Respiratory protection face masks and respirators

A.MURALIKRISHNAN

LECTURER – TEXTILES

P.A.C.RAMASAMYRAJA POLYTECHNIC COLLGE,

RAJAPALAYAM, TAMILNADU, INDIA

Email: [email protected]

Contents

• Introduction

• Personal protective equipments (PPE)

• Types of protection levels

• Classification of masks

• Functional, design, ergonomic requirement, • Functional, design, ergonomic requirement, manufacturing method for surgical face mask

• Difference between respirator and surgical face mask

• Construction of respirator

• Testing and Evaluation methods

Compiled by A.Muralikrishnan, Lecturer, P.A.C.Ramasamyraja Polytechnic college, Rajapalayam, Tamilnadu, India

Personal protective equipment

(PPE)

• "PPE", is equipment worn to minimize exposure to a

variety of hazards.

• PPE also referred to as “equipment designed to

protect the wearer's body from injury or infection”.protect the wearer's body from injury or infection”.

• The hazards may be from physical, electrical, heat,

chemicals, biohazards, and airborne particulate

matter

• Examples of PPE: Masks, gloves, ear plugs, helmets,

goggles, full body suits and etc.


What is P1 or P2 Protection?

• P1 - For filtering mechanically generated particles

– Which meets AS/ NZS1716:2003

– Example : particles formed by crushing, grinding, drilling,

sanding and cutting.

• P2 is - for filtering mechanically and thermally generated • P2 is - for filtering mechanically and thermally generated

particles

– Which meets AS/NZS1716:2003,

– Example: Welding fume, against some bio aerosols such as

H1N1 and H5N1 Influenza.


Classification of face mask

• Based on the function

– Comfort mask

– Surgical face mask

– Surgical Respirators– Surgical Respirators

– Particulate respirators

• Based on usage

– Disposable

– Reusable


Selection of suitable mask


Size of various particles

The following particles are more dangerous to human

health


Surgical masksIntroduction:

• A surgical mask is a loose-fitting, disposable device that creates

a physical barrier between the mouth/nose of the wearer and

potential contaminants in the immediate environment.

• It also prevent patients from direct transmission of infectious

agents from health care professionals or the surgical area.

• Surgical masks are not PPE as defined under the European

Directive 89/686.


Functional requirements of surgical

mask

• Prevent the spread of infection between sick and well persons

– Simple surgical masks should protect wearers from being

splashed with body fluidssplashed with body fluids

– Prevent transmission of body fluids from the medical

professional to the patient.

• Should have sufficient filtration efficiency to Bacterial and

aerosol particles.


Design Requirements• Should have fluid proof and splash resistance to blood and

body fluids

• Should have pleats/folds – For allowing the user to expand the

mask so as to cover the nose and under the chin.

– Commonly 3 pleated are used

• Should have stability during breathing,

– i.e. The mask should maintain its shape in a better way during breath.

• Should have minimum pore size for efficient filtration

• In case of higher filtrations, 3 ply material is made up from a

melt blown placed between spun bonded non-woven fabric,

– the melt-blown material acts as the filter that stops

microbes from entering or exiting the mask.

• Should have additional filtration media for effective filtration

(Optional)Compiled by A.Muralikrishnan, Lecturer, P.A.C.Ramasamyraja Polytechnic college, Rajapalayam, Tamilnadu, India

Ergonomic requirements

• Should be breathable and have less breathing resistance.

• Loosely cover the mouth and nose

• It should have two headbands, nose foam and nose clip.

• Should have elastic strap band instead of tie-on strap.

• Made of soft materials and be comfortable to wear.• Made of soft materials and be comfortable to wear.

• Should be light in weight


Aesthetic requirements

• Different in colour

• Masks with designs for attracting kids


Flow chart of face mask production


Structure of surgical Mask


Filtration fabric manufacturing

• Nonwovens are basically used for purifying

aerosol impurities in the form of solid or liquid

particles.

• The disposable facemasks are made up of spun • The disposable facemasks are made up of spun

bond and melt blown nonwovens.


Spun bonded Non woven fabric

• Raw materials:

– polyethylene terephthalate (PET) and polypropylene.

• Bonding method:

– Thermal bonding or resin bonding

– Bonding should be throughout the web

• Benefits• Benefits

– Soft on skin

– Disposable

– Air permeable

– Water proof

– Can be sanitized

– Easy to stitch

• GSM Range: 15 - 30Compiled by A.Muralikrishnan, Lecturer, P.A.C.Ramasamyraja Polytechnic college, Rajapalayam, Tamilnadu, India

Properties of Spun bond non woven

fabric


Melt blown non woven fabric• Composed of super-thin, non-continuous fibres.

• Melt- blown nonwoven are characterised by random

arrangement of fibres.

• Stability is achieved mainly by the cohesion forces, as the

fibres are mutually glued during solidification.

• Polypropylene (PP) has a low melting point and is the most • Polypropylene (PP) has a low melting point and is the most

popular polymer for melt-blown nonwovens.

• The following polymers can also be used:

– polyethylene terephthalate (PET),

– polyamide (PA) and its copolymers,

– polyethylene (PE),

– polycarbonates (PCs),

– simple and complex polyurethanes (PU).Compiled by A.Muralikrishnan, Lecturer, P.A.C.Ramasamyraja Polytechnic college, Rajapalayam, Tamilnadu, India

Properties of MB fabric


Classification based on performance


What should I know before using surgical

masks?

