WO2022121263A1

WO2022121263A1 - Respirator with adjustable straps

Info

Publication number: WO2022121263A1
Application number: PCT/CN2021/099388
Authority: WO
Inventors: Ching LAM
Original assignee: VANNEX INTERNATIONAL Ltd; Hong Kong Polytechnic University HKPU
Current assignee: VANNEX INTERNATIONAL Ltd; Hong Kong Polytechnic University HKPU
Priority date: 2020-12-11
Filing date: 2021-06-10
Publication date: 2022-06-16
Anticipated expiration: 2023-06-11
Also published as: CN116761525A

Abstract

Provided herein is a respirator (100, 100A, 100B) with adjustable straps (210, 220) that can achieve tight-fitting on most wearers. The respirator (100, 100A, 100B) includes a mask body (110), an upper strap (210), and a lower strap (220). The mask body (110) is adapted to fit over a mouth and a nose of a wearer. The upper and lower straps (210, 220) are both detachably attached to the mask body (110) by threading through at least one upper anchor structure (231, 231A, 233) and at least one lower anchor structure (232, 232A, 234) respectively. Each of the upper strap (210) and the lower strap (220) comprises markings (240) for indicating at least one upper position on the upper strap (210) and at least one lower position on the lower strap (220). The upper position defines a first length of the upper strap (210) and the lower position defines a second length of the lower strap (220) that the respirator (100, 100A, 100B) fits to the wearer with increased consistency when the upper and lower straps (210, 220) are stretched over the wearer's head.

Description

RESPIRATOR WITH ADJUSTABLE STRAPS

TECHNICAL FIELD

The present disclosure generally relates to a respirator or a face mask. More particularly, the present disclosure relates to a respirator with adjustable straps that can achieve tight-fitting on most wearers.

BACKGROUND

Airborne transmission is generally a disease transmission of various viral diseases through the air. An individual may be inflected by exposing to infectious agent, such as virus-containing respiratory droplets, dusts, and particles. The disease can be transmitted through the air over time and distance , like sneezing that aerosolizing the droplet to nano-sized particle. The recent outbreak of the novel coronavirus COVID-19 is a good example of droplet and occasionally airborne transmission.

COVID-19 can be aerosolized from droplet to airborne and then attached to fine particles, suspended dust particles, or other respiratory droplets of an infected person. A variety of respirators and masks have been designed to be used for protecting wearer from airborne transmission. The respirators remove particulate material and infectious agents from the air before it is inhaled by the wearer, thereby the wearer can be protected. The protection can also be extended to the neighboring persons as any infectious agents are also removed from the air exhaled by the wearer.

The present technology generally adopts non-adjustable head harness and earloop design (not recommended design by the Centers for Disease Control and Prevention) for respirators, particularly for half-mask respirators like N95, N99, FFP2, and FFP3. For working in the isolation wards with patients having highly infectious diseases, the proper use of respirator is vital to the safety of the healthcare workers. To ensure tight-fitting of the respirator and the creditability of the protection, the healthcare worker needs to perform quantitative fit testing prior to the use. Normally, they are required to don a respirator in clinical setting for 2 to 4 hours before changing to another new respirator.

However, there are several problems deserved attention. Human facial anthropometry and head size are in great variety. Some people may have a round face, while some others may have an oval or a square face. People of difference races may also have significant differences in the facial contour. If the respirator doesn’ t fit the wearer’s face, the respirator cannot fully protect the wearer and exposes the wearer to risks of inflection. The tight-fitting respirators may be provided with a range of different models and sizes for selection. To ensure that the respirator can fit and seal properly without leakage, the wearer should first undergo fit test to identify the model and the size that properly fit.

The non-adjustable band of the conventional respirator may not achieve the adequate tightness which may increase the risk of leakage and infection. Besides, if there is too tight, the respirator (when donning for a period of time, like 2 hours) may contribute to pressure sore at nose, ear or head, which leads to contact infectious risk. Mask Usability Scale (MUS) that reflects tolerated heat, breathability, tightness, interference on speaking, skin itchiness, mask displacement, discomfort on ear lobe, duration for use, interference on working efficiency, mist over glasses and overall level of comfort, is good to indicate the performance of donned respirator for working.

