Wildland firefighter protective shirt

Abstract

A wildland firefighter (WLFF) protection shirt is provided that includes outer portions of the first material and a second internal portion formed of a second material. The second internal portions are placed to maintain air gaps while worn by a firefighter. A method of protecting a firefighter includes the placement of a protection shirt having an outer portion and sleeves around a torso of the firefighter and with arms of the firefighter inserted through the sleeves thereof. Air gaps are maintained between at least one of neck, shoulders, upper torso or wrists of the firefighter and a proximal portion of the outer portion of the shirt.

Description

1 WILDLAND FIREFIGHTER PROTECTIVE SHIRT FIELD OF THE INVENTION

[0001] This application is a non-provisional application that claims priority benefit of US Provisional Application Serial Number 63 / 754,107; filed February 5, 2024; the contents of which are hereby incorporated by reference. FIELD OF THE INVENTION

[0002] The present invention relates to a protective shirt, and more particularly, to wildland firefighter protective shirt that includes and maintains air gaps on burn prone wearer body areas (e.g., neck, shoulders, upper torso of back and front, and wrists) to improve the thermal protection properties of the garment in these typically problematic areas. BACKGROUND OF THE INVENTION

[0003] Wildfires cause severe damage to natural resources, ecosystems, and communities around the world every year. The number of wildland fires has substantially increased during the last several decades (Tyukavina et al., 2022). There was a record-breaking wildfire season with approximately 15 million hectares burned across Canada in 2023 (Erni et al., 2024; Jain et al., 2024). There is a need for thousands of wildland firefighters to control these threats. Wildland firefighters risk their health to prevent such fires from spreading by performing fatiguing activities that often lead to thermal strain (e.g., felling trees, removing brush, and digging barrier trenches) while facing hot weather, smoke, and open flame (Budd et al., 1997; Carballo-Leyenda et al., 2019; Reinhardt & Ottmar, 2004; Smith et al., 2013; Withen, 2015). The potential occupational hazards CA 3300834 Date reçue / Received date 2026-02-04 2 include exposure to high radiant heat, ultraviolet radiation, and contact with sharp objects (chainsaws and other tools). Work shifts can last up to 24 hours (Alberta ALIS, 2021). Although wildland firefighters are mostly exposed to radiant heat from the fire, they also can be engulfed in flames due to rapidly spreading fires and shifting wind directions (Butler, 2014; Dale et al., 2000). Additionally, wildland firefighters experience very high rates of metabolic heat production and may perspire heavily because of the natural cooling mechanisms of the human body (Das & Alagirusamy, 2010a). The thermal stress from the environmental conditions, and work activities can lead to physiological strain. There is also a persistent risk to wildland firefighters of developing cardiovascular disease or lung cancer (Navarro et al., 2019).

[0004] Wildland firefighters’ protective clothing is significantly different from the bulky protective gear of structural firefighters, that is typically multilayer jacket and pants (NFPA, 2018). According to 1) Canadian standard, CAN / CGSB-155.22 Fireline Workwear for Wildland Firefighters, and 2) US standard, NFPA 1977 Standard on Protective Clothing and Equipment for Wildland Firefighting, there are two options for wildland firefighters’ protective clothing: a one-piece garment (coverall) or a two-piece garment (jacket / shirt and pants). The protective garment is intended to provide protection against high thermal exposure as well as short-term engulfment by flames, while still allowing for ventilation and evaporation of perspiration to minimize physiological strain (Crown et al., 2002; Lawson et al., 2004). Essential requirements for the materials used in the wildland firefighter protective garments illustratively include flame- and heat-resistance, durability, including tearing and tensile strength of textile material and seams, and abrasion resistance are specified in regulatory standards in North America. Wildland firefighters’ protective clothing is generally worn on top of undergarments and is thus referred to as a two-layer CA 3300834 Date reçue / Received date 2026-02-04 3 fabric system since there are two layers of fabric between the skin and the hazardous environment. The outer garment which is a flame resistant material and undergarments (t-shirt and briefs) which are made of natural fibres or fibres with melt-resistant properties (Canadian General Standards Board [CGSB], 2014; Petrilli & Ackerman, 2008).

[0005] Air gaps play an essential role in all types of thermal protective clothing as the layer of air provides thermal insulation and helps prevent skin burn injury. According to previous work, it has been shown that the best performance of thermal insulation occurs when the air gap is approximately 7 mm thick (Song, 2007; He et al., 2012). Other researchers, who tested protective clothing in a simulated flash fire / instrumented manikin system that closely represented a life-like scenario of short-time full body engulfment in flames, have shown that personal protective clothing worn by wildland firefighters is not able to protect some areas of the body in direct contact with the garment fabric (e.g., neck, shoulders, upper torso of back and front, and wrists) (Rucker et al., 2000). They found that these body areas showed more burn injuries than areas where an air gap between the fabric and skin was maintained.

[0006] Normally, it is not possible to maintain an evenly distributed air gap throughout all areas of a protective garment. The size of the air gap depends on the fit of the garment and is determined during product development. In all garment designs, there are areas where the fabric rests on the human body. The shoulders, upper front and upper back torso are among these body areas of close contact with the garment. Because an air gap cannot be maintained, the protection that can be provided is limited. Maintaining air gaps in these areas through garment design has not been previously addressed. CA 3300834 Date reçue / Received date 2026-02-04 4

[0007] Thus, there exists a need for wildland firefighters’ protective clothing that includes and maintains air gaps on burn prone areas (e.g., neck, shoulders, upper torso of back and front, and wrists) to improve the thermal protection properties of the garment in these typically problematic areas. SUMMARY OF THE INVENTION

[0008] A wildland firefighter (WLFF) protection shirt is provided that includes a bodice portion formed of a first material, a first yoke portion formed of the first material and a second yoke portion formed of a second material, the second yoke portion being smaller than the first yoke portion. The first yoke portion attached to a top edge of the bodice portion. A first collar portion formed of the first material and a second collar portion formed of the second material, the second collar portion being smaller than the first collar portion. The first collar portion attached to a collar section of the first yoke portion. Opposing sleeve formed of the first material and attached to a right and left sides of the first yoke portion and to the bodice portion. Opposing first right and left side cuff portions formed of the first material and second cuff portions formed of the second material, the second cuff portions being smaller than the first cuff portions, the first cuff portions attached to a free end of the opposing sleeves.

