4家现代大型水泥厂生产工人职业噪声暴露分析

目的 鉴别现代水泥生产企业中主要的噪声源及其分布,研究水泥厂中高噪声产生的原因及其对作业工人健康的影响.方法 对广西4家典型现代大型水泥厂进行噪声危害调查,根据GBZ/T 189.8-2007《工作场所物理因素测量第8部分:噪声》要求对噪声设备布局、噪声源和噪声强度进行调查、检测;根据GBZ 188-2007《职业健康监护技术规范》对接触噪声工人进行职业健康检查.结果 4家水泥厂在物料破碎、粉磨、回转窑等工人较长时间工作的区域噪声强度超过85 dB(A),13.2％工人存在纯音听力测试异常.水泥厂噪声源主要有:破碎机、粉磨机、风机和空气压缩机.其高噪声产生原因为:使用高噪声设备,设备设施维护欠佳,控制室、操作间和休息室缺少声学设计.结论 4家现代大型水泥企业工人暴露于高噪声工作环境,并对听力等健康产生不良影响;应切实加强现代大型水泥企业噪声污染的防范和治理,加强对接触噪声这一职业群体的健康监护.     

烟草卷包作业场所噪声治理效果评价

目的评价联合工房卷包作业场所噪声吸声降噪治理前后控制效果。方法对该卷包作业场所噪声治理前后噪声频谱、强度(A声级)定点进行测量、配对t检验分析。结果吸声降噪治理后卷包作业场所噪声强度均有所下降,其中以远离设备噪声源测量点位的控制效果最好。设备进行近距离操作岗位,治理后噪声强度平均降低了2.6 d B(A);离设备声源距离较远区域,治理后噪声强度平均降低了6.8 d B(A)。结论离声源较远区域较声源附近吸声降噪效果好,为实现保护工人健康的目的,仍须采取联合工房吸声降噪治理工程与岗位作业人员佩戴护耳器结合的综合措施。     

某涤纶长丝生产线作业场所噪声危害的调查分析

目的为了解涤纶长丝生产过程中产生的生产性噪声对作业工人健康的影响,对某石化公司新建的涤纶长丝生产线噪声暴露情况进行了检测调查,以探讨其噪声对工人健康的危害程度。方法采用作业场所噪声水平检测和作业工人个体噪声暴露水平检测的方法。结果纺丝工段作业场所噪声平均水平为(83.17±0.72)dB(A),符合国家职业卫生标准接触限值的要求;卷绕工段作业场所噪声平均水平为(90±2.80)dB(A),均超过职业卫生标准接触限值的要求。频谱分析为中低频宽带。8h等效声级结果显示:纺丝工噪声暴露平均暴露水平为(82.00±0.11)dB(A)。卷绕工噪声平均暴露水平为(85.73±0.17)dB(A)。8 h/d等效声级结果:纺丝工82.70 dB(A);卷绕工85.13 dB(A),作业分级为I级,轻度危害。结论该生产线在噪声控制方面取得明显效果。减少噪声接触时间和降低作业场所噪声水平,定期作业场所监测。加强职业健康监护,及时发现职业禁忌证,预防噪声暴露的累积效应对噪声作业工人健康的危害。     

生产性噪声的新标准

最近苏联卫生部批准的“作业场所噪声容许水平的卫生标准”(NO 3223-85),自1985年3月12日起执行。该文件体现了按作业种类规定噪声标准的原则。卫生标准中包括执行监督的必需资料和确定作业场所噪声分类、特征、容许水平、标准测量的总要求及主要预防措施。鉴于现代生产设施功率增加和设备大型化的发展趋势,对低频噪声的卫生学意义日益引起重视,因此标准的频程扩大包括31.5赫中心频率。噪声容许水平按作业活动类别及有关作业点和作     

