BE Mask Version 1.0
| BECMv1
The BE Mask 1.0 (BECMv1) is a crisis mask design derivative of the Montana Mask. This iteration includes improvements to materials, assembly process, seal, sizing in relation to geometric scaling, and filter cartridge design. It is an ongoing community effort that continues to adapt to meet the needs of those at the most risk.
Montana Mask vs. BE Mask 1.0
| Montana Mask | BE Mask 1.0 | |
| Mask Frame Material | PLA body recommended | TPU body recommended |
| Sizing | 2 sizes (S – L) Custom scaling | 6 sizes (XXS-XS-S-M-L-XL) Custom scaling |
| Filter Testing | Testing with cut up N95 mask (6 filters) | Polypropylene MERV15 (single use, 2-ply) |
| Community forum | No | Yes |
| Licence | Open Source Non-commercial | Open Source Commercial |
| Production | No | Yes |
Design Iteration
Materials
We made a design that can be printed in a semi flex TPU material which allows a seal without added gasketing materials. We have researched other components to find the safest available materials and included our sourcing links.
Assembly
We have adjusted the eyelets in the design to ease the strapping assembly and support a wider range of materials.
Seal
Both through the materials we’ve chosen and the scaling improvements, the mask seal has been a major focus for our team.
Sizing
We have developed a series of sizes to improve fit comfort for a variety of individuals across a span of ages to minimize leakage and improve safety.
Filter
We have added an interlocking filter cartridge lattice that protects the filter from making direct contact with the face. We have also had success with a 2-ply filter providing an added layer of safety.
Sizing
The BECMv1 comes in 6 sizes; XXS, XS, S, M, L, and XL. The sizes we have chosen are based on research and testing of common face geometries.
Measure the distance between the bridge of your nose at the level of your eyes and the edge of your chin. Pick the size that is closest to your measurement. Mask should fit snugly, without gaps around the edge.
A mask is only fully effective with the correct fit.
Mask Sizes (Chin to Nose): XL: 134 mm (~5 1/4 in) L: 131 mm (~5 1/8 in.) M: 127 mm (~5 in.) S: 122 mm (~4 3/4 in) XS: 118 mm (~4 5/8 in) XXS: 115 mm (~4 1/2 in) |  |
Mask Size Details
| X | Y | Z | |
| XXSmall | 86.16mm | 114.80mm | 74.31mm |
| XSmall | 92.45mm | 119.22mm | 74.31mm |
| Small | 98.36mm | 123.43mm | 74.31mm |
| Medium | 105.04mm | 128.05mm | 74.31mm |
| Large | 109.41mm | 131.88mm | 74.31mm |
| XLarge | 109.75mm | 135.04mm | 74.31mm |
Filter Frame Size Details
| X | Y | Z | |
| XXSmall | 35.57mm | 39.76mm | 9.9mm |
| XSmall | 40.56mm | 43.39mm | 9.9mm |
| Small | 43.15mm | 44.93mm | 9.9mm |
| Medium | 46.08mm | 46.61mm | 9.9mm |
| Large | 48mm | 48mm | 9.9mm |
| XLarge | 48.15mm | 49.15mm | 9.9mm |
Printable Sizing Guide
Cut and use to measure user face for sizing. Dispose after each use.
Testing
Saccharine Fit Test
Report File: April 10 2020
3D PRINTED MASK TRACKING AND TESTING REPORT
(For Mask Fabricator)
| MASK ID (code written on mask) | Praveen’s |
| Mask Size (If applicable) | Medium |
| Mask Material | TPU |
| Filter Material | MERV-15 |
| Other |
| Wearer 1 (Female) – Medium | |
| Mask Fit | (Snug / Loose / Gaps / too large / too small) |
| Comfort | (Comfortable / Uncomfortable) |
| Breathing | (Acceptable / Unacceptable) |
| Breathing compared to N95 Mask | (Same / Harder / Easier) |
| Ease of donning mask | (Easy to put on / Difficult to put on) |
| Filter Assembly | (Easy to assemble / Too difficult / Confusing) |
| Comments: I did not change out the filter; overall comfortable | |
| Wearer 2 (Male) – Medium | |
| Mask Fit | (Snug / Loose / Gaps / too large / too small) |
| Comfort | (Comfortable / Uncomfortable) |
| Breathing | (Acceptable / Unacceptable) |
| Breathing compared to N95 Mask | (Same / Harder / Easier) |
| Ease of donning mask | (Easy to put on / Difficult to put on) |
| Filter Assembly | (Easy to assemble / Too difficult / Confusing) |
Comments:
| Other Testing | |
| Saccharine Test Result | Passed (wearer #1 female) Leak (wearer #2 male) |
| Swab test (if performed, attach) | |
| Other test (describe) | |
| Other test (describe) |
Comments: Sizing was appropriate for wearer #1 (female) and inappropriate for wearer #2 (male).
Correct sizing may be critical for successful use.
3D PRINTED MASK TRACKING AND TESTING REPORT
(For Mask Fabricator)
| MASK ID (code written on mask) | |
| Mask Size (If applicable) | Large |
| Mask Material | TPU |
| Filter Material | MERV-15 |
| Other | |
| Comments: I did not change out the filter | |
| Wearer 1 (Male) – Large | |
| Mask Fit | (Snug / Loose / Gaps / too large / too small) |
| Comfort | (Comfortable / Uncomfortable) |
| Breathing | (Acceptable / Unacceptable) |
| Breathing compared to N95 Mask | (Same / Harder / Easier) |
| Ease of donning mask | (Easy to put on / Difficult to put on) |
| Filter Assembly | (Easy to assemble / Too difficult / Confusing) |
Saccharine Test Result: Some Saccharine taste at very end of testing with head movements.
Comments: Improved performance. Sizing may contribute to success.
Wearer #1 (male) may need an XL mask for complete seal
Conclusion
Testing supports the need for more than 2 sizes, which guided the design to include a series of 3-6 sizes.
Files and Downloads
Download | STL files for BE Mask Version 1 (BECMv1). Includes 6 mask sizes and 6 filter frame sizes.