WO2020/053786 A2 discloses a respirator including adjustable strap covering various types of face-piece respirators. The respirator is provided with straps threading through a number of apertures to retain the strap in position, which may be adjustable. The aperture includes gripping portion, such as teeth, engaging the strap to prevent the strap from being pulled back. However, the creation of apertures by the means of creating openings on the body of the respirators may reduce the filtering ability of the entire respirator. Since the particulate filtering efficiency (PFE) and fit testing of respirator are tested using 0.3 micron, the openings of the respirator body may give rise to further air leakage, compromising the filtering ability. The disclosure in this PCT publication also provides the use of left and right attachments with one or more slits on linear weld to form an aperture, which the straps can be connected externally without any opening on the body of the respirator. The slits created on the attachments may reduce the air leakage, but with such design the strap is not adjustable. Other approaches of using extra patches attached to the respirator body increase the material cost and the complexity in mass production.

Accordingly, there is a need in the art for an improved respirator that seeks to address at least some of the problems mentioned above. Furthermore, other desirable features and characteristics will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and this background of the disclosure.

SUMMARY OF THE INVENTION

Provided herein is a respirator with adjustable straps that can achieve tight-fitting on most wearers.

According to certain aspects, the respirator comprises a mask body, an upper strap, and a lower strap. The mask body is adapted to fit over a mouth and a nose of a wearer. The upper and lower straps are both detachably attached to the mask body by threading through at least one upper anchor structure and one lower anchor structure respectively. Each of the upper strap and the lower strap comprises markings for indicating at least one upper position on the upper strap and at least one lower position on the lower strap. The upper position defines a first length of the upper strap and the lower position defines a second length of the lower strap that the respirator fits to the wearer with increased consistency when the upper and lower straps are pulled against the upper and lower anchor structures and stretched over the wearer’s head.

According to certain aspects, the mask body comprises a breathable zone, the upper and lower anchor structures are provided on perimeter regions of the mask body outside the breathable zone.

Preferably, the perimeter regions comprise one or more attachments.

According to certain aspects, the upper and lower anchor structures are selected from the group consisting of staples, clips, pins, fasteners, and other attachment means.

According to certain aspects, the upper and lower anchor structures and the mask body are formed integrally.

According to certain aspects, the upper and lower straps are made of polyisoprene for providing a tension force to keep the respirator in position without slipping off.

According to certain aspects, the upper and lower straps are made of rubbers selected from the group consisting of natural Gutta-percha and synthesized trans-1, 4-polyisoprenes; natural rubber and synthesized cis-1, 4-polyisoprene; poly-cis-isoprene; and other polymers and petroleum-based monomers.

According to certain aspects, the upper and lower straps are attachable to a front side of the mask body.

According to certain aspects, each of the upper and lower straps has a first end welded to the mask body and a second end adjustably attachable to the mask body.

According to certain aspects, the upper strap has a first end adjustably attachable to the mask body through a first upper anchor structure, and a second end adjustably attachable to the mask body through a second upper anchor structure. The lower strap has a third end adjustably attachable to the mask body through a first lower anchor structure, and a fourth end adjustably attachable to the mask body through a second lower anchor structure.

Preferably, the markings comprise left markings provided on the first end and the third end, and right markings provided on the second end and the fourth end.

According to certain aspects, the markings are evenly spaced across a longitudinal length of the upper and lower straps for providing visual indications of the upper position and the lower position.

According to certain aspects, the markings are scribed, printed, engraved, stamped, or embossed on the upper and lower straps.

This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. Other aspects and advantages of the present invention are disclosed as illustrated by the embodiments hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

The appended drawings contain figures to further illustrate and clarify the above and other aspects, advantages, and features of the present disclosure. It will be appreciated that these drawings depict only certain embodiments of the present disclosure and are not intended to limit its scope. It will also be appreciated that these drawings are illustrated for simplicity and clarity and have not necessarily been depicted to scale. The present disclosure will now be described and explained with additional specificity and detail through the use of the accompanying drawings in which:

FIG. 1 illustrates a front perspective view of a respirator in accordance with certain embodiments of the present disclosure, being donned by a person;

FIG. 2 is a front view of the respirator in a first configuration in accordance with certain embodiments of the present disclosure, when the respirator is flat-folded;

FIG. 3 is a front view of the respirator of FIG. 2, when the straps are stretched;

FIG. 4 is a conceptual diagram illustrating the cross-sectional side view of the respirator of FIG. 2;

FIG. 5 is a rear view of the respirator of FIG. 2, when the respirator is fully opened;

