[MakeUsersWant]

For me, the Narwall's main value proposition beyond a standard FFP2 respirator is a super tight seal. Smoke is probably the best proxy I can test that with.

Would you be open to a full refund if I order it and can still smell cigarette smoke?

[rattray]

Would a negative pressure test suffice? (See our website). Smoke may have a false negative, as odorants are many times smaller than the target challenge particles.

[MakeUsersWant]

Unfortunately not. There is a huge safety difference between a negative pressure test ("fit check" below) and a test with an actual aerosol ("qualitative fit test"). All of the FFP2 respirators I have checked pass one and fail the other. I am hoping the Narwallmask can fill this gap.

From https://associationofanaesthetists-publications.onlinelibrar...

Due to the associated time and costs, some health officials propose the elimination of fit testing and advocate that a fit check is sufficient in determining respirator fit [39]. The NIOSH conducted a study that demonstrated protection of N95/FFP2 masks improved from 67% without fit testing to 96% with fit testing [40]. Subsequently, NIOSH determined fit check alone to be insufficient and fit testing should be mandatory when selecting filtering facepiece respirators or elastomer half mask respirators.

Three studies that included 1111 Asians assessed the ability of fit check to detect leak determined by a quantitative fit test [36, 41, 42]. Average (range) sensitivity and specificity of the fit check to correctly detect leak were 26 (14–40)% and 79 (58–92)%, respectively, and consequent average (range) fit test pass rate following ‘successful’ fit check was 56 (34–73)%. Another study found the protection factor of filtering facepiece respirators increased from 3.3 to 20.5 when comparing the results of the entire test panel with those who had passed the fit test [32]. However, non‐fitted filtering facepiece respirators are still likely to provide greater protection than surgical masks, with a measured protection factor of 1.2 (Table 1) [32].

In summary, while fit check remains recommended before each use of any respirator to ensure fit on a day‐to‐day basis (Grade 1C evidence), we recommend not to use fit check as a substitute for fit testing to identify the size and shape of respirator that fits best (Grade 1B evidence).

[rattray]

Thank you, I hadn't seen this!

For what it's worth, I think we provide tools to perform more accurate fit checks than are possible with other masks, but of course I don't have data to back that up, and this is a situation that warrants caution.

You can perform a standard fit test (eg; with Bitrex) with a Narwall, by the way, or a home-jury-rigged one, like this customer did: https://cdn.shopify.com/s/files/1/0264/5311/4970/files/Tim-s...

The smoke check sounds like a great idea too, I just can't confirm that it will produce a true result for Narwall since we haven't specifically evaluated that methodology.

Even if we can't accept a full return because the mask has been tried on, we always offer partial refunds at least when a customer isn't satisfied for any reason, if that's any help.