某钢铁厂高炉系统工程噪声强度测定分析

现代钢铁企业噪声特点如何 ,采取了什么样的措施 ,危害程度怎样 ?为此 ,我们对某钢铁厂大高炉系统工程的噪声作业场所进行了调查。1　内容与方法1 1　内容　　本次调查了高炉系统工程的各噪声作业场所 ,包括控制室、隔音室、休息室 ,并对不同设备噪声源进行频谱测试 ,另对巡视工 ,佩带个体剂量仪器以记录等效连续Ａ声级。1 2　方法1 2 1　按规范[1] 要求作场布点、测试。1 2 2　测试仪器为江西红声器材厂生产的ＮＤ -2型精密级计和丹麦Ｂｒｕｅ 18Ｋｊａｒ公司生产 442 8型个体计量仪 ,仪器2　结果2 1　基本情况使用前均经过中国标准计量…     

深圳市石材加工行业工作场所噪声频谱特性分析

目的分析深圳市石材加工行业工作场所噪声频谱特性,为行业开展噪声治理与防控提供科学依据。方法采用立意抽样法,选取38家石材加工企业进行噪声声级检测和频谱测量,运用聚类分析对不同岗位的噪声频谱特性进行分析。结果石材加工行业14种工作岗位中10种岗位的等效声级平均值超过了85 dB(A),开孔岗位的场所噪声最大值可达104.4 dB(A)。聚类分析结果显示,定厚、吹吸风干和开孔岗位的噪声频谱特征相似,在中低频和高频均有较高噪声声级。倒角、仿形、抛光、桥切、切边、干磨、手扶磨和水磨操作岗位的噪声频谱特征相似,以高频噪声为主。机器磨边、绳锯和水刀切割操作岗位的噪声频谱特征相似,噪声声级较小,均低于80 dB(A)。结论石材加工行业的噪声危害程度重,应依据频谱特性采取有效的工程控制措施和听力保护措施。     

中小化工企业中低频噪声听力防护调查

目的了解中小化工企业中低频噪声听力防护情况,并且分析在中低频噪声的防护效果。方法测量广东省12家中小化工企业工作场所中职业性噪声强度和频谱,对接触噪声的114名工人和对照组108名工人进行了纯音听力检查,结合现场噪声监测结果,分析工人听力损伤特点。结果调查工作场所中工人接触噪声主频率为中低频稳态噪声,噪声强度为70.6～96.2dB(A),观察组与对照组1kHz以上各频段听力损失均值差异均有统计学意义(F=9.1,P0.01),但是1kHz以下频率听力损失均值差异均无统计学意义。结论中低频职业噪声对接触者听力产生危害,对于1kHz频率以下的低频噪声危害应当尽快制定防护措施。     

某高尔夫球杆生产企业噪声危害现状调查

采用SV971型噪声频谱分析仪测量某高尔夫球杆生产企业工作场所噪声声级，依据国家标准评价是否超标并评估噪声作业级别。结果显示，共检测107个点，每周40h等效噪声声级79.2?103.2dB(A)，94个点≥85dB(A)，占87.9%；其中D栋生产单元检测点均≥85dB(A)；噪声危害主要集中在I级轻度危害(36.4%)和III级重度危害(35%)。提示该高尔夫球杆生产企业的噪声危害严重，存在较高职业健康风险；打磨岗位需重点防控。     

远洋测量船噪声暴露评估及作业人员听力保护建议

目的对远洋测量船噪声暴露情况进行现场测量及评估,对噪声场所作业人员听力进行测试分析,并提出听力保护建议。方法选用AWA 6218B型噪声统计分析仪及BK 2250手持式分析仪分别对A型、B型远洋测量船不同区域噪声进行测试评估。采用OR-BITER 922型听力计对噪声作业场所部分人员进行纯音听力测试。结果远洋测量船主、辅机舱存在危害较大的强噪声,其余各测点噪声值均符合GJB 4000-2000《舰船通用规范》要求。听力测试结果显示,随着工作年限的增加,作业人员高频听损、语频听损的发生率有所升高。结论远洋测量船主、辅机舱存在着危害较大的强噪声,部分作业人员听力损伤;相关部门应重视做好噪声场所作业人员的听力保护工作。     

某石油化工企业生产性噪声的调查及治理评价

目的对某石油化工企业生产性噪声进行调查,并对已采取的噪声治理措施进行技术评价.方法测量该企业噪声源的A计权声级、频谱特性和岗位噪声暴露状况,计算等效连续A声级.结果该企业生产装置中约有空气动力性噪声、机械性噪声和电磁性噪声等声源2 000个,其主要声源频谱以中高频为主,属宽频带噪声;在操作岗位噪声中,装置的总控室、控制室、操作室等室内噪声超过75 dB(A)的占8%,生产装置的噪声超过85 dB(A)的达48%,LAeq＞91 dB 的占13%.结论该企业的噪声治理措施中存在设计不合理或不够完善的地方.     