FIG. 6 is a front view of the respirator in a second configuration in accordance with certain embodiments of the present disclosure, when the respirator is flat-folded;

FIG. 7 is a front view of the respirator in a third configuration in accordance with certain embodiments of the present disclosure, when the respirator is flat-folded;

FIG. 8 is a rear view of the respirator of FIG. 7, when the respirator is fully opened;

FIGS. 9A-9F illustrate the steps for donning the respirator of FIG. 2 in accordance with certain embodiments of the present disclosure;

FIG. 10 is a graph showing the face area distribution in Chinese healthcare workers obtained from a survey in Hong Kong;

FIG. 11 is a table showing the fit test passing rate of the respirator comparing with the conventional 3-panel model respirator and cup-shaped model respirator;

FIG. 12 is a table showing the usability (20-minute donning) of the respirator comparing with the conventional N95 respirator; and

FIG. 13 is a table showing the usability (2-3 hours donning) of the respirator comparing with the conventional N95 respirator with earloop design.

DETAILED DESCRIPTION OF THE INVENTION

The present disclosure generally relates to a respirator, particularly for non-reusable half-mask respirators like N95, N99, FFP2, and FFP3. It is apparent to one skilled in the art that the term respirator may include other reusable respirators and full facepiece respirators. More specifically, but without limitation, the present disclosure relates to a respirator with adjustable straps that can achieve tight-fitting on most wearers. The adjustable strap in the respirator is cheap yet without compromising the filtration performance, and the design does not require extra patches and allows consistency in performance. This invention particularly offers a low-cost improvement applicable to those non-reusable half-mask respirators, and in certain embodiments, it may also be applied to other reusable respirators as a low-cost improvement.

The following detailed description is merely exemplary in nature and is not intended to limit the disclosure or its application and/or uses. It should be appreciated that a vast number of variations exist. The detailed description will enable those of ordinary skilled in the art to implement an exemplary embodiment of the present disclosure without undue experimentation, and it is understood that various changes or modifications may be made in the function and structure described in the exemplary embodiment without departing from the scope of the present disclosure as set forth in the appended claims.

The benefits, advantages, solutions to problems, and any element (s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential features or elements of any or all of the claims. The invention is defined solely by the appended claims including any amendments made during the pendency of this application and all equivalents of those claims as issued.

As used herein, the term “breathable zone” refers to a zone or a region of the respirator that permits a transport of air from the ambient atmospheric gas space to the interior gas space between a mask body and a wearer’s face, and vice versa.

The term “layer” in a filtering structure refers to a layer of air-permeable material on a respirator, which is adapted for the primary purpose of removing contaminants from an air stream that passes through it.

The term “flat-folded” is used to describe a respirator that is folded flat for storage.

The term “fully opened” is used to describe a respirator that is opened for use.

The term “inhalation” refers to the inhalation, for example, but without limitation, of air by the wearer and includes both oral and nasal inhalations. The term “exhalation” refers to the exhalation, for example, but without limitation, of air by the wearer and includes both oral and nasal exhalations.

The term “mask body” , as used herein, refers to an air-permeable structure that is designed to fit over the nose and mouth of a wearer defining the interior gas space separated from the ambient atmospheric gas space.

The term “perimeter” means the outer periphery of the mask body away from the breakable zone, which would be disposed generally proximate a wearer’s face when the respirator is being donned by a wearer.

Terms such as “upper” , “lower” , “inner” , “outer” , “front” , “rear” , “top” , “bottom” , and variations thereof are used herein for ease of description to explain the positioning of an element, or the positioning of one element relative to another element, and are not intended to be limiting to a specific orientation or position. Terms such as “first” , “second” , and the like are used herein to describe various elements, components, regions, sections, etc., and are not intended to be limiting.

Referring to FIG. 1, there is shown a respirator 100 being donned by a person in accordance with certain embodiments of the present disclosure. The respirator 100 is an air filtration device that is worn by a person to provide the wearer with clean air to breathe. In a preferred embodiment, the respirator 100 is a non-reusable respirator for clinical use in a high level of protection against any aerosol generation procedure. The feature of the respirator 100 is to increase the passing rate of quantitative fit testing for wearers with diverse facial anthropometry and head sizes. It is apparent that the teaching of the present disclosure may also be applied to face masks or other protective masks. In particular, the respirator 100 of the present disclosure is implemented on a half-face respirator, such as N95, N99, FFP2, and FFP3. The respirator 100 comprises a mask body 110, an upper strap 210, and a lower strap 220. The mask body 110 is a central portion of the respirator 100 adapted to fit over the mouth and the nose of the wearer. The upper strap 210 and the lower strap 220 are attachable to the lengthwise of the mask body 110 from the front side of the mask body 110. When the respirator 100 is properly donned by the wearer, the upper strap 210 and the lower strap 220 are stretched over the wearer’s head with extended length, such that the respirator 100 is kept in position without slipping off.