[0009] A method of protecting a firefighter includes the placement of a protection shirt having an outer portion and sleeves around a torso of the firefighter and with arms of the firefighter inserted through the sleeves thereof. Air gaps are maintained between at least one of neck, shoulders, upper torso or wrists of the firefighter and a proximal portion of the outer portion of the shirt. CA 3300834 Date reçue / Received date 2026-02-04 5 BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The subject matter that is regarded as the invention is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other objects, features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:

[0011] FIGS. 1A and 1B show a conventional, prior art wildland firefighter’s shirt (control shirt): (FIG. 1A) front view, and (FIG. 1B) back view;

[0012] FIGS. 2A and 2B show annotated drawings of the conventional, prior art control shirt design: (FIG. 2A) front view, (FIG. 2B) back view;

[0013] FIG. 3A and 3B show annotated drawings of a shirt according to certain embodiments of the present invention: (FIG. 3A) front view, (FIG. 3B) back view;

[0014] FIGS. 4A and 4B show a simulation of the conventional, prior art shirt fit in CLO renderings: (FIG. 4A) front view, and (FIG. 4B) back view;

[0015] FIG. 5 shows a technical drawing of the yoke joining the front and back yokes with a portion of the sleeve cap according to certain embodiments of the present invention;

[0016] FIG. 6 shows a top view of modified yoke in a simulated shirt according to embodiments of the present invention;

[0017] FIGS. 7A and 7B show a simulation of a shirt according to embodiments of the present invention fit in CLO: (FIG. 7A) front view, and (FIG. 7B) back view;

[0018] FIGS. 8A and 8B show a constructed wildland firefighter’s a shirt according to embodiments of the present invention: (FIG. 8A) front view, and (FIG. 8B) back view; CA 3300834 Date reçue / Received date 2026-02-04 6

[0019] FIG. 9 shows a top view of modified yoke in constructed a shirt according to certain embodiments of the present invention;

[0020] FIG. 10 shows a schematic drawing of stand collar and yoke construction with incorporated layer of three-dimensional warp-knitted fabric according to certain embodiments of the present invention;

[0021] FIG. 11 shows a schematical drawing of cuff construction with incorporated layer of three-dimensional warp-knitted fabric according to certain embodiments of the present invention;

[0022] FIG. 12 shows pattern pieces of a shirt according to embodiments of the present invention; and

[0023] FIGS. 13A-13F shows detailed views of a shirt according to embodiments of the present invention: (FIG. 13A) yoke back, (FIG. 13B) yoke inner side, (FIG. 13C) collar with front closure, (FIG. 13D) patch pocket with flap, and sleeve cuff (FIG. 13E) closed (FIG. 13F) open. DESCRIPTION OF THE INVENTION

[0024] The present invention has utility as a wildland firefighters’ protective clothing that includes and maintains air gaps on burn prone areas (e.g., neck, shoulders, upper torso of back and front, and wrists) to improve the thermal protection properties of the garment in these typically problematic areas.

[0025] The present invention will now be described with reference to the following embodiments. As is apparent by these descriptions, this invention can be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully CA 3300834 Date reçue / Received date 2026-02-04 7 convey the scope of the invention to those skilled in the art. For example, features illustrated with respect to one embodiment can be incorporated into other embodiments, and features illustrated with respect to a particular embodiment may be deleted from the embodiment. In addition, numerous variations and additions to the embodiments suggested herein will be apparent to those skilled in the art in light of the instant disclosure, which do not depart from the instant invention. Hence, the following specification is intended to illustrate some particular embodiments of the invention, and not to exhaustively specify all permutations, combinations, and variations thereof.

[0026] The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Unless indicated otherwise, explicitly or by context, the following terms are used herein as set forth below.

[0027] As used herein, the singular forms “a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, CA 3300834 Date reçue / Received date 2026-02-04 8 unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.

[0028] When an element or layer is referred to as being “on,” “engaged to,” “connected to,” or “coupled to” another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to,” “directly connected to,” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items.

[0029] Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.

[0030] Spatially relative terms, such as “inner,” “outer,” “beneath,” “below,” “lower,” “above,” “upper,” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. Spatially CA 3300834 Date reçue / Received date 2026-02-04 9 relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the example term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

[0031] It is to be understood that in instances where a range of values are provided that the range is intended to encompass not only the end point values of the range but also intermediate values of the range as explicitly being included within the range and varying by the last significant figure of the range. By way of example, a recited range of from 1 to 4 is intended to include 1-2, 1-3, 2-4, 3-4, and 1-4.

[0032] The present invention provides a wildland firefighters (WLFF) shirt that improves thermal protection by incorporating a flame-resistant, lightweight, and porous 3D warp-knitted fabric in areas of contact with a wearer’s skin, i.e., burn prone areas, of typical WLFF protective shirts while also maintaining the comfort properties of the WLFF garment, including thermal and evaporative resistance, and air permeability. According to embodiments, the WLFF protective shirt incorporates three-dimensional warp-knitted fabric in areas of the garment that are in contact with the skin and prone to burn injuries.

