Powered Air-Purifying Respirator

Basics

• The formal name is "CAPR" or Controlled-Air Purifying Respirator
• A Device Mainly Used as a filtered/safe air supply in enviroments where there IS oxygen, and the user can breath normally (as in lung function isn't impaired), but a chemical/biological/particulate hazard exists/is expected
• Is essentially a forced air filter, with a hose leading to a mask
• Typically is a belt with the power/controls/filter, then a tube to a mask/hood
• A Similar "box" can feed a Positive Pressure Personnel Suit , a type of hazmat suit for bio uses (ie doesn't protect against heat (like firefighting "bunker suits" , or from certain liquids and/or radiation like other Hazmat suits
• Many DIY devices are essentially adapted CPAP machines

Usage

• Hood and hose are discarded after each use - [1]
• PAPR and general PPE protocols - [2]
• Used in Biosaftey Levels 3 and 4 (Medical, Bioscience, etc)
• Also useful for welding with large amounts of flux in non well ventilated spaces etc

Industry Standards

Welding

• A Welding Helmet and Respirator System by Miller
• 3M's Speedglass line
• All these go for ~1000-3000 USD (Welding Helmet part makes up the most, but still is most likely overpriced
• They typically include the welding eye protection, the air system, a hardhat, a hood, and a system of all these being integrated, and "slidable"?

Medical/Biosaftey

• 3M's Medical/Generic Devices

Basic Design

Container

• Either a backpack, like in the video, or a 3d printed "shell"

Power Supply

• The associated electronics
• Preferabbly something swappable / Hot Swappable either (For Emergency need (ie we need something that "just works" NOW this may be a lesser need, even just throw a 9/12v battery in the backpack etc)
  • A OTS System such as RYOBI 18V etc
  • OSE System with the batteries in a 3d Printed shell with inserted metal contacts

Controlls

• Should be simple enough to use an arduino
• Indicators of flow and status MAY be needed to reach proper capability (if it fails you NEED to know if in a "Hot Zone")

Blower Fan

• Something with X M^3/H airflow (without filter) and Y M^3/H airflow (with filter)
• Either OTS or a 3d printed fan with ots motor, or fully open source

Filter Mount

• A Standard mount, and 3d Printed adapters for different cartriges

Filter

• Some sort of standard cartrige
• Contractor grade face mask cartriges should work for welding
• Due to the "END IS NEAR" supplies and the surplus military supplies, CBRN grade CAN be used, but is overkill and thus more expensive than need be in most applications
• Standard Biosaftey cartrige?

Hose Adapter

• Standard?

Face Mask

• Standard CPAP?

See Also

• COVID-19
• Ventilator
• Open Source Pressure Swing Absorbtion 99% Nitrogen/High Percentage Oxygen Device

Useful Links

• The Wikipedia Page on CPAP