Air purifying respirators (APRs) filter contaminants to provide the wearer with safe, breathable air.  APRs use filters, specifically selected for the anticipated contaminants, to remove hazardous dusts or vapors.

APR’s come in positive and negative-pressure varieties.  Negative pressure respirators must be tight-fitting on the face of the wearer. In industrial settings, OSHA requires that the wearer be medically cleared and fit-tested for the particular make, model, and size of respirator they will be wearing.  Anything that interferes with the seal of the respirator (such as facial hair, and sometimes facial features),  renders tight-fitting respirators less effective.   US workers wearing respirators must be clean-shaven, having no more than 24-hours facial hair growth in the sealing area of the respirator according to Federal Standards.

Because the wearer’s lungs must exert extra effort to pull the air through the filters of a negative-pressure respirator, this can effect how well they are able to breathe.  As the APR’s filters clog with dust and other material, the amount of effort required to inhale can increase until breathing becomes difficult.   Medical conditions like asthma, high blood pressure, or lung injury can even make negative-pressure respirator use dangerous for some individuals, particularly during activities with increased physical exertion.

A Powered Air-Purifying Respirator or PAPR, takes some of that effort off the user’s lungs by using a motorized attachment to pull air through the filters, then supply it into the respirator by way of a hose system.   This keeps the pressure inside the respirator positive, which not only makes it easier to breathe, but helps protect users better even if they don’t quite have a perfect fit.  There isn’t any way for the contaminant to get sucked into the respirator as long as the mask remains pressurized.  “Tight-fitting” PAPR’s still require the user to have a correct fit and be clean shaven,  but “loose fitting” PAPR’s can work for the bearded among us by supplying air to a hood that goes around the user’s head and neck.  The pressure inside the hood remains positive, preventing any atmospheric contaminants from making it into the hood.

When selecting respiratory protection for children, the elderly, or anyone with breathing issues,  a positive-pressure respirator is going to provide a better level of protection and comfort.

That’s enough Safety Pro 101 for the day,  now let’s talk about the MIRA Safety MB-90 Powered Air Purifying Respirator:

The MB-90 is a battery-powered, motorized, detachable unit that will upgrade any standard gas mask or tight-fitting respirator that uses NATO 40mm filtering cartridges into a tight-fitting PAPR. Some commercial full-face respirators may require a hose adapter to make them compatible with the 40mm hose connector.

Using 8 standard AA batteries, the MB-90 will provide up to 12 hours of run time at a sustained airflow rate of 90 liters per minute.  While this flow rate is adequate for most private, non-industrial use,  keep in mind there are workplace safety standards that require a minimum of 115 liters/minute for tight-fitting PAPRs and 170 liters per minute for loose-fitting PAPR hoods.  If you are an employer, ensure you are researching the appropriate OSHA and NIOSH guidance before relying on any product required for daily workplace safety.

The MB-90 unit weighs 1.8lbs and straps to the user’s belt. It also comes with straps and its own bags for storage and carrying. It uses two 40mm CBRN filters that are attached directly to the motorized unit. The air supply hose connects directly to your respirator mask.

Having worked as an industrial safety professional for going on 25-years now, I have a just a few items of respiratory protection on hand.  Most of the commercial masks I have use proprietary cartridges and the connections were not compatible with the MB-90 hose fitting.  I did, however, have a Desert Storm-era Israeli gas mask that the MB-90 fit perfectly.   Testing the MB-90 on this mask with the standard Israeli filter cartridges, I found the air supply inside the mask quite adequate for comfort.


Out of curiosity, I tried the MB-90 on a loose-fitting PAPR hood as well,  it was maybe a little under-powered for that application.


Considering the price of most industrial units (typically $1000 or more),  and that the great majority of private users aren’t governed by OSHA standards,  the MB-90 provides reasonably-priced protection for the hobbyist, prepper, and other individuals looking to enhance their respiratory protection equipment.


I received this product as a courtesy from the manufacturer via Spotter Up so I could test it and give my honest feedback. I am not bound by any written, verbal, or implied contract to give this product a good review. All opinions are my own and are based off my personal experience with the product.

*The views and opinions expressed on this website are solely those of the original authors and contributors. These views and opinions do not necessarily represent those of Spotter Up Magazine, the administrative staff, and/or any/all contributors to this site.


By Michael Lake

Writer Michael Lake is a Benefactor Life Member of the National Rifle Association and has been actively involved in a variety shooting activities since 1989. In addition to being a certified range safety officer he holds several NRA instructor ratings and armorer certifications. He has received training from the US Army Marksmanship Unit, the US Marine Corps Rifle Team and some of the finest private training facilities in the nation. In 2013 Michael co-founded Adaptive Defense Concepts, a Northwest Ohio-based Training organization. currently a contractor for the Department of Energy managing safety for the National Homeland Security program in Eastern Idaho, an instructor for Badlands Tactical Training Center, and is an accomplished Freemason.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.