In certain embodiments, the mask body 110 includes a filtering structure disposed on the breathable zone. Therefore, the mask body 110 can remove at least a portion of contaminants, respiratory droplets, dusts, or other particles when the air from the ambient atmospheric gas space enters the interior gas space between a mask body 110 and a wearer’s face through the filtering structure. During inhalation, the air passes through at least a portion of the filtering structure before entering the wearer’s respiratory system. During exhalation, the air released by the wearer passes through the filtering structure to the ambient atmospheric gas space.

The first configuration of the respirator 100, when it is flat-folded, is illustrated in FIG. 2. The mask body 110 is in a 3-panel configuration with a substantially rectangular in shape in flat-folded configuration, and the fully opened configuration is shown in FIG. 4. On the front side of the respirator 100, there is provided an upper strap 210 and a lower strap 220. The upper and

lower straps

210, 220 are adjustable head harnesses or head straps arranged on the front side so that when the two straps are stretched over the wearer’s head, the pulling strength on the straps can keep the mask body 110 in place. Advantageously, the upper strap 210 is adjustably attachable to the mask body 110 by threading through a first upper anchor structure 231 and a second upper anchor structure 233. Similarly, the lower strap 220 is adjustably attachable to the mask body 110 by threading through a first lower anchor structure 232 and a second lower anchor structure 234. The upper and lower anchor structures 231-234 are selected from the group consisting of staples, clips, pins, fasteners, and other attachment means. The upper and lower anchor structures 231-234 have a length larger than the width of the upper and

lower straps

210, 220. As shown in the illustrated embodiments, the anchor structures 231-234 are staples made of stainless steel. In certain embodiments, the staples are characterized with Brinell scale ≤187HB, rockwell hardness of ≤90HRB, and/or Vickers hardness of ≤200HV. Preferably, the staple length is between 8mm to 15mm, while the strap has a width of 5mm to 13mm. In some cases, the upper and lower anchor structures 231-234 and the mask body 110 are formed integrally.

In certain embodiments, the upper strap 210 has a first end 210A adjustably attachable to the mask body 110 through the first upper anchor structure 231, and a second end 210B adjustably attachable to the mask body 110 through the second upper anchor structure 233. The lower strap 220 has a third end 220A adjustably attachable to the mask body 110 through a first lower anchor structure 232, and a fourth end 220B adjustably attachable to the mask body 110 through a second lower anchor structure 234.

In certain embodiments, the upper and lower anchor structures 231-234 are provided on perimeter regions of the mask body outside the breathable zone. Preferably, the perimeter regions comprise one or more attachments 120. Therefore, if the upper and lower anchor structures 231-234 are staples penetrating through the attachments 120, there is no increased risk of leakage or infection. The air from the ambient atmospheric gas space cannot may not enter the interior gas space of the respirator 100 through the upper and lower anchor structures 231-234.

Each of the upper strap 210 and the lower strap 220 comprises markings 240 for indicating at least one upper position on the upper strap 210 and at least one lower position on the lower strap 220. The upper position defines a first length of the upper strap 210 and the lower position defines a second length of the lower strap 220 that the respirator 100 fits to the wearer with increased consistency (after adjusted to the optimal lengths that are determined by quantitative fit test) when the upper and

lower straps

210, 220 are pulled against the upper and lower anchor structures 231-234 and stretched over the wearer’s head.

As shown in the illustrated embodiments, there are markings 240 on the entire width of the upper and

lower straps

210, 220. The markings 240 are evenly spaced across a longitudinal length of the upper and

lower straps

210, 220 for providing visual indications of the upper position and the lower position. The markings 240 are scribed, printed, engraved, stamped, or embossed on the upper and

lower straps

210, 220. It is apparent that the markings 240 may also be segmented into left markings and right markings without departing from the scope and spirit of the present disclosure. In such case, the left markings are respectively provided on the first end 210A and the third end 220A, while the right markings are respectively provided on the second end 210B and the fourth end 220B.

