对胡须的常规要求

Powered Air Purifying Respirator (PAPR) for beards

这里的问题是关于佩戴口罩或呼吸器时的呼吸防护问题。

这里，“呼吸器”可以分为 空气净化呼吸器（APR） 和 动力空气净化呼吸器（PAPR）。

就 PAPR 而言，有紧密贴合型PAPR 和宽松贴合型PAPR两种。

这里，“紧密贴合”是指呼吸器和皮肤之间的面部紧密密封，设计目的是为了无泄漏； “宽松贴合”是指呼吸器和皮肤之间有意设计的非严密密封，以放宽贴合要求，允许少量泄漏。

典型的紧密贴合呼吸器具有弹性脸衬，典型的宽松贴合呼吸器包括头盔、护脸罩或头罩。

Except for Loose-fitting PAPRs, clean-shaven is the common requirement for wearing a tight-fitting respirator, especially a paper mask or an APR.

原因很简单：

you want all the hazardous contaminants to be blocked by the filter media with the mask or respirator. To ensure that, you want to ensure no gap between the mask/respirator and your facial skin. With facial hair, such as a beard, your mask or the respirator cushion will contact your beard first instead of your skin, leaving a gap for the contaminants to bypass the filter media to be sucked under negative pressure in the mask during inhalation.

所以，是的，如使用负压面罩或呼吸器（APR），您必须将胡须刮干净才能达到预期的保护，这是毫无疑问的。

然而，这里可能存在误解，认为宽松贴合型 PAPR 完全适用于有胡须的佩戴者，而不考虑其局限性。事实上，其适用程度是很受条件限制的，并且在应用中可能会受多个因素的制约，例如：

• 面部毛发有多长以及其分布的位置？
• 所使用的宽松贴合型PAPR 的鼓风能力有多强？
• 如何控制气流？内置电池电量低时流量会变少吗？
• 体力劳动对您呼吸的负荷有多大？
• 污染物的浓度有多大？
• 污染物的最大暴露限值是多少？

Most of these factors are related to the single most essential characteristic of PAPRs: Positive Pressure in the mask/breathing zone. As long as positive pressure is maintained all the time, there will be no leak issue from facial hair, as the air tends to be pushed out of the mask instead of being sucked in.

所以关键问题是如何始终保持正压。

理论上，只要PAPR中鼓风机产生的气流不小于吸入流量，就可以维持正压。但实际上，对于宽松的头盔、护脸罩或头罩，泄漏路径会多变，因此并非所有来自鼓风机的气流都能到达呼吸区域。有些气流可能会在到达呼吸区之前就泄漏出去了。

因此，PAPR 的设计应使其产生的流量大于佩戴者可吸入的流量再加上经宽松贴合部位可能泄漏的流量。

PAPR能产生多少气流取决于PAPR的鼓风能力；然而，吸入的空气流量取决于您工作时需要多用力呼吸。

可现实情况是，PAPR 可以产生的最大流量是有限的，并且当使用一定时间电池电量变低时，其流量也会低于初始水平。

此外，大多数宽松贴合型PAPR提供的是恒定的流量。这样流量越高，要求的电池容量也会相应增加，这会使电池变得更大、更重，因而降低可穿戴性并增加成本。

On the other hand, if your job is highly physical and causes heavy breathing, your inhaled air could outrun what the blower can deliver.

另一方面，如果您的工作是高强度体力劳动会使你深度用力呼吸，您吸入的气量可能会超过鼓风机所能输出的气量。 另一个需要考虑的重要因素是做某些工作时对 PAPR 的保护系数要求。污染物的浓度和最大暴露限值将决定 PAPR 的最小防护系数。通常，宽松贴合型 PAPR 的防护系数比紧密贴合 PAPR的 低。当污染物暴露限值要求 PAPR 具有高防护系数时，宽松的 PAPR 可能就不适合了，无论您是否有胡须。

因此，为了确保所选宽松贴合型PAPR 适合某种作业，特别是对有胡须的人，需要根据具体情况进行仔细评估。  

紧密贴合型 PAPR 可以用于有胡须的人吗？

当鼓风机的流量、所使用的过滤器和系统泄漏量相当时，紧密贴合型 PAPR通常比宽松贴合型PAPR具有更高的防护系数。

紧密贴合型 PAPR 在相对较小的区域内具有较好的密封性，而宽松贴合型 PAPR 在相当大的区域内只具有部分密封性，这使得紧密贴合型 PAPA 的泄漏比宽松贴合型 PAPR 的泄漏要少得多，因此紧密贴合型PAPR具有更高的防护系数。

Typically, a tight-fitting mask is made of soft silicone rubber contacting the front of the face, and it is elastic enough to adapt to the contour of the face to achieve a good seal. In contrast, a loose-fitting covering typically uses elasticized fabric at the contact interface, and it may cover a much larger area, such as the head, the face, and the neck, than only the front of the face.

A tight-fitting PAPR has a much better seal over a relatively small area, whereas a loose-fitting PAPR has a partial seal over a rather large area, resulting in the leak from tight-fitting PAPAs being much less than from the loose-fitting PAPRs, hence the tight-fitting PAPRs have higher protection factor.

Now, if the beard is short enough such that the silicone cushion from the tight-fitting PAPR can still achieve a better seal than loose-fitting PAPRs, there is no reason why the tight-fitting PAPR can’t work as effectively if not better than a loose-fitting PAPR, given the loose-fitting covering has more leaks.

As an example, AYO WX HFM Standard Half-Face Mask PAPR System, which has a well-designed silicone facial cushion, was tested on a light-beard person achieving an average PortaCount fit factor over 2000 when powered on, similar to a clean-shave person under the same test conditions. The key reasons AYO WX PAPR can achieve this are due to its powerful peak flow of over 200 L/min, which is similar to most loose-fitting PAPRs, and also due to its positive pressure ensured by the responsive flow control that can quickly accelerate the blower output anytime when the inhalation increases.

所以回到先前的问题，是的，与宽松贴合型PAPR类似，紧密贴合型PAPR也可以适用于短胡须的人使用，但前提是要有好的面部脸衬设计，胡须要足够短，气流要足够强，最重要的是确保面罩内部正压的能力。

Having said that, loose-fitting PAPRs are not suitable for high-exertion work with heavy breathing, as once the breathing outruns the blower, negative pressure will be created in the breathing zone, causing leaks to contaminants. In this situation, a tight-fitting PAPR is more appropriate, and loose-fitting PAPRs are normally limited to light to moderate workloads.

总而言之，下面是我们对有胡须人士的建议

• 佩戴负压呼吸器时，必须将胡须刮干净。
• 即使您佩戴 PAPR，也应尽可能将胡子刮干净。
• 如果您必须保留胡须，则必须使用 PAPR 并确保：
• 为了你的肺和你所爱的人的缘故，把胡须修剪到最少。
• Use for works with light to moderate exertion.
• 使用 PAPR 前请将电池充满电。
• 避免使用堵塞的过滤器——要经常更换过滤芯。
• 尽量选用可以产生较大气流的 PAPR。
• 尽量选用具有较小泄漏和设计优良的弹性脸衬的 PAPR。
• Try to use a PAPR with powerful and intelligent breath-responsive flow control like an AYO WX.