523 measured stations in the present study, 115 stations were with a sound pressure level more than 85 dB, 373 stations with a sound pressure level from 65 to 85 dB, and 30 stations with a sound pressure level less than 65 Db. Of the total measured stations, 71.3 percent are in alert zone, 21.9 percent in risk zone, and 5.7 percent in safe area. NTA unit had the most number of the stations higher than 85 dB and KTA unit had the least number of the stations less than 85 dB. Of total stations with the sound pressure level higher than 85 dB, 19 percent was related to control center unit, 4.54 percent related to KTA unit, 9.37 percent related to crude oil pumping station 2, 27.5 percent related to crude oil pumping station 3, and 34 percent related crude oil pumping station 1. The results determined that the control measures decreased the mean sound pressure level of crude oil pumping station 1 by 2.39 dB, of control center unit by 1.7 dB, of pus oil pumping station and MTBE units by 0.89 dB, and of NTA by 0.08 dB. As well as, the results of the measurements indicated that the sound pressure level of other units did not significantly change. Conclusion: The results showed that the highest and lowest values of the sound pressure level were related to NTA unit and spherical reservoirs unit, respectively. The most inappropriate stations with the high noise pollution were related to NTA unit. This unit have a great importance among studied units because of the number of people exposed to noise and the value of noise pollution. Given the environmental measurement results, units with a mean sound pressure level higher than 85 dB require the corrective actions, particularly technical engineering measures and effective control strategies, for the continuous improvement. Based on the measurement results, 115 stations have the values of the sound pressure level more than 85 dB. If the engineering and administrative control measures are not implemented, the exposure time should be reduced. The results of the present study indicated that the implementation of the low-cost control methods and the repair and maintenance of the equipment and devices can decrease the noise exposure. In addition, these control measures increase the mean allowable time exposure. These results suggest that the appropriate control measures can cause the optimal use of the workers and professionals in different occupations. Refineries are one of the industries that most parts of it produce the noise pollution. As well as, because of the number of employees, exposure to a variety of harmful agents, and difficult environmental conditions, the control measures such as engineering solutions in oil and gas refineries should be given more attention. To reduce the noise exposure in the operational units of reservoirs and petroleum products transportation, the following control solutions are proposed. The maintenance, repairs, and proper lubrication of the machinery and equipment will reduce the unwanted noise production. It should be noted that the machinery maintenance and repairs not only are necessary for the noise control, but also increase the useful life of the machinery. Vibration also is one of the noise productive sources. Vibration can be controlled using the appropriate foundation, rubber layers, and etc. This solution will reduce the sound pressure level generated by the vibration. As well as, the appropriately choice of the machinery or equipment reduces the level of the unwanted noise. The selection of the machinery with the most consistent and with the lower levels of the undesired noise production due to higher technology are considered as key factors in the strategies to minimize the unwanted noise. Prohibiting or restricting the use of the noise productive equipment can significantly diminish the unwanted noise. In addition, given to 12-hour planning of the staff shift work and the mean value of the sound pressure level in the operational units, job rotation can be effective. Finally, the hearing protective equipment as the latest solution of the unwanted noise control can be applied. If this control measures are correctly implemented, those can greatly reduce the noise pollution and ensure the increase of the employees' health and productivity. © 2019 Iran University of Medical Sciences. All rights reserved.