This design is an extension of https://3dprint.nih.gov/discover/3dpx-013599

The previous version was made from Tyvek and was designed to be partially disposable. This new version is made from fabric, but uses the same flat pattern and is offered as a more comfortable alternative to a P-100 mask. It is reusable and this respirator is intended for mass production. The features of this particular model are designed for those that work in law enforcement but would also be suitable for EMS, fire departments, healthcare workers and other first responders that require this level of protection.

Construction

The version pictured is sewn from coated Cordura 1050D - a dense, water repellant ballistic nylon that is extremely durable and used in tactical gear, protective gear for motorcyclists, winter apparel and backpacks. A key advantage of using high performance fabric in a respirator design is that the flexibility allows for a contoured and continuous fit (even while talking) but the shape is rigid enough to insert a 3D printed (or plastic injection molded) filter assembly. It accepts a standard-sized  3.125" N95 disc filter manufactured by MSA, Honeywell and Moldex. 

Fit 

There are 5 sizes of flat patterns that were designed to fit the 5 standard head forms created by NIOSH. I created solid models of each head form, 3D printed them and used these as fit models to develop and test each flat pattern. They all accept the same 3D printed filter assembly and the harness has adjustable velcro straps

Continuous Seal and Airtight Features

Great care was taken in the design and construction to ensure there are no holes or gaps. A neoprene (or hypoallergenic silicone) inner gasket around the interior edge of the mask forms an airtight seal on the face. The fabric flexes with the skin so the user can talk, yawn and make facial expressions without breaking the seal. A neoprene gasket in the center opening ensures an airtight seal for the filter assembly and a waterproof tape is heat bonded to seams to seal areas where the needle punctured the fabric. 

Harness

A harness made from nylon mesh attaches to the mask with magnets and can be pulled off the face with one hand. A similar magnetic fastener is used in CPAP masks. This is useful for scenarios where a user would need to remove the mask quickly or multiple times per day. In law enforcement, masks are a grab risk and pose a threat to officers and a quick release function such as this reduces that risk. There is an option for a non-magnetic harness.

Mask Removal Video Demo

Comfort

Since the mask is made from soft materials used in athletic wear, it conforms to the skin, wicks away sweat and does not cause bruising or sores. It is also very lightweight. Breathing is comfortable and strenuous activity can be performed while wearing the respirator. 

Fogging

There is a replaceable aluminum nose bridge that forms a tight seal on the nose. Because the mask fits well and forms a tight seal, it has not yet caused glasses or goggles to fog.

Exhaust

There is no exhaust valve in the mask. When the wearer breathes in, the seal is airtight and on exhalation, the air is directed through the filter. If the wearer exhales with force, the mask lifts at the bottom and the breath is directed toward the neck and theoretically any aerosols would adhere to the wearer's skin and clothing.

Manufacturing

This mask was designed to be mass produced. The fabric mask can be produced by a manufacturers in the soft goods industry and I am seeking suitable partners that are preferably GMP certified. I will also provide a "tech pack" of plat patterns, specific construction techniques and assembly instructions that can be shared with manufacturers.

Testing

I will mail samples of fully functional prototypes out for testing. I am aware of the clinical testing protocols recommended by the VHA and have desgined the mask around these requirements. User testing with first responders is being conducted separately.

Cleaning & Testing

Sanitization between uses has not yet been tested and will depend on the fabric used in the final design. Ballistic nylons and spacer mesh can be handwashed, placed in the top rack of the dishwasher or under UV light. Some PVCs will tolerate chemical cleaners. I am working with textile mills to determine which high performance fabrics will be best to use based on my requirements and will publish cleaning instructions for each fabric/component.