Abstract

Surgical N95 filtering facepiece respirators (surgical N95 FFRs) are National Institute for Occupational Safety and Health-approved N95 filtering facepiece respirators (N95 FFRs) cleared by the Food and Drug Administration for resistance to liquid penetration and flammability. A recent study showed that several N95 FFR models performed as well as surgical N95 FFRs in synthetic blood penetration tests that evaluate resistance to penetration by horizontal projection. This aspect, in addition to the influence of other factors on liquid penetration, are not well studied. To address this issue, the effect of liquid volume (1 mL and 2 mL), spray velocity (450 cm/sec and 635 cm/sec), and liquid composition (synthetic blood and diluted synthetic blood) were evaluated. Four types of common protective devices were studied: N95 FFRs, surgical N95 FFRs, surgical masks, and powered air-purifying respirator (PAPR) hoods. For each protective device type, five models were analyzed using a protocol based on the F1862 ASTM International (2017 ASTM International . 2017. Standard test method for resistance of medical face masks to penetration by synthetic blood (horizontal projection of fixed volume at a known velocity). (ASTM F1862/F1862M-17). West Conshohocken (PA): ASTM International. [Google Scholar]) test method. Reduced liquid volume had a significant effect in only 3 of 20 models. Increased velocity had significantly greater penetration in 9 of 20 models. Diluted synthetic blood had significantly more penetration in 8 of 20 models. This last result was not expected because, in hydrostatic tests, surface tension of the diluted blood would be expected to reduce penetrability; however, across all models tested, data showed that the diluted spray was more penetrable. The study results suggest that fluid composition may be as important as velocity when considering liquid spray penetration. Furthermore, the penetrability of a spray may be inversely related to the penetrability through direct hydrostatic contact.

 抽象的

外科 N95 过滤式面罩呼吸器（外科 N95 FFR）是美国国家职业安全与健康研究所批准的 N95 过滤式面罩呼吸器（N95 FFR），并经美国食品和药物管理局批准，具有抗液体渗透性和可燃性。最近的一项研究表明，在通过水平投影评估渗透阻力的合成血液渗透测试中，几种 N95 FFR 模型的表现与外科 N95 FFR 一样。这方面，除了其他因素对液体渗透的影响外，还没有得到很好的研究。为了解决这个问题，评估了液体体积（1 mL 和 2 mL）、喷雾速度（450 cm/sec 和 635 cm/sec）和液体成分（合成血液和稀释的合成血液）的影响。研究了四种常见防护设备：N95 FFR、外科 N95 FFR、外科口罩和电动空气净化呼吸器 (PAPR) 头罩。对于每种保护装置类型，使用基于 F1862 ASTM International ( 2017美国材料试验协会 (ASTM) 国际。 2017年。医用口罩抵抗合成血液渗透的标准测试方法（以已知速度进行固定体积的水平投影）。 (ASTM F1862/F1862M-17)。西康舍霍肯 (PA) ： ASTM 国际。 [谷歌学术] ）测试方法。减少液体量仅对 20 个型号中的 3 个产生显着影响。在 20 个模型中，有 9 个模型的速度提高后渗透力显着提高。稀释的合成血液在 20 个模型中的 8 个中具有显着更高的渗透性。 最后一个结果是出乎意料的，因为在水压测试中，稀释血液的表面张力预计会降低渗透性；然而，在所有测试的模型中，数据显示稀释后的喷雾更具渗透性。研究结果表明，在考虑液体喷雾渗透时，流体成分可能与速度一样重要。此外，喷雾的渗透性可能与通过直接静水压接触的渗透性成反比。