Generally, it is recommended that a wearer should undergo quantitative fit testing before wearing a conventional respirator. The quantitative fit testing has to be repeated if there is significant alternation of the wearer’s body weight or facial contour. The present invention provides a respirator 100 that can achieve tight-fitting on most wearers. This can be achieved by the use of the upper and

lower straps

210, 220, which are adjustably attachable to the mask body 100, and the markings 240 thereon.

As shown in FIG. 3, when the upper and

lower straps

210, 220 are stretched, the upper and

lower straps

210, 220 are pulled against the upper and lower anchor structures 231-234 to fix the position of the upper and

lower straps

210, 220 with respect to the upper and lower anchor structures 231-234. Therefore, if the wearer has tested and identified particular markings, or length of the straps, that can achieve tight-fitting on the wearer, the wearer is only required to stretch the straps by aligning the upper and lower anchor structures 231-234 to such markings such that the position of the upper and

lower straps

210, 220 are fixed with respect to the upper and lower anchor structures 231-234. In a preferred embodiment, the upper and

lower straps

210, 220 are made of polyisoprene, which is a kind of synthetic rubber, for providing a tension force to keep the respirator in position without slipping off. Therefore, the tight-fitting performance can be very consistent and the risk of slipping off is minimal.

In other alternative embodiments, the upper and

lower straps

210, 220 may also be made of other material selected from the group consisting (1) Polyethylene terephthalate (PET) +Spandex; (2) Nylon + Spandex; and (3) Latex (natural rubber) . The material allows the upper and

lower straps

210, 220 to extend the length to a maximum of 3 times of the original length. Considering that a relatively longer of head-strap has to be provided for males who have a large head size, the use of these three materials sacrifices the best fit for users with smaller head size, and some may find difficulties to securely attach and fit with the respirator 100, especially for Asia females.

The preferred embodiment of the present disclosure uses polyisoprene to make the upper and

lower straps

210, 220. The length of the upper and

lower straps

210, 220 can be extended to a length equivalent to 5 times of the original length. With a higher flexibility, the upper and

lower straps

210, 220 are more flexible and easier for wearer to achieve tight-fit. In some cases, a relatively shorter strap may be used so that it can fit for most wearers with different head size. Furthermore, the surface of the polyisoprene is easier to stick to human hair. Therefore, the upper and

lower straps

210, 220 are not easily drop off or slippery during intensive movements. Other types of rubber may also be used to achieve a similar performance, such as (1) natural Gutta-percha and synthesized trans-1, 4-polyisoprenes; (2) natural rubber and synthesized cis-1, 4-polyisoprene; (3) poly-cis-isoprene; and (4) other polymers and petroleum-based monomers. In particular, the most prevalent synthetic rubber is styrene-butadiene rubbers (SBR) derived from the copolymerization of styrene and 1, 3-butadiene. Other synthetic rubbers include (1) polyisoprene, prepared by polymerization of synthetic isoprene; (2) chloroprene, prepared by polymerization of 2-chlorobutadiene; and (3) nitrile rubber made from cyanobutadiene or 2-propenenitrile and butadiene.

FIG. 4 shows a conceptual diagram illustrating the cross-sectional side view of the respirator 100. This is the structure of one possible implementation of the respirator 100. As illustrated, the mask body 110 includes a filtering structure comprises an exterior layer 111 of spunbond polypropylene fabric, a first middle layer 112 of meltblown polypropylene filter layer, a second middle layer 113 of meltblown polypropylene filter layer, and an interior layer 114 of spunbond polypropylene fabric. A nose wire 251, which can be a metal wire covered by plastic, is provided between the first and second

middle layer

112, 113. In some other cases, the nose wire 251 may also be provided at other positions without departing from the scope and spirit of the present disclosure. On the rear side of the respirator 100, a nose foam and a chin foam 252 may also be provided for increasing the comfort of the wearer. On the front side of the respirator 100, the upper and

lower straps

210, 220 are provided, which is already discussed above. In other embodiments, the mask body 110 may also comprise electrically-charged microfibers or nanofibers. In yet other embodiments, the mask body 110 may comprise one or more breathing valves.

