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.
We want all the hazardous contaminants to be blocked by the filter media with a mask or respirator. To ensure that, we 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。
宽松贴合型 PAPR 适合有胡须的人配戴，是这样吗？
Loose-fitting PAPRs are designed not to rely on a tight seal to ensure protection, instead, they rely on positive pressure generated by the PAPR in the breathing zone to block outside contaminants from getting through the gaps in the loose-fitting partial seal while the PAPR sucks air via a filter.
但为了能按这个方法正确的工作，鼓风机需要产生可供佩戴者呼吸的所有气量，如果这种 PAPR 能够实现这一点，那么是的，它确实适用于有胡须的或者有面部毛发的佩戴者。
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.
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。
Therefore, the PAPR needs to be designed in such a way that it generates a flow more than what the wearer can breathe plus the flow leaked over the loose-fitting interface.
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。
This is because during a negative pressure condition, when the inhaled air outruns the air delivered from the blower, a tight-fitting mask will let in much less outside air compared with a partially sealed loose-fitting covering.
Typically, a tight-fitting mask is made of soft silicone rubber that contacts 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.
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 and far better than a non-powered respirator of typically only between 100 to 500. 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.
So to answer the question, yes, a tight-fitting PAPR can be used with a light-beard person similarly to a loose-fitting PAPR, provided the facial cushion is well designed, the beard is reasonably short, the flow generation is powerful enough, and most importantly, the ability to ensure positive pressure inside the mask.
Having said that, the EU highest class TH3 for loose-fitting is not ideal for work conditions that require a minimum protection factor of 1000 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 for a protection factor of up to 500.
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。
- You should be clean-shaven whenever you can, even if you wear a PAPR.
- If you insist on keeping your beard, you must use a PAPR and make sure:
- Trim your beard to a minimum.
- Use for work 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 Aimwell® AYO™ WX.