[0033] Protective clothing system design for wildland firefighters in North America should meet the minimal requirements outlined in CAN / CGSB-155.22 and NFPA 1977 standards (CGSB, 2014; NFPA, 2016). According to these standards, protective clothing could be two-piece garment (shirt or jacket, and pants), or one-piece garment (coverall). Collars should remain upright after CA 3300834 Date reçue / Received date 2026-02-04 10 being extended to the vertical position. Sleeves should not have turn-up cuffs. The cuffs should have a closure that can provide tight and secure fit around the wrists. All pockets that open to the exterior should have a cover (flaps) of other closure system. This requirement does not apply to the front waist pockets. Pass through openings must have a means of fastening them in a closed position. In case of one-piece garments, the closure should be continuous from the top of the crotch area to the top of the garment in the neck area. Closure systems and hardware cannot come into direct contact with body.

[0034] Additionally, NFPA 1977 specifies that garment hardware finish must be free of any rough or sharp edges (NFPA, 2016). All threads used in garment construction should be made of inherently flame-resistant fibres. Visibility markings are applied on the exterior of the garments and should provide 360-degree visibility of the wearer.

[0035] CAN / CGSB-155.22 specifies that the use of high visibility trim in wildland firefighters’ protective clothing is optional (CGSB, 2014). Sleeve vents are prohibited. In addition, any garment worn under the protective garment should have melt-resistant properties. Thus, some synthetic and synthetic blends are not suitable to be used as a base layer.

[0036] According to embodiments, the inventive WLFF shirt provides thermal protection to the upper front, upper back torso, upper arms areas, wrists, and neck. The inventive WLFF shirt is a one-piece garment that has additional thermal protection provided through the localized incorporation of a three-dimensional warp-knitted fabric into the garment. Also, the inventive WLFF shirt is an invention for the wildland firefighters’ protective clothing ensemble. The three-dimensional warp-knitted fabric used in the inventive shirt design is a spacer textile disclosed by Keitch (2014) in European patent No. 2707529B1, assigned to Heathcoat Fabrics Limited, CA 3300834 Date reçue / Received date 2026-02-04 11 disclosed spacer textiles. As Bibeau (2016) and Keitch (2014) (detailed below) specify, the monofilament yarn made of PEEK fibre in the spacer fabrics provides good compression resilience. Thus, this fabric can entrap a large quantity of air and act as a thermal barrier. Additionally, it provides cushioning in the shoulder area when wildland firefighters carry heavy loads that cause high compression of the shoulder area. The invention of the WLFF shirt design with the aforementioned features has never before been developed as part of the wildland firefighters’ protective clothing ensemble. The shirt design currently worn by wildland firefighters in Alberta is the starting point for the design of the inventive garment. The current shirt is the control shirt in this research and the design of this shirt is described below.

[0037] In Keitch (2014) generally, spacer textiles are produced from polyester or nylon on raschel warp-knitting machines. But this invention has two layers of fabric, knitted from meta-aramid yarns. Both fabric layers are connected by relatively thick (0.05 to 0.25 mm diameter) monofilament polyetheretherketone (PEEK) yarn. These monofilaments provide the three-dimensional quality to the textile. The thickness range can be varied, and it depends on the final use. These fabric structures can be highly porous and lightweight. At the same time, they provide sufficient resilience without being too stiff in use. The inherently flame-resistant fibre content of this fabric along with entrapped air in the fabric allows this invention to be implemented as a thermal barrier in protective clothing.

[0038] Bibeau (2016) in Canadian patent No. 2919104C, assigned to Logistik Unicorp Inc., disclosed an insulating garment for firefighters’ bunker gear. The invention is worn under the main outer shell of firefighters and serves as a moisture repellent and thermal barrier. This garment is made of fabric similar to the one that was disclosed by Flay et al. (2007) in U.S. patent No. CA 3300834 Date reçue / Received date 2026-02-04 12 2007 / 0284558A1 and Keitch (2014) in European patent No. 2707529B1. It also has two layers of fireresistant fabric that are interconnected by a yarn and laminated with a moisture repellent breathable membrane. The method of connecting the two fabric layers is similar to the construction of a double-weave velvet, but without the separation of the two fabrics after weaving. Flay et al. (2007) failed to identify the overall essential function of the connecting yarn. However, Bibeau (2016) similarly to Keitch (2014) specified that this yarn should be a monofilament with good compression resilience, possibly made of polyphenylene sulphate (PPS), polyetheretherketone (PEEK), or polyetherimide. Bibeau (2016) emphasized that normally firefighters carry heavy loads that cause high compression of the shoulder area. This leads to compression of the thermal barrier and loss of its thermal insulation properties. Therefore, the resilient monofilament in the new thermal barrier fabric developed by Bibeau (2016) can resist compression, entrap a large quantity of air and can potentially improve the properties of the thermal liners.

[0039] The inventive WLFF shirt design is based on the design of a conventional, prior art shirt (style GS. 640) Winner Garment Industries Ltd., as shown in prior art FIG. 1. Reproduction of this shirt is synonymously referred to herein as the control shirt. A detailed description of the control shirt design is provided below.

[0040] The control shirt is the protective shirt for male wildland firefighters, as shown in FIG. 2A and 2B. The shirt has a regular fit and low hip length. The front has a placket closure with sewn-on stainless steel hidden snaps. Two patch pockets with flaps and flame-resistant hook-and-loop closure are attached to the shirt front pieces in the chest area. The back of the shirt has two action pleats and a double shirt yoke. The stand collar has a flame-resistant hook-and-loop closure. Each of the two long sleeves are set-in and consist of one-piece of fabric with a single lengthwise CA 3300834 Date reçue / Received date 2026-02-04 13 seam and continuous sleeve placket. There are two pleats in the sleeve at the cuff. The cuff has a flame-resistant hook-and-loop closure. The double top stitched seam (two parallel straight stitches) is applied on the edge of the pocket, pocket flap, shoulder, yoke, and armhole seams. A single top-stitched seam (one straight stitch) is applied on the edges of the collar, cuffs, and bottom hem. The shirt is made of plain weave NOMEX® IIIA fabric. Segmented adhesive reflective trim, 3MTM SCOTCHLITETM, is applied horizontally at the chest level of the shirt front and back, and on each sleeve slightly below the elbow.

