Mask is an object normally worn on the face, typically for rotection, disguise, performance, or entertainment. Masks have been used since antiquity for both ceremonial and practical purposes, as well as they are usually worn on the face, although they may also be positioned for effect elsewhere on the wearer's body. a covering made of fibre or gauze and fitting over the nose and mouth to protect against air pollutants, or made of sterile gauze and worn to prevent infection of the wearer or (in surgery) of the patient it is a a covering for all or part of the face, worn as a disguise, or to amuse or frighten others.
Classification of masks:
Surgical face mask
Particular Respirators( This is most suitable for Protection against bacteria and Viruses)
Low barrier mask with comfortable tie-on laces suitable for procedures with low levels of spray and splatter such as fluoride treatments, minor orthodontics and basic lab work construction and materials providing adequate protection and comfort. Single pleat design prevents fluid pooling and cross contamination non-woven inner layer for superior protection adjustable nose piece and tie-on for comfortable fitting. Extra long laces fit with a variety of facial shapes and sizes. Comfort Mask are basic masks which is used for Dust and large partials. These are used in dusty environment it protects from wet droplets which are present in environment. This mask is a 7" soft, clean mask secured with ear loops intended for use in a clean room environment. This moderate barrier fluid resistant disposable surgical facemask combines high filtration with comfort and breathability.
Surgical face mask:
A Surgical mask is a loose-fitting, disposable device that creates a physical barrier between mouth/nose of wearer and potential contaminants in the immediate environment. It also prevents patients from direct transmission of infectious agents from health care professionals these type of masks are not PPE as defined under European Directives for PPE
Spun bonded Non woven fabric
- Polyethylene terephthalate (PET)and polypropylene.
- Thermal bonding or resin bonding
- Bonding should be throughout the web
- Soft on skin
- Air permeable
- Water proof
- Can be sanitized
- Easy to stitch
The typical respiratory rate for a healthy adult at rest is 12-20 breaths per minute a 70 kg human breathes 20m3/day. This shows the importance of air purification in human life. air pollution from dust is an essential threat to human health. the process of removal of dispersed particles in the air by the porous medium is called filtration dispersed particles may be solids or liquids, whereas the dispersing medium may be gas (mostly air) or liquid nonwovens are the basic material used for purifying air from aerosol impurities in the form of solid or liquid particles. The porous media used in the filtration process are differentiated by structure, which can be fibrous, granular, and capillary.
Types of Respirators:
Specifications of Respirators
An N95 respirator – PPE designed to achieve a very close facial fit and very efficient filtration of airborne particles.
Bacterial filtration efficiency 3STM F2101
|• Designed for measuring bacterial filtration efficiency of surgical face masks using Staphylococcus aureus as the challenge organism.|
• A bacterial challenged aerosol is passed through the test specimen either face side or inner side at a flow rate of 28.3 L/min
• Evaluation of filtration efficiencies related to both patient generated aerosols and wearer generated aerosols.
• The mean particle size of the bacterial aerosol used in this test is maintained at 3.0+0.3 urn as per relevant ASTM specifications.
• Higher BFE, better the protection level.
• Classifications of surgical face masks as per BFE in European standard EN 14683 is as follows:
BFE > 95% indicates the Type-I surgical face masks
BFE > 98% indicates the Type-II surgical face masks.
|Breathing resistance (∆P) BSEN 13274- 3 - 2001 & EN 143|
|Used to determine the resistance of airflow through the facemask.|
• The surgical face mask is subjected to controlled flow of air.
• The difference in airflow pressure of inlet and outlet of the sample is measured.
• The difference in pressure is divided by the surface area (in cm2 ) of the sample.
• A lower in breathing resistance indicates a better comfort level to the end user Classifications of surgical face masks based on breathing resistance are as follows:
• For Type-I and II surgical face masks(non-splash resistant surgical face masks) <3.0 mm H20/cm2 .
• For Type-IR and IIR surgical face masks,(splash resistant surgical face masks) < 5.0 mm H20/cm2
• Lower the breathing resistance values per cm2 higher the comfort.
• For that, the available surface area of the facemask is increased and thereby the total area available for ventilation is increased.
Splash resistance (ASTM F1862-07):
|· Higher splash resistance, better protection|
· Classifications of surgical face masks based on splash resistance in European standard EN 14683 are as follows:
Ø For Type-I and Type-II surgical face masks, this test is not applicable.
Ø For Type-IR and Type-IIR surgical face masks, the specimen should be tested under the constant velocity of 120 mm Hg
|Flammability (16 CFR 1610):|
· There are many potential ignition sources in the operating room, including surgical lasers, electrosurgical units, endoscopic fiber optics and high-energy electro-medical devices.
· The materials used in operation theatre will burn if high intensity heat energy is applied to them, especially in the presence of elevated oxygen levels.
· Hence, the flammability test for surgical face masks is essential.
· The standards given below are used to determine the flammability by class for medical device like surgical face masks (Guidance for Industry and FDA staff, 2004).
· Consumer Product Safety Commission (CPSC) 16 CFR1610: Standard for flammability of clothing textiles.
· National Fire Production Agency (NFPA) Standard 702-1980: Standard for classification of flammability of wearing apparel.
· Underwriters Laboratory (UL) 2154: Fire test for surgical fabric.
· The flame spread characteristics are classified in terms of class 1 to class 4 for the above tests.
· For NFPA, class 1- slow burning
Ø But as per CPSC standards, class 1 indicates that minimum of 3.5 sec or more required to ignite and spreading of flame on the specimen against the standard flame. In case of UL standards, test to measure the quantity of atmospheric oxygen required to propagate the flame while ignition is caused by an electro surgery unit or laser unit.
Higher LOI, more flame resistant