PAPRa N100 Testing Guide (March 2024 Edition)
How we tested the PAPRa to arrive at claims of N95/N99 levels of protection
PAPRa Testing
Descriptions of the various tests and their results
Quick Synopsis
We came up with a series of tests to ensure that the PAPRa would be performant. Performant means:
When worn, the wearer received N99 levels of protection. This page describes how we did that testing in March of 2021 on both individual fan units and on a tester wearing the entire PAPRa.
The unit must maintain positive pressure under operating conditions. This pressure requirement supercedes past flow requirements for two reasons: 1, it is hard to measure flow accurately, and 2, if the wearer is able to breathe more than the flow of the device, even if the device meets some standard flow rate, then the device would not protect the wearer. As of October 2022, these devices to appear to exceed the 4 CFM flow requirement, and require that the potentiometer be set such that the pressure in the system exceeds that of the wearer’s inhalation. That previous 4 CFM requirement comes from Hooded PAPRs require a flow of 6 CFM; since the PAPRa is designed to provide airflow for a half facepiece, the flow requirement is 4 CFM, or 113.27 L/min[1].
WARNING
Before you wear a PAPRa in any kind of potentially hazardous situation, it is critical that you test it to ensure that the unit is performing at an adequate level. We have personally worn these units for many hours and tested these units to ensure an N99 level of performance, but we cannot guarantee that the units you make will perform at the same levels. We provide no warranty, implicit or explicit, that any such units will provide protection. Please make sure to test your units accordingly and to your own level of comfort and in compliance with whatever local regulations require.
1. Interpretation of Inhalation Airflow Measurements for Respirator Design and Testing. L.L. Janssen, N.J. Anderson, P.E. Cassidy, R.A. Weber, and T.J. Nelson. Journal of the International Society for Respiratory Protection, Vol. 22, pp. 122-141 referencing Burgess WA, Reist PC (1969) Supply rates for powered air purifying respirators. Am Ind Hyg Assoc J 30:1-6.
PAPRa N95 Testing Guide (March 2021 Edition)
How we tested the PAPRa to arrive at claims of N95/N99 levels of protection
PAPRa Pressure Testing (October 2022)
How we tested the PAPRa to determine the amount of air flow it produces
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Last modified November 3, 2022: moving around the testing guide to just have flow and N95 testing guides (643e51f)