[0041] The inventive WLFF shirt is a wildland firefighter’s protective shirt with incorporated highly porous, lightweight, compression-resilient, and flame-resistant three-dimensional raschel warp-knitted fabric in specific areas for improvement of the thermal protection performance and comfort properties of the garment. Three-dimensional warp-knitted fabric is incorporated in areas of the upper front and back torso, upper arms, shoulders, neck, and wrists. These areas normally do not have an air gap between the garment and body. As a result, these areas of the body do not have sufficient thermal protection and are prone to skin burn injury in short-duration flame engulfment tests. The three-dimensional warp-knitted fabric entraps still air and impedes thermal energy transfer through the garment system while increasing air permeability and improving thermal comfort. Thus, the protective shirt provides sufficient thermal protection to prevent skin burn injury in specific areas of the garment. Additionally, the resiliency of the three-dimensional warp-knitted fabric provides good resistance to compression and cushioning in the shoulder area when wildland firefighters carry heavy loads on their shoulders.

[0042] The inventive WLFF shirt is a protective shirt for male wildland firefighters As shown in FIGS. 3A and 3B, the shirt is shown generally at 10 has a regular fit and low hip length in some CA 3300834 Date reçue / Received date 2026-02-04 14 embodiments. It is appreciated that other fits and lengths are readily provided without departing from the inventive concept. The shirt 10 has a yoke 12 that covers the shoulders, upper front, upper back and upper arm areas of a wearer. The yoke 12 in some embodiments includes two pieces (14, 14’) that are sewn together by a centre back seam 16. Each left and right piece combines the front and back yoke with a portion of the sleeve cap 18. The shirt front 20 has a placket closure 22 with stainless steel sewn-on hidden snaps or other conventional fasteners (not shown). Patch pockets 24 and flaps 26 typically are provided with flame-resistant conventional fasteners (not shown) such as hook-and-loop closures. Patch pockets 24 and flaps 26 typically are shown attached to the shirt front 20 in the chest area below the yoke seam 28, but it should be appreciated that the inclusion and positioning thereof is a matter of design choice. A shirt back 30 of a shirt 10 in some inventive embodiments has two action pleats 32, 32’ in the yoke seam 28. A stand collar 34 of the shirt 10 has a flame-resistant hook-and-loop conventional fasteners (not shown) such as hook-and-loop closures. The sleeves 36, 36’ as shown are composed of three pieces, including the upper sleeve that is attached to the extended yoke above the elbow level, the front under-sleeve, and the back undersleeve. It is appreciated that other sleeve constructs are feasible without departing from the present invention and illustratively include two and four piece constructs. Each of the two sleeves 36, 36’as shown has an in-seam placket at the cuff location 18, and two pleats on the back under-sleeve at the cuff. The cuff in some inventive embodiments has a flame-resistant fastener. While the type of stitching used is often a matter of design choice, in certain inventive embodiments, double top-stitched seams formed by two parallel straight stitches is placed at the edge of the pockets, and pocket flaps to provide added durability. A single top-stitched seam formed by one straight stitch is applied on the edge of the bottom hem. The shirt 10 is readily CA 3300834 Date reçue / Received date 2026-02-04 15 formed from a variety of base materials, these materials illustratively include plain weave NOMEX® IIIA (93 wt. % meta-aramind, 5 wt. % para-aramid, 2 wt. % antistatic fiber) fabric, TECASAFE® Plus (cellulosic / aramid blend), various blends of meta-aramid, para-aramid, and Lenzing FR, and combinations thereof. The base material supplemented with flame-resistant three-dimensional warp-knitted fabric 40 is placed to maintain airgaps between a user and the exterior of the shirt 10. Typical air gaps maintained by the present invention between the outer layer of the WLFF and the inner most region that is defined herein as wearer anatomy but practically are undergarments typically ranges between 0.05 and 8 millimeters. The position of the flame-resistant three-dimensional warp-knitted fabric 40 is best seen with reference to other drawings that include FIGS. 6, 10, and 11. These three-dimensional warp-knitted fabrics 40 illustratively include PET / aramid nonwoven layers and warp‑knitted spacer cores, SPACETEC® (3D spacer fabric, engineered with two outer fabric layers connected by monofilament spacer yarns that create a breathable air cushion between the two outer fabric layers), modacrylic, treated polyester, aramid fiber layers with cores of materials such as polyurethane; and combinations thereof. L Hahn et al. 3D Textiles Based on Warp Knitted Fabrics: A Review. Materials. 2023; 16(10):3680. In some inventive embodiments, the outer layers of the yoke 12, collar 34, or sleeve cuffs 18 were stitched together in evenly spaced parallel lines to a layer of three-dimensional warp-knitted fabric. Segmented adhesive reflective trim, 38 is applied horizontally at the chest level of the shirt front and back, and on each sleeve slightly below the elbow, as shown in FIGS. 3A and 3B. Reflective trim operative herein illustratively includes 3M SCOTCHLITETM (retroreflective glass beads) products such as 5687 Series: fluorescent lime-yellow, 5686 Series fluorescent red-orange color. CA 3300834 Date reçue / Received date 2026-02-04 16 5535 material, ORALITE® GP851S Brilliance metalized prismatic segmented trim, or a combination thereof.

[0043] Development of prototype shirt patterns is conducted in CLO software (a 3D fashion design software program creating virtual, true-to life garment visualization). The software utilization requires several steps, such as adjustment of simulated mannequin size, development of pattern pieces of the control shirt, manipulating existing pattern pieces of the control shirt to develop new pattern pieces of the prototype shirt and garment fit simulation.

