BunnyPAPR Needs Your Help

BunnyPAPR Needs Your Help  

Noble Member

Many of you have been following my BunnyPAPR from its start to current, fully functional design. It is already helping people around the world, but getting it distributed in higher volume runs into the problem of regulatory red-tape.

There is a piece of red tape that blocks the way. BunnyPAPR fits neither of the previously defined classes of PAPR's (tight-fit and loose-fit) Those traditional PAPR's require four to five times more airflow to work properly and NIOSH's current testing criteria specify minimum air flow rates that are appropriate to those traditional PAPR's.

BunnyPAPR is a completely different type of PAPR. I call it "Sealed Fit Compliant Volume

The design of BunnyPAPR needs 20 to 20 liters/minutes instead of tight fit's 115 LPM or loose fit's 170 LPM! 

That is a huge difference.

So, if we submit BunnyPAPR for approval, it may get outright rejected because current rules only specify the large flow minimums that are totally inappropriate for the BunnyPAPR.

There is currently an open commentary period on new COVID-19 Response PAPR regulation. It would be very helpful to have additional comments supporting a new type of PAPR (Sealed Fit Compliant Volume) and its lower flow rate minimum of 25 liters per minute.

The commentary page link and what I wrote as my comment follow. 

Thanks in advance for your help.



There is a new design of COVID-19 response PAPR with a compliant respiratory reserve bag that that does not fit into either of the traditional tight fit or loose fit classifications.

This new type of PAPR was specifically designed to meet needs of healthcare worker facing the COVID-19 threat and is far more readily built and deployed than traditional PAPRs.

The required flow rate for our new class of PAPR is only 25 to 30 liters per minute to achieve adequate CO2 clearance and isolation. This four fold reduction in airflow and power requirements is a substantial leap forward for devices intended for the healthcare environment.

I refer to the new type of PAPR as "Sealed Fit Compliant Volume" PAPR

Section § 84.175 specifies rates that are inapplicable to Sealed Fit Compliant Volume PAPRs

115 liters per minute for tight-fitting facepieces
170 liters per minute for loose-fitting hoods and helmets

Both of the traditional classes are FIXED volume devices lacking a compliant respiratory reserve bag.

Addition of a respiratory reserve bag DRAMATICALLY reduces total flow requirements. The air volume in the compliant bag supplies air when peak inspiration exceeds fan/filter flow. So fan/filter flow no longer needs to exceed respiratory minute ventilation. One way expiratory valves prevent reverse flow into PAPR.

Addition to Section § 84.175 of a separate flow requirement for "Sealed Fit Compliant Volume" PAPR would further the public good. For example...

25 liters per minute for Sealed Fit Compliant Volume PAPRS.

Additional information about a Sealed Fit Compliant Volume PAPR can be found at

Guy Kuo, MD

Posted : 23/05/2020 8:09 pm
Noble Member

Two reports of the loop fracturing like this without apparent excess abuse....


Loop has been greatly strengthened  and pivot mechanism removed in version b7.


Posted : 26/05/2020 10:24 pm
Noble Member

Ack! Wrong thread.


Posted : 26/05/2020 11:20 pm

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