• Surgical masks will not fully protect you from being infected.

• Masks must be changed when they become wet with saliva or other bodily

fluids, as they lose their protective properties.

• Surgical masks are not tested against specific requirements. • Surgical masks are not tested against specific requirements.

• Never reuse, wash or disinfect surgical masks.

• Never share surgical masks with others.

• Place used or soiled masks into a tied plastic bag to prevent dripping.


Respiratory Protection


Introduction• The typical respiratory rate for a healthy adult at rest is 12–20

breaths per minute.

• A 70 kg human breathes 20 m3 /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.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.Compiled by A.Muralikrishnan, Lecturer, P.A.C.Ramasamyraja Polytechnic college, Rajapalayam, Tamilnadu, India

Difference between masks and respirators

Surgical masks Respirators

Surgical masks are not PPE Respirators are PPE

Surgical masks prevent droplets being

expelled into the environment by the

used to reduce the potential contact of

the wearer to airborne hazardous expelled into the environment by the

wearer and protect patients and

operative site.

the wearer to airborne hazardous

contaminants.

Un valved: Valved:


Classification of Respirators

• FFP1 respirators – Suitable for lower filtering

efficiency and protection factor.

• FFP3 respirators - For highest levels of

filtering efficiency and protection factor. filtering efficiency and protection factor.


Respirator fabric Structure• It consists of 3 layers

– Nonwoven needle felt or melt blown middle layer

– Surrounded by spun bonded inner and outer layer.

• The structure and design of the multilayer materials depend

on their application.


Needle punched filter fabric

Influencing parameters on filtration efficiency:

• Fibre diameter, areal density, thickness of the filtration layer,

and the fibre blend's composition

• Effect of filtration is maintained by these non woven are at

least five months after manufacturing. least five months after manufacturing.

• The air flow resistance for the above-mentioned nonwovens is

not higher than 51 Pa.


Particulate Respirators


Valved Respirators


Specifications of Respirators• An N95 respirator – PPE designed to achieve a very close facial

fit and very efficient filtration of airborne particles.

• The following notations are called for respirator description.

– N – Not Resistant to Oil

– R – Somewhat Resistant to Oil

– P – Strongly Resistant to Oil (Oil Proof)– P – Strongly Resistant to Oil (Oil Proof)

• N95 respirators remove at least 95% of airborne particles with

a size of 300nm (0.3 micron)

• N99 respirators remove at least 99% of airborne particles

• N100 respirators remove at least 99.97% of airborne particles


3M - Product description

• The 3M 9004 IN is a dust mask composed of three layers of

filters.

– Outermost layer filters out the largest dust particles,

– Innermost layer preserves the respirator and– Innermost layer preserves the respirator and

– Middle layer is composed of electrostatic filter media.

– It has the ability to filter above 90% of 0.3-micron

particulate dusts. (Scientific research has proven that for

all dust particles sizes, 0.3 micron dust are the most

difficult to filter effectively).


Testing and Evaluation of

Masks and RespiratorsMasks and Respirators


Bacterial filtration efficiency

ASTM 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 • The mean particle size of the bacterial aerosol used in this test is

maintained at 3.0±0.3 µm 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 (ΔP)

BS EN 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. 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 H2O/cm2 .

• For Type-IR and IIR surgical face masks,(splash resistant

surgical face masks) ≤ 5.0 mm H2O/cm2

• Lower the breathing resistance value 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):

• Used to determine the penetration resistance of surgical face

masks

• A fixed volume of synthetic blood (stimulant fluid have

equivalent liquid characteristics like surface tension of actual

blood and other body fluids), is aimed at the specimen and

dispersed at a known velocity.dispersed at a known velocity.

• It simulates the impact of blood or other body fluid onto the

specimen.

• Any evidence of synthetic blood penetration on the back side

of the medical face mask constitutes failure.

• Specimen medical face masks are evaluated at a total of three

different velocities corresponding to human blood pressures

of 10.6, 16.0, and 21.3 kPa (80, 120 and 160 mm Hg).


• Higher splash resistance, better protection

• Classifications of surgical face masks based on splash

resistance in European standard EN 14683 are as follows:

Splash resistance (ASTM F1862-07):

– For Type-I and Type-II surgical face masks, this test is not

applicable.

– 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): Need of flammability test:

• 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 • 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 CFR 1610:

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. class 1 to class 4 for the above tests.

• For NFPA, class 1 - slow burning

– 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 resistantCompiled by A.Muralikrishnan, Lecturer, P.A.C.Ramasamyraja Polytechnic college, Rajapalayam, Tamilnadu, India

Summary of

Testing Testing

evaluation


Leading Manufacturers in Mask and

Respirators

• 3M

• Midas

• Crosstex

• Moldex• Moldex

• Breathe healthy


References

• Textiles for Protection by Richard A.Scott

• Handbook of technical textiles by A Horrocks and S C Anand

• K.P. Chellamani*, D. Veerasubramanian and R.S. Vignesh Balaji

, “Surgical Face Masks: Manufacturing Methods and

Classification” The South India Textile Research Association,

Coimbatore, TN, India

• Respirators selections, <www.3m.com>


THANK YOUTHANK YOU


Respiratory protection face masks and respirators

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