[0044] Prior to any pattern development, the simulated mannequin (avatar) was created in the CLO software and accurately adjusted to be the same dimensions as the flash fire instrumented manikin used for testing. These dimensions included a height of 177 cm, chest circumference of 101 cm, waist of 85 cm and hip of 99.5 cm. The CLO software allows for working in two windows (2D and 3D) simultaneously. The 2D window allows for flat pattern pieces to be developed, edited, and manipulated. The three-dimensional window is for garment seam application and fitting simulation on the avatar. As a result, the software enables the visualization of the final garment fit and allows for pattern adjustments without sewing multiple mock-up garments.

[0045] Once the size of the simulated mannequin was adjusted, the next step was to develop pattern pieces of the control shirt. The control wildland firefighters’ protective shirt was measured and almost identical pattern pieces were developed in the CLO software. The pattern pieces included the shirt front (2), back (1), set-in sleeve (2), back yoke (2), cuff (4), collar (2), patch pocket (2), pocket flap (4) and front placket (2). The simulated garment and mock-up garment showed a very good fit on the avatar and manikin, meaning there was no excess material forming folds or improper drape or restrictions on the body. Only the stand collar pattern was slightly CA 3300834 Date reçue / Received date 2026-02-04 17 changed to ensure a tighter fit of the collar to the neck. Once all these steps were competed, the pattern pieces were ready to use for the prototype shirt development, as shown in FIG. 4A and 4B.

[0046] The new pattern pieces of the inventive shirt were developed by manipulating and editing previously developed pattern pieces for the control shirt. The prototype shirt pattern design included editing of the back yoke, front, back and sleeve patterns, as shown in FIG. 5 and correspond to reference numeral provided with respect to FIGS. 3A and 3B. The back yoke was lowered by 5.5 cm compared to the control shirt to cover most of the upper back area that has no air gap between the garment and skin. A front yoke was also created to cover most of the front upper torso area that also has no air gap. The front, back, and sleeves of the control shirt were joined by the shoulder, armhole, and sleeve cap seams. The bottom seams of the front and back yokes were extended throughout the sleeve. Thus, the sleeve was divided into three pattern pieces including back undersleeve, upper-sleeve, and front under-sleeve. The part of the upper-sleeve that covers the upper arm area was cut and joined with the modified back and front yoke. As a result, a one-piece yoke was developed for each side of the shirt (left and right) that seamlessly covers the upper front and back torso and the upper arm area (shaded). This pattern manipulation allowed the incorporation of the three-dimensional warp-knitted fabric 40 into a modified yoke that covers the areas (excluding wrist and neck areas) that are prone to burn injuries in short-duration flame-engulfment test, as shown in FIG. 6. The three-dimensional warp-knitted fabric 40 was separately incorporated into the collar and cuffs, as best seen in FIGS. 10 and 11. Specifically, the three-dimensional warp-knitted fabric 40 in the cuffs 18 is best seen in FIG. 11 where like reference numerals have the meanings associated with the aforementioned drawings. Smaller-sized pattern pieces for the yoke, collar, and cuffs were developed specifically for the three-dimensional warp- CA 3300834 Date reçue / Received date 2026-02-04 18 knitted fabric. In this way, the extra fabric was not included in the construction seams of the shirt. Instead, it was quilted together with the outer fabric.

[0047] Overall, the prototype shirt contained pattern pieces for the front (2), back (1), upper-sleeve (2), front under-sleeve (2), back under-sleeve (2), yoke (2), cuff (4), collar (2), patch pocket (2), pocket flap (4), and front placket (2). The simulated garment showed excellent fit on the avatar, as shown in FIG. 7.

[0048] The construction of the inventive WLFF shirt does not require any specialized equipment for special purpose seams (e.g. welded seams). A two-thread lockstitch sewing machine and a four-thread overlock sewing machine were used for the prototype construction. All types of seams and stitches in the prototype shirt construction were applied in accordance with the ASTM D 6193 standard (ASTM, 2020e). The garment mock-up fitting, and prototype shirt construction process are presented below.

[0049] As described previously, the 3D simulation of the inventive shirt in CLO software demonstrated an overall good fit of the garment. However, some fabric properties, specifically fabric stiffness, were not accurately visualized in the software. Thus, a mock-up garment made from a fabric with similar thickness and stiffness to the OL fabric was sewn before the final construction of the prototype shirt. The mock-up garment showed excellent fit, meaning there was no excess material forming folds or improper drape or restrictions on the body and no further adjustments were needed before the final prototype shirt was constructed.

[0050] FIG. 8 shows the front and back views of a fully constructed inventive shirt. The materials used in the garment construction included NOMEX® IIIA fabric used for the outer layer, flame-resistant three-dimensional warp-knitted fabric SPACETEC®, flame-resistant hook-and- CA 3300834 Date reçue / Received date 2026-02-04 19 loop fastener (50 mm wide strip), segmented adhesive reflective trim (50 mm wide strip, 3MTM SCOTCHLITETM), stainless steel sew-on snaps, and aramid threads. Additional information regarding the material consumption in a specific embodiment is provided in Table 1. The pattern pieces of the inventive shirt are shown in FIG. 12.

[0051] Table 1. Material

[0052] The construction sequence includes preparing the separate pieces of yoke, front, back, cuffs, and collar, and joining all prepared pieces together. The full construction sequence, including the types of seams and the stitches used, is provided in Table 2.