FIG. 5 illustrates a rear view of the respirator 100 when the respirator 100 is fully opened by pulling the top panel 115A and the bottom panel 115B at the rear side. The interior gas space inside the mask body 110 is expanded when the respirator 100 is fully opened. On the attachments 120, the staples are applied by a stapler from front to back, such that the staples can prevent the upper and

lower straps

210, 220 from slipping out.

In accordance with a second configuration of the respirator 100, as illustrated in FIG. 6, which is generally designated as 100A. The respirator 100A comprises a mask body 110, an upper strap 210, and a lower strap 220. The mask body 110 is a central portion of the respirator 100A adapted to fit over the mouth and the nose of the wearer. The upper strap 210 and the lower strap 220 are attachable to the mask body 110 from the front side of the mask body 110. The upper and

lower straps

210, 220 are adjustable head harnesses or head straps arranged on the front side so that when the two straps are stretched over the wearer’s head.

The upper strap 210 is adjustably attachable to the mask body 110 by threading through an upper anchor structure 231A, and the lower strap 220 is adjustably attachable to the mask body 110 by threading through a lower anchor structure 232A. In particular, the upper strap 210 has a first end welded to the mask body 110 at an upper joint 241, and a second end adjustably attachable to the mask body 110. Similarly, the lower strap 220 also has a first end welded to the mask body 110 at a lower joint 242, and a second end adjustably attachable to the mask body 110. The connection to the mask body 110 may use other suitable techniques, such as adhering, knotting, mechanically fastening, etc.

In accordance with a third configuration of the respirator 100, as illustrated in FIGS. 7-8, which is generally designated as 100B. The respirator 100B is in a cup-shaped configuration during use and folded flat for storage. The mask body 110 is vertically folded along a centerline 116 of the mask body 110, and so the respirator 100B is usually referred to as a vertical flat-fold respirator. The mask body 110 of the respirator 100B in a cup-shaped configuration has a breathable zone in the middle, and perimeter regions along the periphery of the mask body 110. The perimeter regions are not in the breathable zone, and the perimeter regions are fit onto the wearer’s face during inhalation and exhalation. The upper and lower anchor structures 231-234 are provided on the perimeter regions of the respirator 100B. Unlike the first and second configurations of the respirator 100, there is no attachments 120. However, the risk of air leakage is small as long as the upper and lower anchor structures 231-234 are not within the breathable zone.

FIGS. 9A-9F illustrate the steps for donning the respirator 100 in accordance with certain embodiments of the present disclosure. The wearer needs to perform quantitative fit testing to identify the first length of the upper strap 210 and the second length of the lower strap 220 prior to the use. The first and second lengths are defined by the upper position and the lower position of the markings 240. As demonstrated in FIG. 9A, the wearer adjusts the first and second lengths by moving the upper and

lower straps

210, 220 to align the upper and lower anchor structures 231-234 to the markings 240 at which the respirator 100 fits to the wearer’s head.

The second step, as shown in FIG. 9B, is to pull open the top panel 115A and the bottom panel 115B of the respirator 100, and bend the nose wire 251 at the center. Next, the wearer puts the respirator 100 on by covering the mouth and nose, and stretches the lower strap 220 and upper strap 210 over the head, as demonstrated in FIGS. 9C-9D. The lower strap 220 is stretched to position around the neck and below the ears, and the upper strap 210 is stretched to position at the top of the head. The wearer should also adjust the respirator 100 to a comfortable position by pulling the top panel 115A towards the bridge of the nose, and the bottom panel 115B under the chin.

To ensure the respirator 100 is air tight without leakage, the wearer can place the fingertips of both hands at the top of the nose wire 251 to apply force thereto, as illustrated in FIG. 9E.The force can mold the nose wire 251 to the shape of the wearer’s nose by moving the fingertips down both sides along the nose wire 251.

Finally, as shown in FIG. 9F, the wearer can test for any air leakage at the respirator perimeters regions by performing sharp exhalations and inhalations. If air is leaked, the wearer should re-adjust the nose wire 251 or stretch the upper and

lower straps

210, 220 again.

The fit testing results of the respirator 100 of the first configuration and the respirator 100B of the third configuration were carried out in the Centre for Infection Control in Hong Kong. The facial anthropometries measurement of 354 healthcare workers were obtained for determining the face area, which is shown in the distribution graph in FIG. 10. The mean face area is found to be 150.22 cm ², with a standard deviation of 16.54 cm ². Based on the data, the healthcare workers are separated into three groups, namely (1) small face size; (2) medium face size; and (3) large face size.

