Useful Info

1. Differences between surgical masks, N95 respirators and surgical N95 respirators

Surgical MaskN95 RespiratorSurgical N95 Respirator
Helps to protect the wearer from large-particles droplets of blood or body fluids which may contain germs (virus and bacteria).Help to reduce exposure to very small airborne particles or contaminants.Helps to protect wearer from large droplets of blood or body fluids and very small particles/fine aerosolised droplets (from cough).
US FDA cleared –510 (k) approval numberNIOSH approved – TC approval numberUS FDA cleared – 510 (k) approval number 
NIOSH approved – TC approval number
Loose fittingTight fit – Form a seal around the nose and mouthTight fit – Form a seal around the nose and mouth
Bacterial filtration efficiency (BFE) above 95%Particulate filtration efficiency (PFE) – minimum 95% against particulate matter (0.3 microns in size) free of oilParticulate filtration efficiency (PFE) – minimum 95% against particulate matter (0.3 microns in size) free of oil
Fluid resistant  (Resistant to penetration of body fluid)Not tested for fluid resistanceTested to be fluid resistant
For healthcare settingFor industrial use (e.g. construction worker) where workers are exposed to dust and small particles During haze seasonsFor healthcare setting –To protect both patients and health care personnel from the transfer of microorganisms, body fluids and particulate matter.
* FDA – Food and Drug Administration
* NIOSH – National Institute for Occupational Safety and Health

2. Applicable standards:

Manufacturing Facilities – To ensure good quality management system 
ISO 9001:2015 Quality Management System
ISO 13485 Medical devices – Quality Management System

Standard Specification for Performance of Materials used in Medical Face Masks
ASTM F2100-19 – Test mask material on bacterial filtration efficiency, differential pressure, particulate filtration efficiency, resistance to penetration by synthetic blood and flammability. Assign a numerical rating for the barrier performance of the material:

Level 1 – for low risk of fluid exposure
Level 2 – for moderate risk of fluid exposure (Pasture 3-ply earloop surgical mask)
Level 3 – for high risk of fluid exposure

Reference: Nelson Labs Medical Face Mask Tests and Requirements –
https://www.nelsonlabs.com/wp-content/uploads/2020/03/Face-Mask-Testing-Requirements.pdf


3. Terms and Definitions:

TermsDefinitions
PM 2.5PM stands for particulate matter which is a mixture of solid particles and liquid droplets found in the air such as dust, dirt or smoke. PM 2.5 are fine particles with diameter less than 2.5 micrometers, which are inhalable and thus detrimental to human health.
Bacterial filtration efficiency (BFE)
  • Measure how efficient the mask is able to filtrate against bacteria
  • Presented in percentage of bacteria larger than 3 microns filtered out by the mask
  • Minimum requirement = 95%
Particulate filtration efficiency (PFE)
  • Measure how efficient the mask is able to filtrate against small particles
  • Presented in percentage of particles larger than 1 micro filtered out by the mask
  • Minimum requirement = 95%
Synthetic blood penetration for liquid
barriers

(i.e Fluid resistance)
  • Evaluate the resistance of the mask to penetration by a small volume of synthetic blood at high velocity (80mmHg, 120mmHg).
  • Pass/fail based on visual evidence of synthetic blood penetration
  • Minimum requirement = 80 mmHg (N95 and 3 ply masks)
  • Can go up to 120mmHg for 3-ply surgical mask
  • Higher value → better resistance
Differential Pressure (DP)
(i.e Breathability)
  • Measure how air is easily passed from one side of the mask to the other.
  • Indicate how easily the wearer can breathe through the mask.
  • Higher value → more difficult to push the air through (Higher breathing resistance) → Lower
    breathability (less comfortable), but better air filtration
ScorePerception
Above 5.0Hot
4.0 to 5.0Very Warm
3.0 to 4.0Warm
2.0 to 3.0Cool
1.0 to 2.0Very Cool
Flammability
  • Determine the time of flame spread for the mask material
  • Minimum requirement = Class 1 flammability (exhibit normal flammability)