NEW METHODS FOR QUANTITATIVE RESPIRATOR FIT TESTING

核监管要求进行定量呼吸器适合性测试 原子能设施工人健康保护委员会， 以及职业安全和健康管理局为工人提供的 接触铅、丙烯腈、无机砷和焦炉排放物。 在常规技术中，邻苯二甲酸二-2-（乙基-己基）酯（DOP）已被用作合成邻苯二甲酸酯。 用作测试气溶胶，以及内部和外部的浓度 掩模已经通过测量的光度测定 DOP云的散射光强度。 然而，DOP 最近被认为是一种潜在的人类致癌物。 拟 连续流动凝结核计数器（CNC）适于 测试可更换滤芯的负压净化器。 此外， 将制定新的测试方案。 CNC扩大 亚微米大小的细颗粒进入光散射范围， 实际上，任何非危险的细颗粒云都可以用于拟合， 试验. 使用一种特殊的气溶胶静电计将被研究作为一个 可能更简单的测量方法。 在探索新的和 简单的配合测试技术，保护系数也将被测量为 由于呼吸器的性能是预期的， 取决于由拟合测试产生的粒度分布 设备或实际工业环境。 不存在任何方法 在以下情况下佩戴的一次性口罩， 硅石、煤或一般有害粉尘。 提出了一种惰性， 无毒的，超微米级的灰尘，如石灰石， 流化床的装置，并且对于几个尺寸的粉尘浓度 掩模内部和外部的范围可以通过使用 空气动力学粒度分析仪 使用市售 强调工具，以达到可以使用的技术 立即从实践者。 新的拟合测试方法将 通过测量工业环境中的呼吸器贴合度进行现场评估。

Quantitative respirator fit testing is required by the Nuclear Regulatory Commission for the health protection of workers in atomic installations, and by the Occupational Safety and Health Administration for workers exposed to lead, acrylonitrile, inorganic arsenic and coke oven emissions. In the conventional technique, di-2 (ethyl-hexyl) phthalate (DOP) has been used as the test aerosol, and the concentrations inside and outside the mask have been determined photometrically through measurements of the scattered light intensities from the DOP clouds. DOP, however, has recently been implicated as a potential human carcinogen. It is proposed that a continuous-flow condensation nuclei counter (CNC) be adapted for fit testing negative pressure respirators with replaceable cartridges. Also, a new testing protocol will be developed. The CNC enlarges submicrometer-sized, fine particles into the light scattering range, so virtually any non-hazardous cloud of fine particles can be used for fit testing. The use of a special aerosol electrometer will be studied as a potentially even simpler measurement method. While exploring new and simple fit testing techniques, protection factor will also be measured as a function of particle size since the performance of a respirator is expected to depend on the particle size distribution generated by the fit testing apparatus or the actual industrial environment. No method exists at present for fit testing disposable masks which are worn in the presence of silica, coal, or general nuisance dusts. It is proposed that an inert, nontoxic, supermicrometer-sized dust such as limestone be dispersed by means of a fluidized bed and that the dust concentration for several size ranges inside and outside the mask be determined through use of an aerodynamic particle size analyzer. The use of commercially available instruments is stressed in order to arrive at techniques that can be used immediately by the practitioner. The new fit test methods will be field-evaluated by measuring respirator fits in industrial environments.