Annoyance and effects on work from environmental noise at school

The aim of this study is to investigate how students rate the annoyance and effects of noise in their working environment. 216 students, between the ages 13-15 years, and 12 teachers took part in this study. Sound level measurements were made for 20 minutes in the middle of a lesson for each class. On the measurement occasion the students were seated in a class room working on mathematics. Immediately after the sound level measurement, the students and the teachers filled in a questionnaire. The correlation between sound level and perceived annoyance and rated effect of noise on the students' schoolwork was poor. The correlation between the annoyance and rated effect of noise on the students' schoolwork was significant. Equivalent sound levels during mathematics lessons were 58-69 dB(A). Even though the sound levels were relatively high the students claimed that they were just moderately annoyed. More than 1/3 of the students claimed that the existing sound environment obstructed their work. No difference was found between boys and girls in rated annoyance and rated effect on their work. The younger students were more annoyed than the older ones. The participants claimed that chatter in the class room and scraping sounds from tables and chairs were the most annoying sound sources. The teachers shared this opinion. The concurrency between the students' rating of their annoyance and the teachers' rating of the students annoyance was remarkably low.     

Estimating occupant satisfaction of HVAC system noise using quality assessment index

Noise may be defined as any unwanted sound. Sound becomes noise when it is too loud, unexpected, uncontrolled, happens at the wrong time, contains unwanted pure tones or unpleasant. In addition to being annoying, loud noise can cause hearing loss, and, depending on other factors, can affect stress level, sleep patterns and heart rate. The primary object for determining subjective estimations of loudness is to present sounds to a sample of listeners under controlled conditions. In heating, ventilation and air conditioning (HVAC) systems only the ventilation fan industry (e.g., bathroom exhaust and sidewall propeller fans) uses loudness ratings. In order to find satisfaction, percent of exposure to noise is the valuable issue for the personnel who are working in these areas. The room criterion (RC) method has been defined by ANSI standard S12.2, which is based on measured levels of in HVAC systems noise in spaces and is used primarily as a diagnostic tool. The RC method consists of a family of criteria curves and a rating procedure. RC measures background noise in the building over the frequency range of 16-4000 Hz. This rating system requires determination of the mid-frequency average level and determining the perceived balance between high-frequency (HF) sound and low-frequency (LF) sound. The arithmetic average of the sound levels in the 500, 1000 and 2000 Hz octave bands is 44.6 dB; therefore, the RC 45 curve is selected as the reference for spectrum quality evaluation. The spectral deviation factors in the LF, medium-frequency sound and HF regions are 2.9, 7.5 and -2.3, respectively, giving a Quality Assessment Index (QAI) of 9.8. This concludes the QAI is useful in estimating an occupant's probable reaction when the system design does not produce optimum sound quality. Thus, a QAI between 5 and 10 dB represents a marginal situation in which acceptance by an occupant is questionable. However, when sound pressure levels in the 16 or 31.5 Hz octave bands exceed 65 dB, vibration in lightweight office construction is possible.     

Practical ranges of loudness levels of various types of environmental noise, including traffic noise, aircraft noise, and industrial noise

In environmental noise control one commonly employs the A-weighted sound level as an approximate measure of the effect of noise on people. A measure that is more closely related to direct human perception of noise is the loudness level. At constant A-weighted sound level, the loudness level of a noise signal varies considerably with the shape of the frequency spectrum of the noise signal. In particular the bandwidth of the spectrum has a large effect on the loudness level, due to the effect of critical bands in the human hearing system. The low-frequency content of the spectrum also has an effect on the loudness level. In this note the relation between loudness level and A-weighted sound level is analyzed for various environmental noise spectra, including spectra of traffic noise, aircraft noise, and industrial noise. From loudness levels calculated for these environmental noise spectra, diagrams are constructed that show the relation between loudness level, A-weighted sound level, and shape of the spectrum. The diagrams show that the upper limits of the loudness level for broadband environmental noise spectra are about 20 to 40 phon higher than the lower limits for narrowband spectra, which correspond to the loudness levels of pure tones. The diagrams are useful for assessing limitations and potential improvements of environmental noise control methods and policy based on A-weighted sound levels.     