FIG. 11 is a table showing the fit test passing rate of the respirator 100 comparing with a conventional 3-panel model respirator (or known as “horizontal fold-flat respirator” ) , and the fit test passing rate of the respirator 100B comparing with a conventional cup-shaped model respirator (or known as “vertical fold-flat respirator” ) . On all three groups of healthcare workers, the fit test passing rate are significantly higher than the conventional models. In particular, the passing rate of the respirator 100B in cup-shaped configuration has generally very high (80.6%-94.1%) across the healthcare workers of all face sizes. In summary, with applying the same testing protocol on Chinese healthcare workers, the

respirators

100, 100B of the present disclosure have better fit rate than that of other conventional respirators, particularly for individuals with a small and medium face size. This demonstrates the improvements on the fit test results after employing the embodiments of the present disclosure. Similarly, further testing on second group of Chinese healthcare workers was performed using the

respirator

100, 100B of the present disclosure. The upper and

lower strap

210, 220 are adjusted to the optimal lengths most suitable for the user using the markings 240 to improve the fit test results. Affirmative results of 87.5%and 88.5%were obtained, which endorses the positive impact achieved by the present disclosure.

Another aspect of assessing the performance of the respirator 100 is on the usability. This is a subjective analysis and a user survey was conducted. The results are summarized in FIGS. 12-13. The usability of the respirator 100 is comparable with the some N95 with earloop with clips design in a 20-minute usage. However, for donning of 2-3 hours, which is a normal working pattern, the shortcomings of earloop with clips design significantly demonstrated on item 1.3 (feeling tightness) , item 1.7 (discomfort on ear lobe) , item 1.8 (can use in long duration) , item 1.9 (lowering my working efficiency) , and item 1.11 (overall comfort) . Therefore, the respirator 100 of the present disclosure out-performs the counterpart in usability.

As illustrated above, the respirator 100 of the present disclosure offers a low-cost improvement to the conventional face masks that can significantly improve the passing rate of the quantitative fit testing for wearers with diverse facial anthropometry and head sizes. The respirator 100 is designed for achieving the standard for clinical use, with a high level of protection against any aerosol transmissions.

This illustrates the fundamental structure and mechanism of the respirator in accordance with the present disclosure. It is apparent that the present disclosure may be embodied in other types of face mask and protective mask without departing from the spirit or essential characteristics thereof. The present embodiment is, therefore, to be considered in all respects as illustrative and not restrictive. The scope of the disclosure is indicated by the appended claims rather than by the preceding description, and all changes that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

List of References

There follows a list of references that are occasionally cited in the specification. Each of the disclosures of these references is incorporated by reference herein in its entirety.

[1] Charm, C.Y.C., Lam, S.C., et al. (2010) . The fitness of N95 respirators among undergraduate Chinese nursing students in Hong Kong. International Journal of Infectious Diseases, 14 (suppl 2) , S8.

[2] Lam, S.C., Lee, J.K.L., Lee, L.Y.K., Wong, K.F., &Lee, C.N.Y. (2011) , Respiratory protection by respirators: The predictive value of user-seal-check for the fit determination in healthcare settings. Infection Control and Hospital Epidemiology, 32 (4) , 402-403. doi: 10.1086/659151

[3] Lam, S.C., Lee, J.K.L., Yau, S.Y., &Charm, C. Y. C. (2011) , Sensitivity and specificity of the user-seal-check in determining the fit of N95 respirators. Journal of Hospital Infection, 77, 252-256. doi: 10.1016/j. jhin. 2010.09.034

[4] Lam, S.C., Lui, A.K.F., Lee, J.K.L., Lee, L.Y.K., Wong, K.F., &Lee, C.N.Y. (2012) , Testing of the sensitivity and specificity of the user-seal-check procedure on “gross leakage” of N95 respirators. International Journal of Infectious Diseases, 16S, e377. doi: 10.1016/j. ijid. 2012.05.487.

[5] Lam, S.C., Lui, A.K., Lee, L.Y., Lee, J.K., Wong, K.F., &Lee, C.N. (2016) , Evaluation of the user-seal-check on gross leakage detection of three different designs of N95 filtering facepiece respirators. American Journal of Infection Control, 44, 579-86.