[0053] Table 2. Inventive shirt construction sequence. CA 3300834 Date reçue / Received date 2026-02-04 20 CA 3300834 Date reçue / Received date 2026-02-04 21 CA 3300834 Date reçue / Received date 2026-02-04 22 CA 3300834 Date reçue / Received date 2026-02-04 23 CA 3300834 Date reçue / Received date 2026-02-04 24 CA 3300834 Date reçue / Received date 2026-02-04 25 CA 3300834 Date reçue / Received date 2026-02-04 26 CA 3300834 Date reçue / Received date 2026-02-04 27 CA 3300834 Date reçue / Received date 2026-02-04 28 CA 3300834 Date reçue / Received date 2026-02-04 29 CA 3300834 Date reçue / Received date 2026-02-04 30 CA 3300834 Date reçue / Received date 2026-02-04 31 CA 3300834 Date reçue / Received date 2026-02-04 32 CA 3300834 Date reçue / Received date 2026-02-04 33 CA 3300834 Date reçue / Received date 2026-02-04 34 CA 3300834 Date reçue / Received date 2026-02-04 35 CA 3300834 Date reçue / Received date 2026-02-04 36 CA 3300834 Date reçue / Received date 2026-02-04 37 CA 3300834 Date reçue / Received date 2026-02-04 38 CA 3300834 Date reçue / Received date 2026-02-04 39 CA 3300834 Date reçue / Received date 2026-02-04 40 CA 3300834 Date reçue / Received date 2026-02-04 41 CA 3300834 Date reçue / Received date 2026-02-04 42 CA 3300834 Date reçue / Received date 2026-02-04 43 CA 3300834 Date reçue / Received date 2026-02-04 44 CA 3300834 Date reçue / Received date 2026-02-04 45 CA 3300834 Date reçue / Received date 2026-02-04 46 CA 3300834 Date reçue / Received date 2026-02-04 47 CA 3300834 Date reçue / Received date 2026-02-04 48 CA 3300834 Date reçue / Received date 2026-02-04 49 CA 3300834 Date reçue / Received date 2026-02-04 50 CA 3300834 Date reçue / Received date 2026-02-04 51 CA 3300834 Date reçue / Received date 2026-02-04 52 CA 3300834 Date reçue / Received date 2026-02-04 53 CA 3300834 Date reçue / Received date 2026-02-04 54 CA 3300834 Date reçue / Received date 2026-02-04 55 CA 3300834 Date reçue / Received date 2026-02-04 56 CA 3300834 Date reçue / Received date 2026-02-04 57 CA 3300834 Date reçue / Received date 2026-02-04 58 CA 3300834 Date reçue / Received date 2026-02-04 59 CA 3300834 Date reçue / Received date 2026-02-04 60 CA 3300834 Date reçue / Received date 2026-02-04 61 CA 3300834 Date reçue / Received date 2026-02-04 62 CA 3300834 Date reçue / Received date 2026-02-04 63 CA 3300834 Date reçue / Received date 2026-02-04 64

[0054] FIG. 9 shows the top view of the inventive WLFF shirt yoke. As previously described, the yoke has no shoulder seam or armhole-sleeve cap seam. The outer layer of the yoke is quilted together with the three-dimensional warp-knitted fabric. This design solution which joins the front and back yokes along with a portion of the upper-sleeve eliminates any possible seam bulk from sewing two layers of the outer layer fabric with the three-dimensional warp-knitted fabric. It also simplified the garment construction and improved the overall range of motion of this area of the CA 3300834 Date reçue / Received date 2026-02-04 65 garment. Since wildland firefighters carry heavy backpacks on duty, eliminating the seams and providing additional cushioning from the three-dimensional knitted fabric in the shoulder, upper front and back torso areas also improves the physical comfort properties of the garment.

[0055] Construction of the yoke includes attachment of bias binding 42 along the three-dimensional warp-knitted fabric (seam SSaa, LSq; stitch 301) and stitching the outer layer fabric with three-dimensional warp-knitted fabric following evenly spaced 30 mm distant stitch lines (seam SSv; stitch 301). The pattern piece for the three- dimensional warp-knitted fabric is smaller than the piece for the outer layer fabric, so bias binding is attached to compensate for the initial dimensions. This approach allows the exclusion of three-dimensional warp-knitted fabric from any seam allowances and makes the seams thinner and more flexible. FIG. 10 presents schematic drawings of this construction technique and FIG. 13B presents a detailed view of the inner side of the yoke.

[0056] Cuffs and collar construction includes similar operations. Like the yoke construction, the pattern pieces for the three-dimensional warp-knitted fabric of the cuffs and collar are smaller than the pieces for the outer layer fabric. However, these pieces are directly stitched to the outer layer fabric of the cuffs or collar following evenly spaced 30 mm distant parallel lines (seam SSv; stitch 301). Eventually, the three-dimensional warp-knitted fabric is positioned between the outer layer fabric forming the outer and inner surfaces of the cuffs and collar (seam LScg-2; stitch 301). FIG. 11 shows a schematic drawing of this construction technique and FIGS. 13A-13F shows a detailed view of collar and cuff.

[0057] The yoke, collar, and cuffs that are padded with the three-dimensional warp-knitted fabric cover approximately 25% of the whole prototype shirt area. Construction of the shirt front CA 3300834 Date reçue / Received date 2026-02-04 66 includes preparation and attachment of patch pockets and flaps, also attachment of snaps to the front plackets (seam LSbj, LSd-2, SSa-1, SSe-3; stitch 301, 506). The action pleats of the shirt back are pressed and basted before joining all pieces together. The final step was to join all sections of the garment together, serge the edges, and finish the hem (seam SSa-2, EFs; stitch 301, 506).

[0058] The design of the inventive WLFF shirt enhances protection for areas vulnerable to burn injuries—such as the front and back of the upper torso, neck, and cuffs—by integrating three-dimensional warp knitted fabric into the yoke, collar, and cuffs. This fabric is thick, porous, lightweight, and resistant to compression, creating an artificial air gap over these critical areas. Embodiments of the inventive shirt utilize innovative construction techniques to incorporate the three-dimensional warp knitted fabric seamlessly, minimizing bulk at the seams and improving flexibility and usability.

[0059] In this design, the three-dimensional warp knitted fabric lacks seam allowances and is cut slightly smaller than the pattern sizes for the collar, yoke, and cuffs. Only the thin outer and inner layer fabrics include seam allowances and are used in the seams themselves. The three-dimensional warp knitted fabric is positioned securely between the outer and inner layers and is stitched only to the outer layer of the collar and cuffs. Covering the three-dimensional warp knitted fabric with an inner layer prevents direct skin contact with its rough surface, especially at the wrists and neck.