声波除灰器低频噪声对豚鼠组织形态学与生理学指标的影响

在实验室条件下，观察了声波除灰器低频噪声对实验动物的影响。选用健康、耳廓反应灵敏的豚鼠３４只，随机分为４组，其中３组豚鼠暴露于主频为５０Ｈｚ的低频噪声环境，噪声强度分别为８５、９５、１０５ｄＢ（Ａ），每日接噪１．５小时，历时８周；另一组作对照。结果显示：接噪豚鼠的耳蜗及主要脏器的组织形态、听觉脑干电反应阈（ＡＢＲ）、血压和血象等无明显变化，尿香草扁桃酸（ＶＭＡ）含量较对照组明显增高（Ｐ＜０．０１）。     

Low frequency noise "pollution" interferes with performance

To study the possible interference of low frequency noise on performance and annoyance, subjects categorised as having a high- or low sensitivity to noise in general and low frequency noise in particular worked with different performance tasks in a noise environment with predominantly low frequency content or flat frequency content (reference noise), both at a level of 40 dBA. The effects were evaluated in terms of changes in performance and subjective reactions. The results showed that there was a larger improvement of response time over time, during work with a verbal grammatical reasoning task in the reference noise, as compared to the low frequency noise condition. The results further indicated that low frequency noise interfered with a proof-reading task by lowering the number of marks made per line read. The subjects reported a higher degree of annoyance and impaired working capacity when working under conditions of low frequency noise. The effects were more pronounced for subjects rated as high-sensitive to low frequency noise, while partly different results were obtained for subjects rated as high-sensitive to noise in general. The results suggest that the quality of work performance and perceived annoyance may be influenced by a continuous exposure to low frequency noise at commonly occurring noise levels. Subjects categorised as high-sensitive to low frequency noise may be at highest risk.     

Assessment and control design for steam vent noise in an oil refinery

Background: Noise is one of the most important harmful agents in work environment. Noise pollution in oil refinery industries is related to workers' health. This study aimed to determine the overall noise pollution of an oil refinery operation and its frequency analysis to determine the control plan for a vent noise in these industries. Methods: This experimental study performed in control unit of Tehran Oil Refinery in 2008. To determine the noise distributions, environmental noise measurements were carried out by lattice method according to basic information and technical process. The sound pressure level and frequency distribution was measured for each study sources subject separately was performed individually. According to the vent's specification, the measured steam noise characteristics reviewed and compared to the theoretical results of steam noise estimation. Eventually, a double expansion muffler was designed. Data analysis and graphical design were carried out using Excel software. Results: The results of environmental noise measurements indicated that the level of sound pressure was above the national permitted level (85 dB (A)). The Mean level of sound pressure of the studied steam jet was 90.3 dB (L). The results of noise frequency analysis for the steam vents showed that the dominant frequency was 4000 Hz. To obtain 17 dB noise reductions, a double chamber aluminum muffler with 500 mm length and 200 mm diameter consisting pipe drilled was designed. Conclusion: The characteristics of steam vent noise were separated from other sources, a double expansion muffler was designed using a new method based on the level of steam noise, and principle sound frequency, a double expansion muffler was designed.     