[6] Suen, L.L., Guo, Y.P., Ho, S.S., Au-Yeung, C.H., &Lam, S.C. (2020) , Comparing mask fit and usability of traditional and nanofibre N95 filtering facepiece respirators before and after nursing procedures. Journal of Hospital Infection, 104 (3) , 336-343. doi: 10.1016/j. jhin. 2019.09.014.

Claims

A respirator, comprising:

a mask body adapted to fit over a mouth and a nose of a wearer;

an upper strap adjustably attachable to the mask body by threading through at least one upper anchor structure; and

a lower strap adjustably attachable to the mask body by threading through at least one lower anchor structure;

wherein:

each of the upper strap and the lower strap comprises markings for indicating at least one upper position on the upper strap and at least one lower position on the lower strap; and

the upper position defines a first length of the upper strap and the lower position defines a second length of the lower strap that the respirator fits to the wearer with increased consistency when the upper and lower straps are pulled against the upper and lower anchor structures and stretched over the wearer’s head.
The respirator of claim 1, wherein the mask body comprises a breathable zone, the upper and lower anchor structures are provided on perimeter regions of the mask body outside the breathable zone.
The respirator of claim 2, wherein the perimeter regions comprise one or more attachments.
The respirator of claim 1, wherein the upper and lower anchor structures are selected from the group consisting of staples, clips, pins, fasteners, and other attachment means.
The respirator of claim 1, wherein the upper and lower anchor structures and the mask body are formed integrally.
The respirator of claim 1, wherein the upper and lower straps are made of polyisoprene for providing a tension force to keep the respirator in position without slipping off.
The respirator of claim 1, wherein the upper and lower straps are made of rubbers selected from the group consisting of natural Gutta-percha and synthesized trans-1, 4-polyisoprenes; natural rubber and synthesized cis-1, 4-polyisoprene; poly-cis-isoprene; and other polymers and petroleum-based monomers.
The respirator of claim 1, wherein the upper and lower straps are attachable to a front side of the mask body.
The respirator of claim 1, wherein each of the upper and lower straps has a first end welded to the mask body and a second end adjustably attachable to the mask body.
The respirator of claim 1, wherein:

the upper strap has a first end adjustably attachable to the mask body through a first upper anchor structure, and a second end adjustably attachable to the mask body through a second upper anchor structure, and

the lower strap has a third end adjustably attachable to the mask body through a first lower anchor structure, and a fourth end adjustably attachable to the mask body through a second lower anchor structure.
The respirator of claim 10, wherein the markings comprise left markings provided on the first end and the third end, and right markings provided on the second end and the fourth end.
The respirator of claim 1, wherein the markings are evenly spaced across a longitudinal length of the upper and lower straps for providing visual indications of the upper position and the lower position.
The respirator of claim 1, wherein the markings are scribed, printed, engraved, stamped, or embossed on the upper and lower straps.
A non-reusable respirator characterized in that passing rate of quantitative fit testing is increased for wearers with diverse facial anthropometry and head sizes, the non-reusable respirator comprising:

a mask body adapted to fit over a mouth and a nose of the wearer, wherein the mask body comprises one or more spunbond polypropylene fabrics and one or more meltblown polypropylene filter layers;

an upper strap adjustably attachable to the mask body by threading through at least one upper anchor structure; and

a lower strap adjustably attachable to the mask body by threading through at least one lower anchor structure;

wherein:

each of the upper strap and the lower strap comprises markings for indicating at least one upper position on the upper strap and at least one lower position on the lower strap; and

the upper position defines a first length of the upper strap and the lower position defines a second length of the lower strap that the non-reusable respirator fits to the wearer with increased consistency when the upper and lower straps are pulled against the upper and lower anchor structures and stretched over the wearer’s head.
The non-reusable respirator of claim 14, wherein the mask body is in a 3-panel configuration or a cup-shaped configuration.
The non-reusable respirator of claim 14, wherein the upper and lower anchor structures and the mask body are formed integrally.
The non-reusable respirator of claim 14, wherein the upper and lower anchor structures are selected from the group consisting of staples, clips, pins, fasteners, and other attachment means.
The non-reusable respirator of claim 14, wherein the markings are evenly spaced across a longitudinal length of the upper and lower straps for providing visual indications of the upper position and the lower position.
The non-reusable respirator of claim 18, wherein the markings are scribed, printed, engraved, stamped, or embossed on the upper and lower straps.
The non-reusable respirator of claim 14, wherein the upper and lower straps are made of polyisoprene for providing a tension force to keep the non-reusable respirator in position without slipping off.