儿童口罩技术规范过滤效率及通气阻力试验方法比对及建议

Comparison of Filtration Efficiency and Ventilation Resistance Test Methods in Technical Specifications for Children’s Masks and Suggestions

颗粒物过滤效率及通气阻力是GB/T 38880-2020《儿童口罩技术规范》中最重要的技术要求之一。该标准规定过滤效率及通气阻力测试条件为:“测试时将口罩展开并使用适当的夹具固定。”对同一样品,采用不同截面积的夹具进行上述两项测试的比对验证试验,发现在固定流量下,试验夹具的截面积对测试结果有显著影响。试验截面积越大,过滤效率越高,通气阻力越小;试验截面积越小,过滤效率越低,通气阻力越大。建议《儿童口罩技术规范》进一步修订优化,对过滤效率和通气阻力两项测试规定合理的试验截面积,或采用固定流速方法测试。

Particulate filtration efficiency and ventilation resistance are one of the most important technical requirements in GB/T 38880-2020,Technical specification of children mask.The standard stipulates that the test conditions for filtration efficiency and ventilation resistance are“expanding the mask during the test and fixing it with an appropriate fixture”.The comparison and verification tests of the above two tests were carried out on the same sample using fixtures with different cross-sectional areas.It was found that under a fixed flow rate,the cross-sectional area of the test fixture had a significant impact on the test results.The larger the test cross-sectional area,the higher the filtration efficiency,and the smaller the ventilation resistance;the smaller the test cross-sectional area,the lower the filtration efficiency,and the larger the ventilation resistance.It is recommended that the technical specification should be further revised.Specifically,a reasonable test cross-sectional area should be specified for the two tests of filtration efficiency and ventilation resistance,or a fixed flow rate method should be used for the test.