Challenges in Predicting the Filtration Performance of a Novel Sewn Mask: Scale-up from Filter Holder to Mannequin Measurements
Challenges in Predicting the Filtration Performance of a Novel Sewn Mask: Scale-up from Filter Holder to Mannequin Measurements
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DOI：
10.4209/aaqr.200629
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发表时间：
2021
影响因子：
4
通讯作者：
Audrey J Dang;B. Kumfer;J. T. Bertroche;Jane Olson Glidden;Christopher R. Oxford;Udayabhanu M. Jammalamadaka;Mary Ruppert-Stroescu;A. Scott;J. Morris;C. Gan;Jesse Hu;Bradley King;David Dhanraj;Shruti Choudhary;P. Biswas;R. Axelbaum;K. Meacham;Brett Williams
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作者：
Audrey J Dang;B. Kumfer;J. T. Bertroche;Jane Olson Glidden;Christopher R. Oxford;Udayabhanu M. Jammalamadaka;Mary Ruppert-Stroescu;A. Scott;J. Morris;C. Gan;Jesse Hu;Bradley King;David Dhanraj;Shruti Choudhary;P. Biswas;R. Axelbaum;K. Meacham;Brett Williams
为应对COVID-19大流行期间的短缺，新型过滤式面罩（ffr）的设计和材料得到了推广。由于过滤效率取决于颗粒直径和空气面速度，因此材料过滤或原型拟合数据的相关性取决于测试条件。我们研究了在一定的面速度范围内表征过滤器支架中的材料是否能够精确预测新型缝制口罩设计的过滤性能。虽然较大的颗粒（>500 nm）与吸入接触呼吸排放物更相关，但我们将该口罩和N95 FFR（作为对照）与N95测试方法中更相似的较小颗粒进行了比较。我们的口罩（用硅胶密封在人体模型头上）由灭菌膜缝制而成，过滤了85±1%的136 nm颗粒（NaCl, 85 L min-1），并通过了6名志愿者中的4名的定量匹配测试，代表了介于外科口罩和N95 FFR之间的中间保护。过滤支架材料测量值将缝制口罩的过滤效率高估了8.2% (95% CI 7.4-9.1%)（136或200 nm）。虽然在过滤器支架中测试扁平材料可以在材料之间进行比较，但过滤性能不能精确地从过滤器支架扩展到人体模型测试。如果临时设计打算替代商业外科口罩或FFR，则在相关条件下测试完整原型至关重要。
ABSTRACT Novel designs and materials for filtering face-piece respirators (FFRs) have been disseminated in response to shortages during the COVID-19 pandemic. Since filtration efficiency depends on particle diameter and air face velocity, the relevance of material filtration or prototype fit data depends on test conditions. We investigate whether characterizing a material in a filter holder at a range of face velocities enabled precise prediction of the filtration performance of a novel sewn mask design. While larger particles (>500 nm) are more relevant for inhalation exposure to respiratory emissions, we compare this mask and a N95 FFR (as a control) with smaller particles more similar to those in the N95 test method. Sewn from sterilization wrap, our mask (sealed to a mannequin head with silicone) filters 85 ± 1% of 136 nm particles (NaCl, 85 L min-1) and passes quantitative fit tests for 4 of 6 volunteers, representing intermediate protection between a surgical mask and N95 FFR. Filter holder material measurements overpredict the sewn mask’s filtration efficiency by 8.2% (95% CI 7.4-9.1%) (136 or 200 nm). While testing flat material in a filter holder enables comparison between materials, filtration performance does not precisely scale-up from filter holder to mannequin tests. Testing full prototypes at relevant conditions is crucial if an improvised design is intended as a substitute for a commercial surgical mask or FFR.