天津某大型汽车整车制造焊装车间噪声测量的不确定度评定

Uncertainty evaluation of noise measurement in welding workshop of a large automobile manufacturing plant in Tianjin

目的噪声是汽车制造企业主要的职业病危害因素。通过对天津某大型汽车整车制造焊装车间噪声测量的不确定度评定,阐述不确定度的来源、定量计算、评定方法和测量结果报告方式。方法根据GBZ/T 189.8—2007《工作场所物理因素测量第8部分:噪声》、GBZ 2.2—2007《工作场所有害因素职业接触限值第2部分:物理因素》、GB/T 21230—2014《声学职业噪声暴露的测定工程法》,于2022年6月—2023年2月,选取该焊装车间上件操作、装配操作和修模操作3个岗位中有代表性的30名作业人员进行噪声测量。使用防爆型个体噪声剂量计,制定合理测量计划,读取并记录3个岗位作业人员的A计权等效连续声压级(L_(p,A,eq T,n)),计算每个岗位A计权8 h暴露声级(L_(AE,8 h)),进行不确定度评定。结果计算可得上件、装配、修模操作岗位LAE,8 h分别为83.8、84.6、80.5 dB(A),扩展不确定度分别为3.3、3.6、3.3 dB(A)(k=1.65)。上件、装配岗位计算得到的LAE,8 h低于接触限值[85 dB(A)],但可能(置信水平90%)包含接触限值,上件和装配岗位部分作业人员的L_(p,A,eq T,n)不符合GBZ 2.2—2007的噪声职业接触限值要求。结论噪声不确定度评定表征了噪声测量结果的分散性和可疑程度,不确定度主要来源为测量操作。建议保持对噪声控制设施的维护保养和更新,加强佩带护耳器现场管理,落实相关健康监护和管理制度。

Objective Noise is the main occupational hazard factor in automobile manufacturing plants.Through the uncertainty evaluation of noise measurement in welding workshop of a large automobile manufacturing plant in Tianjin,the source of uncertainty,quantitative calculation,evaluation method and reporting methods of measurement results were expounded.Methods According to GBZ/T 189.8-2007"Measurement of Physical Factors in the Workplace Part 8:Noise",GBZ 2.2-2007"Occupational Exposure Limits for Hazardous Factors in the Workplace Part 2:Physical Factors"and GB/T 21230-2014"Engineering Method for Determination of Occupational Noise Exposure in Acoustics",from June 2022 to February 2023,the 30 representative operators from parts mounting position,assembly position and mold repair position in the welding workshop were selected for noise measurement.Using explosion-proof individual noise dosimeters,develop a reasonable measurement plan,read and record the A-weighted equivalent continuous sound pressure level(L_(p,A,eqT,n))of three positions operators,calculate the A-weighted 8-hour exposure sound level(L_(AE,8 h))for each positions,and conduct uncertainty evaluation.Results Calculation showed that LAE,8 h of parts mounting position,assembly position and mold repair position were 83.8,84.6,80.5 dB(A),with expanded uncertainty of 3.3,3.6,3.3 dB(A)(k=1.65).The calculated L_(AE,8h )of parts mounting position and assembly position was below the exposure limit of 85 dB(A)but could include 85 dB(A)(confidence level:90%).The L_(p,A,eqT,n)of part of the workers in parts mounting position and assembly position didn’t meet the occupational exposure limit requirements for noise in GBZ 2.2-2007.Conclusion The evaluation of noise uncertainty characterizes the dispersion and degree of suspicion of noise measurement results,with the main source of uncertainty being measurement operations.It is recommended to maintain and update noise control facilities,strengthen on-site management of wearing ear protectors as required,and implement relevant health monitoring and management systems.