某居民小区噪声环境现状调查

目的 调查居民小区噪声环境现状，为有关部门进行小区规划建设和综合治理提供依据。方法 选择2个居民小区，全面测试环境噪声水平及小区动力设备和配套设施对居住环境的影响。结果 小区内部白天平均噪声水平在47-53[dB（A）]，夜间平均噪声水平在41-45[dB（A）]，临街居室窗外噪声水平高于小区内部噪声水平。暖通设备和地下车库通风口处局部噪声水平较高。结论 所调查小区的规划建设基本合理，总体可以满足环境噪声标准的要求。暖通设备层应设在地下2层，并进行隔声减振处理，地下车库通风口应远离居民楼，并进行消声处理。     

Evaluation of noise propagation characteristics of compressors in tehran oil refinery center and presenting control methods

Background: The adverse effects of noise are well known and noise problems due to industrialization of communities are increasing over the time. Oil industries due to the process and nature of production; contain many noise sources such as compressors, turbines, and pumps, which cause excessive noise exposure. The objective of this study was to evaluate the noise characteristics of compressors in Tehran Oil Refinery and study on visible control measures. Methods: To get to the appropriate control method, procedures such as basic theories, measuring sound parameters, frequency analysis, related diagrams and noise propagation schemes due to the measurement results, equivalent noise exposure level (L(eq(8h))) and exposure noise dose and technical specification of compressors are considered in this paper. Considering field and analytical re-sults, module enclosure with particular specifications (like absorbent layer, specific wall, window and door design etc.) is predicted to be the best control method. Results: Calculation results of multiple layer density of the enclosure (W = 16.5 kg/m(2)) and needed density for the dominant frequency of the source (W = 12 kg/m(2)) demonstrated that the designed enclosure satisfies the goal. Conclusion: Results of designing sandwich layers' module demonstrated that install-ing the designed enclosure causes 20 dB(A) reduction in total sound pres-sure level of the source's dominant frequency.     

A new approach to assess low frequency noise in the working environment

To assess high-level low frequency noise in the working environment, adverse extra-aural effects caused by the noise should be taken into account. The human body vibration induced by low frequency noise, 'noise-induced vibration', was measured on the body surface and the equal-acceleration level contours of the vibration were tentatively estimated. With these contours, we can predict the magnitude of noise-induced vibration at every measuring position on the body surface. This is helpful in relating the total dosage of low frequency noise with the physical symptoms caused by the noise. But some important points in the contours remain to be investigated and improved. When these points are dealt with, the equal-acceleration level contours will be useful for assessing high-level low frequency noise in the working environment from the standpoint of predicting the adverse extra-aural effects.     

Impulse noise and risk criteria

Impulse noise causes evidently more severe hearing loss than steady state noise. The additional effect of occupational impulse noise on hearing has been shown to be from 5 to 12 dB at 4 kHz audiometric frequency. Reported cases for compensated for hearing loss are prevalent in occupations where noise is impulsive. For impulse noise two measurement methods have been proposed: the peak level method and energy evaluation method. The applicability of the peak level method is difficult as even the recurrent impulses have different time and frequency characteristics. Various national risk criteria differ from international risk criteria. In France the maximum A-weighted peak level is 135 dB, and in the United Kingdom the C-weighted peak sound pressure is limited to 200 Pa (140 dB). This criterion of unweighted 200 Pa (140 dB) is used in European Union (EU) directive 86/188 and ISO 1999-1990 regardless of the number of impulses. The American Conference of Governmental Industrial Hygienists (ACGIH) has recommended that no exposure in excess of a C-weighted peak sound pressure level of 140 dB should be permitted. At work places these norms do not cause any practical consequences since the impulses seldom exceed 140 dB peak level. In several occupations the impulses are so rapid that they contribute only a minimal amount to the energy content of noise. These impulses can damage the inner ear even though they cause reduced awareness of the hazard of noise. Based to the present knowledge it is evident that there is the inadequacy of the equal energy principle in modelling the risk for hearing loss. The hearing protectors attenuate industrial impulse noise effectively due to the high frequency contents of impulses. Directive regarding the exposure of workers to the risks arising from noise requires that in risk assessment attention should be paid also to impulsive noise. So far there is no valid method to combine steady state and impulse noise. A statistical method for the measurements of industrial impulse noise is needed to get a preferably single number for risk assessment. There is an urgent task to develop risk assessment method and risk criteria for impulsive noise to meet the requirements of the upcoming European Union noise directive.