Technical
Contents
Testing Standards and Requirements
ISC Technology Readiness Level Scale
ISC is Innovative Solutions Canada They have a chart that defines the stages of development. Technology Readiness Levels (TRL) describe the different stages of pre-commercial development. Find TRL 1 to 9 definitions, descriptions and examples.
Currently 2020-4-17 at between levels 5.TRL and 6.TRL . Funding is looking for projects in the 7.TRL to 9.TRL
Standard Sizes
ISO Digital Headform Sizes
The National Personal Protective Technology Labratory (NPPTL) has NIOSH Anthropometric Data and ISO Digital Headforms available in .stl .ply and .igs format. The five nominal sizes are:
- Small
- Medium
- Large
- Long/Narrow
- Short/Wide
The headforms will be available from NIOSH for those who complete the data use agreements. To obtain the digital headforms or more information, please contact Dr. Ziqing Zhuang at ZZhuang1@cdc.gov .
This ISO standard is available for purchase ISO/TS 16976-2:2015(en) Respiratory protective devices — Human factors — Part 2: Anthropometrics
This ISO standard is available online and for free as part of the Covid19 response ISO/TS 16976-8:2013(en) Respiratory protective devices — Human factors — Part 8: Ergonomic factors
NIOSH Testing Procedure Head Classifaction Size
The Facepiece Fit Test procedure requires the participants to be classified by size and provides a chart and a procedure to classify the 10 different sizes. See pages 10 and 11 of the Determination of Qualitative Isoamyl Acetate (IAA) Facepiece Fit Test
Current Parametric Dimensions of Sizes
Using the Table 5 from ISO/TS 16976-2 for the Mean Sizes of the "5 defined headforms"
I made the following assumptions:
- Mask Width = 70% of Face Width
- Mask Height = Face Height - 40% of Nose Height - 70% of Mouth to Chin Height
- Mask Depth = 40% of Face Width
| Size | Face Height | Face Width | Mask Height | Mask Width | Half Width | Mask Depth | Connector Size | Connector Height |
|---|---|---|---|---|---|---|---|---|
| Small | 4.3" | 5.0" | 2.47" | 3.53" | 1.76" | 1.41" | 1.00" | 0.70" |
| Medium | 4.7" | 5.5" | 2.71" | 3.86" | 1.93" | 1.54" | 1.40" | 0.75" |
| Large | 5.0" | 5.7" | 2.92" | 4.02" | 2.01" | 1.61" | 1.40" | 0.75" |
| Short Wide | 4.6 | 5.8" | 3.18" | 3.22" | ||||
| Tall Narrow | 5.1 | 4.3" | 2.68" | 3.57" |
Contact with Skin
The standard is available for free as part of the COVID response ISO 10993-1:2018 Biological Evaluation Of Medical Devices - Part 1: Evaluation And Testing Within A Risk Management Process
This document applies to evaluation of materials and medical devices that are expected to have direct or indirect contact with:
— the patient's body during intended use;
— the user's body, if the medical device is intended for protection (e.g., surgical gloves, masks and others).
Filter Requirements
N95 Specifications
The buyandsell.gc.ca website has the technical requirements for the N95 masks I created a screen capture of the table at this link
| N95 Spec | Typical |
|---|---|
| Filter Performance | >=95% |
| Test Agent | NaCl |
| Flow Rate | 85 l/min |
| Inward leakage | <=8% |
| Inhalation Resistance | <=343 Pa |
| Flow Rate | 85 l/min |
| Exhalation Resistance | <=245 Pa |
Face Fit Test Procedures
The CDC has Standard Respirator Testing Procedures has test procedures for:
- TEB-APR-STP-0005, 0005a, and 0006Cdc-pdf Determination of Qualitative Isoamyl Acetate (IAA) Facepiece Fit Test
- RCT-APR-STP-0067Cdc-pdf Particulate Respirator Qualitative Fit Test Utilizing Saccharin or Bitrex Solutions
Test in Cough Chamber
Found this article on web Scientists built 'cough chamber' to see how far droplets actually travel
What researchers at Western University, in collaboration with virologists from Toronto's Sunnybrook Hospital, found is that when someone coughs without covering their mouth, the germ-laden cloud of fine mist they release will not only travel two metres in three seconds, it will continue to travel beyond and even float in the air within that two-metre area for up to three minutes after being released.
Need to find out if they can test our masks.