[0060] Since wildland firefighters typically wear a cotton t-shirt, there is no direct skin contact with the three-dimensional warp knitted fabric in the yoke area, removing the need for an inner layer there. The yoke’s construction differs from that of the collar and cuffs: here, the three-dimensional warp knitted fabric is stitched to the outer layer only, with no inner layer. Like the CA 3300834 Date reçue / Received date 2026-02-04 67 collar and cuffs, the yoke’s three-dimensional warp knitted fabric is cut without seam allowances and slightly smaller than the pattern. A separate bias strip, cut from the outer layer fabric, is sewn along the yoke’s curved edges. This bias covers the raw edges of the three-dimensional warp knitted fabric and extends it to match the size of the outer layer, ensuring a clean and finished edge.

[0061] The construction technique developed for the inventive shirt successfully integrates three-dimensional warp knitted fabric in a way that improves its thermal protection while maintaining comfort and mobility. The unique methods of stitching and layering not only create an insulating air gap over vulnerable areas but also prevent direct contact with the rough fabric surface, ensuring wearability. REFERENCES

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[0066] Budd, G.M., Brotherhood, J.R., Hendrie, A.L., Jeffery, S.E., Beasley, F.A., Costin, B.P., Zhien, W., Baker, M.M., Cheney, N.P. and Dawson, M.P.,(1997). Project Aquarius 6. Heat load from exertion, weather, and fire in men suppressing wildland fires. International Journal of Wildland Fire, 7(2), 119-131. https: / / doi.org / 10.1071 / WF9970119

[0067] Canadian General Standards Board (2014). CAN / CGSB –155.22 Fireline Workwear for Wildland Firefighters. Ottawa, ON: Canadian General Standards Board.

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[0069] Crown, E. M., Dale, J. D., & Bitner, E. (2002). A comparative analysis of protocols for measuring heat transmission through flame-resistant materials: capturing the effects of thermal shrinkage. Fire and Materials, 26(4-5), 207-213. https: / / doi.org / 10.1002 / fam.797

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[0072] Erni, S., Wang, X., Swystun, T., Taylor, S. W., Parisien, M. A., Robinne, F. N., Eddy, B., Oliver, J., Armitage, B., & Flannigan, M. D. (2024). Mapping wildfire hazard, vulnerability, and risk to Canadian communities. International Journal of Disaster Risk Reduction, 101, 104221. https: / / doi.org / 10.1016 / j.ijdrr.2023.104221

[0073] Flay, P., Hebert, M., & Bibeau, L. (2007). Fire insulating barrier material for a firefighter protective garment ((U.S. Patent No. 2007 / 0284558A1). U.S. Patent and Trademark Office. https: / / patents.google.com / patent / US20070284558A1 CA 3300834 Date reçue / Received date 2026-02-04 69

[0074] He, S., Huang, D., Qi, Z., Yang, H., Hu, Y., & Zhang, H. (2012). The effect of air gap thickness on heat transfer in firefighters’ protective clothing under conditions of short exposure. Heat Transfer Research, 43(8). https: / / doi.org / 10.1615 / HeatTransRes.2012005913

[0075] Jain, P., Barber, Q. E., Taylor, S., Whitman, E., Acuna, D. C., Boulanger, Y., Chavardès, R., D., Chen, J., Englefield, P., Flannigan, M., Girardin, M., P., Hanes, C.C., Little, J., Morrison, K., Skakun, R., S., Thompson, D., K., Wang, X., & Parisien, M. A. (2024). Canada under fire–drivers and impacts of the record-breaking 2023 wildfire season. ESS Open Archive, 1-44. https: / / doi.org / 10.22541 / essoar.170914412.27504349 / v1

[0076] Keitch, G. (2014). Spacer textile (European patent No. 2707529B1). European Patent Office. https: / / patents.google.com / patent / EP2707529B1

[0077] Lawson, L. K., Crown, E. M., Ackerman, M. Y., & Douglas Dale, J. (2004). Moisture effects in heat transfer through clothing systems for wildland firefighters. International Journal of Occupational Safety and Ergonomics, 10(3), 227–238. https: / / doi.org / 10.1080 / 10803548.2004.11076610

[0078] Navarro, K. M., Kleinman, M. T., Mackay, C. E., Reinhardt, T. E., Balmes, J. R., Broyles, G. A., ... & Domitrovich, J. W. (2019). Wildland firefighter smoke exposure and risk of lung cancer and cardiovascular disease mortality. Environmental Research, 173, 462-468. https: / / doi.org / 10.1016 / j.envres.2019.03.060

[0079] National Fire Protection Association (2016). NFPA 1977 Standard on Protective Clothing and Equipment for Wildland Firefighting. Quincy, MA: National Fire Protection Association. CA 3300834 Date reçue / Received date 2026-02-04 70

[0080] National Fire Protection Association (2018). NFPA 1971 Standard on Protective Clothing Ensembles for Structural Fire Fighting and Proximity Fire Fighting. Quincy, MA: National Fire Protection Association.

