During the COVID-19 pandemic in recent years, despite being provided with N95 masks and other personal protective equipment, many health care workers were still infected with COVID-19, some even had debilitating situations and ended up staying in an ICU unit for emergency care. In addition to the lack of protection of currently used personal protective equipment, uncomfortable sealing material also rendered the skins of many health care workers irritant and allergic.

Problem definitions:

• Present design of PPE’s (Personal Protective Equipment) for health care workers are flawed

  • Take too long to put on (over 30 seconds)

  • Gap between the mask and the face (does not fit all face shapes)

  • Sealing makes skins uncomfortable

• Large Companies such as 3M, Honeywell are unwilling to take initiatives in improving their current protective products

Thus, this project’s main objective is to redesign and improve upon the current respirator designs, and bring quality working conditions for all health care workers.

Targeted customer:

• • Health care workers

  • Laboratory personnel whose working environment involves tiny and poisonous particles

Requirements of the final half-mask respirator design:

• • Under 30 seconds donning

  • Tight fit against all face shapes

  • The filter cartridge can be replaced easily and efficiently

Requirements of the final test bed design:

• • Constrain the respirator prototype in designated testing area

  • Perform testings on the respirator, generate quantified data that indicates fitness and protection results

  • Accurately simulate the actual fitting scenario of health care workers

  • Reusable

Primary Objectives:

• Design EHMR(Elastomeric Half Mask Respirator) that can stay firmly attached to faces under HCWs’ working conditions

  • Different head forms (under 30 seconds doning)

• Use ASTM standard to test filter cartridge material

  • Generate data using ASTM testing apparatus

• Use a provided material to achieve desired seal.

Secondary Objective:

• Make the filter cartridge replaceable.

• Design a sterilizing box for filter cartridges

There are two deliverables for the project：

One (1) mask design with:

• Rigid part for structure and silicone part for sealing

• Replaceable filter holder

• 3D printed mold for silicone casting

One (1) testing apparatus

• Includes an acrylic box, a 3D printed head model, an air pump, a pressure sensor, an Arduino with related circuits, and a pair of particle counters.

Respirator design consists of five parts: (1) filter cartridge, (2) connection piece, (3) silicone body, (4) silicone seal, and (5) strap

• The curvature part bends inward when a force is applied in order to provide a comfortable seal

• The part that attaches the face will be molded with a color changing silicone that changes color due to a change in temperature

Both designs enable users to easily adjust straps by one hand. The main purpose of designing two strap connectors is to fit a different using environment. The magnetic alignment strap connector can shorten the wearing time by automatically aligning the strap to the right position. However, due to the restriction in some medical facilities (e.g. MRI), Health care workers may not be allowed to carry magnets. Thus, users may need to choose the slide-in and fit press connection strap connectors.

The goal of the testbed is to simulate the quantitative testing standards set forth by using different 3-D printed head shapes from OSHA. Based on the five head shapes provided by our sponsor, if our designed respirator can measure a passing fit factor value for all five head shapes then our respirator design should be able to fit the majority of the population's head shapes therefore eliminating the need for multiple sizes.

• The test box is designed of clear acrylic to allow for clear visibility of the uses.

• The air pump has the direction of airflow alternating between positive and negative pressure in order to simulate the normal breathing rate of a wearer.

• If the respirator is designed properly then the concentration of aerosol particles between the head model and respirator will be very small in comparison to the aerosol concentration within the rest of the testbed.

Link to Executive Summary.