铸造作业粉尘的不同连续采样方法检测结果若干关系探讨

[目的]探讨铸造行业作业场所粉尘连续性采样中，个体采样和区域采样两种测定结果间的相关关系和相关程度，以及季节因素和不同作业场所对采样结果的影响。[方法]选择3家工厂的铸造车间作为采样现场，分别在各工种选取36、23、14人进行个体全工作班随身采样，并同时进行工作区域定点采样。冬、夏两季每季重复进行3次。以重量法测定粉尘总量并计算出粉尘浓度。对各工厂夏冬两季各工种以及各工作区域的空气粉尘平均浓度，进行工种浓度和区域浓度、季节和工厂之间的比较分析。[结果]工种浓度各厂都有从造型各工种到开箱各工种浓度渐高的趋势排列，其中两个厂的浓度排列趋势有极显著性的统计学意义，F值分别为9．30和16．36，P〈0．01。区域采样所得的区域浓度与相应的工人个体采样所得的工种浓度或缺乏显著性相关，或未见显著性差别。冬季各工种的个体样品和区域样品所测得的粉尘平均浓度普遍高于夏季时的相应样品，其中造型（t=4．56）、制芯（t=4．34）、开箱冷却（t=5．88）、开箱打磨（t=3．49）、以及铸造车间行车（t=2．97）工种和制芯间（t=2．79）区域的季节差异表现出统计上的显著性。3个厂之间，某些类似工种个体接触和类似工作区域的空气粉尘平均浓度的差异有极显著性，有色金属铸造厂的浓度都是最低。[结论]在大中型的黑色金属铸造生产场所，区域采样不能很好地代表或替代个体采样以反映作业者实际的粉尘接触浓度。在有色金属铸造中，如考虑到含二氧化硅砂的国家卫生标准值，区域采样还是不能代表作业者实际的粉尘接触浓度是否在国家标准以下。季节因素（实际上是工作场所的自然通风因素）在决定实际接触粉尘浓度方面，具有至关重要的作用。在中等规模生产标准产品的铸铁工艺过程在造型工段的粉尘对工人危害最大；大规模的铸钢工艺生产在熔炼和开箱清砂工段的粉尘对工人危害最大。

The Study on the Some Relationships of the Measurements from Different Continuing Shift Dust Samplings in the Workshops of Foundry

[ Objective] To ascertain the correlation among the measurements by the methods of continuing shift dust sampling,personal sampling and field sampling,in the workshops of foundry,and the impact on the measurements from the factors of seasons and different workshops. [ Methods] The foundry workshops of 3 factories were selected and 36,23,and 14 workers were chosen respectively from the 3 factories as the subjects to conduct the shift personal dust sampling and area dust sampling at the same time. The sampling was conducted 3 times repeatedly in both seasons of winter and summer. The dust in total was measured by the weighing method and the dust concentrations were calculated. The statistic analysis was made for the relationships of the different dust concentrations of several personal job titles and relevant work fields,of different seasons,and of different factories. [Results] The trends of rising dust concentration were shown from the job titles of molding to the job titles of box opening in every factory,and the trends in two foundries had the statistical significance,F = 9.30 and 16.36,P < 0.01. No significant correlation or difference was seen between the area dust concentrations and their relevant personal job title dust concentrations. Almost all the area dust concentrations and the personal job title dust concentrations sampling in winter were higher than that sampling in summer, and the job titles of molding( t = 4.56),core making( t = 4.34),cooling( t = 5.88),grinding( t = 3.49),and crane in the foundry workshops( t = 2.97) and the area of core making workshop(t = 2.79) were shown the statistical significance. The average dust concentrations among some similar job title personal exposures and work sites were shown the significant difference,and the lowest in the nonferrous foundry. [ Conclusion] The area sampling can not represent or substitute the personal sampling to show the dust concentration actually exposed by the workers in the large- and middle-scale ferrous metal foundry. And it can also not reflect whether the dust concentration actually exposed by the workers is under the national standard in the nonferrous metals foundry,ifconsidering the national standard value with the sand containing silicon dioxide. The season factor(in actually,natural ventilation of workshop) is very important in determining actual dust-exposed concentration. The most severe dust hazard occurred in the molding job titles of the cast iron process of the middle-scale factory producing the standard products. And in the furnace,box opening,and sand cleanup job titles the most severe hazard occurred in the cast steel process of the large-scale factory.