[0081] Petrilli, T., & Ackerman, M. (2008). Tests of undergarments exposed to fire. United States Department of Agriculture, Forest Service, Technology & Development Program. https: / / www.fs.usda.gov / t-d / pubs / htmlpubs / htm08512348 / index.htm#:~:text=Laboratory%20tests%20showed%20that%20firefighters,and%20stick%20to%20their%20skin

[0082] Reinhardt, T. E., & Ottmar, R. D. (2004). Baseline measurements of smoke exposure among wildland firefighters. Journal of Occupational and Environmental Hygiene, 1(9), 593–606. https: / / doi.org / 10.1080 / 15459620490490101

[0083] Rucker, M., Anderson, E., & Kangas, A. (2000). Evaluation of standard and prototype protective garments for wildland firefighters. In C. N. Nelson & N. W. Henry (Eds.), Performance of protective clothing: issues and priorities for the 21st century (Vol. 7 STP 1386, pp. 546–556). West Conshohocken, PA: American Society for Testing and Materials. https: / / doi.org / 10.1520 / STP14469S

[0084] Smith, C. J., & Havenith, G. (2011). Body mapping of sweating patterns in male athletes in mild exercise-induced hyperthermia. European Journal of Applied Physiology, 111(7), 1391-1404. https: / / doi.org / 10.1007 / s00421-010-1744-8

[0085] Song, G. (2007). Clothing air gap layers and thermal protective performance in single layer garment. Journal of industrial textiles, 36(3), 193-205. https: / / doi.org / 10.1177 / 1528083707069506 CA 3300834 Date reçue / Received date 2026-02-04 71

[0086] Tyukavina, A., Potapov, P., Hansen, M. C., Pickens, A. H., Stehman, S. V., Turubanova, S., Parker, D., Zalles, V., Lima, A., Kommareddy, I., Song, X., Wang, L., & Harris, N. (2022). Global trends of forest loss due to fire from 2001 to 2019. Frontiers in Remote Sensing, 3, 825190. https: / / doi.org / 10.3389 / frsen.2022.825190

[0087] Withen, P. (2015). Climate change and wildland firefighter health and safety. New Solutions: a Journal of Environmental and Occupational Health Policy, 24(4), 577–584. https: / / doi.org / 10.2190 / NS.24.4.i

[0088] Patent documents and publications mentioned in the specification are indicative of the levels of those skilled in the art to which the invention pertains. These documents and publications are incorporated herein by reference to the same extent as if each individual document or publication is specifically and individually incorporated herein by reference.

[0089] The foregoing description is illustrative of particular embodiments of the invention but is not meant to be a limitation upon the practice thereof. The following claims, including all equivalents thereof, are intended to define the scope of the invention. CA 3300834 Date reçue / Received date 2026-02-04

Claims

72 CLAIMS 1. A wildland firefighter (WLFF) protection shirt comprising: a bodice portion formed of a first material; a first yoke portion formed of the first material and a second yoke portion formed of a second material, the second yoke portion being smaller than the first yoke portion, the first yoke portion attached to a top edge of the bodice portion; a first collar portion formed of the first material and a second collar portion formed of the second material, the second collar portion being smaller than the first collar portion, the first collar portion attached to a collar section of the first yoke portion; a right sleeve formed of the first material and attached to a right side of the first yoke portion and to the bodice portion; a first right side cuff portion formed of the first material and a second right side cuff portion formed of the second material, the second right side cuff portion being smaller than the first right side cuff portion, the first right side cuff portion attached to a free end of the right sleeve; a left sleeve formed of the first material and attached to a left side of the first yoke portion and to the bodice portion; and a first left side cuff portion formed of the first material and a second left side cuff portion formed of the second material, the second left side cuff portion being smaller than the first left side cuff portion, the first left side cuff portion attached to a free end of the left sleeve.

2. The WLFF protection shirt of claim 1 wherein the second yoke portion, the second collar portion, the second right side cuff portion, and the second left side cuff portion do not include any seam allowances. CA 3300834 Date reçue / Received date 2026-02-04 73 3. The WLFF protection shirt of claim 1 wherein the second material is a three-dimensional warp-knitted fabric.

4. The WLFF protection shirt of claim 1 wherein the second yoke portion includes a bias strip along a perimeter thereof.

5. The WLFF protection shirt of claim 4 wherein the bias strip is formed of the first material.

6. The WLFF protection shirt of claim 1 wherein the first yoke portion is quilted together with the second yoke portion.

7. The WLFF protection shirt of claim 1 wherein the first yoke portion has no shoulder seam.

8. The WLFF protection shirt of claim 1 wherein the first yoke portion has no armhole-sleeve cap seam.

9. The WLFF protection shirt of claim 1 wherein the first collar portion includes two layers of the first material and the second collar portion is positioned therebetween.

10. The WLFF protection shirt of claim 1 wherein at least one of the first right side cuff portion or the first left side cuff portion includes two layers of the first material and the second right side cuff portion is positioned therebetween. CA 3300834 Date reçue / Received date 2026-02-04 74 11. The WLFF protection shirt of claim 1 wherein the bodice portion includes a back bodice section, a left front bodice section attached to a left side of the back bodice section, and a right front bodice section attached to a right side of the back bodice section.

12. The WLFF protection shirt of claim 1 wherein the first yoke portion includes a right first yoke section and a left first yoke section that are attached together.

13. The WLFF protection shirt of claim 1 wherein the second yoke portion includes a right second yoke section and a left second yoke section.

14. The WLFF protection shirt of claim 1 wherein at least one of the right sleeve or the left sleeve includes an upper sleeve section, a front undersleeve section, and a back undersleeve section all attached together.

15. The WLFF protection shirt of claim 1 wherein the first yoke portion, the first collar portion, the first right side cuff portion, and the first left side cuff portion cover approximately 25% of the shirt area.

16. A method of protecting a firefighter comprising: placing a protection shirt having an outer portion and sleeves around a torso of the firefighter and with arms of the firefighter inserted through the sleeves thereof; and maintaining air gaps between at least one of neck, shoulders, upper torso or wrists of the firefighter and a proximal portion of the outer portion of the shirt. CA 3300834 Date reçue / Received date 2026-02-04 75 17. The method of claim 16 wherein the air gaps are maintained at all of the neck, the shoulders, the upper torso and the wrists of the firefighter.

18. The method of claim 16 wherein each air gap is independently between 0.05 and 8.0 millimetres. CA 3300834 Date reçue / Received date 2026-02-04