Patent Publication Number: US-2007094763-A1

Title: Safety outerwear with fire resistant mesh

Description:
FIELD OF THE INVENTION  
      The present invention relates to the field of safety clothing, and more particularly, at least to the use of open-textured materials and fabrics in secondary flame resistant garments that satisfy the safety standards for workers exposed to risks of flash fires and/or electrical arc hazards.  
     BACKGROUND OF THE INVENTION  
      Each and every day, workers in the electrical maintenance, Utilities, oil, gas, petrochemical and steel industries work in environments that may expose them to hazards that could cause severe and/or fatal burn injuries. In the event of a momentary electric arc, flash fire, and/or molten metal splash exposure, standard work clothes that are not flame resistant may ignite and may continue to burn even after the source of ignition has been removed. Untreated natural fabrics may continue to burn until the fabric is totally consumed. Synthetic fabrics that are not flame resistant will also burn, with melting and dripping causing severe contact burns to the skin. In fact, various government reports may note that the vast majority of severe and/or fatal burn injuries may be due to the ignition and/or continued burning of an individual&#39;s clothing, and possibly not to exposure to the source of ignition itself.  
      Perhaps as a direct result, Occupational Safety and Health Administration (OSHA) regulations, American Society for Testing and Materials (ASTM) standards, National Fire Protection Association (NFPA) recommendations, and corporate safety guidelines may have encouraged, the adoption or flame resistant clothing for worker protection where a flash fire and/or electric arc hazard may be identified. In the prior art, chemical, petrochemical, and/or utility workers may have worn flame resistant clothing as a protective barrier against the intense neat from flash fires and electric arcs, and possibly to give such wearers a few extra seconds of escape time. Shirts, pants, coveralls, sweatshirts, rain wear, insulated all-season coveralls and coats may be commonly constructed using flame resistant materials. Other end users of flame resistant clothing in single and/or multi-layered configurations may include welders, firefighters, race car drivers and their crews, as well as the military, NASA astronauts, and rocket fuel handlers.  
      ASTM Standard F1.002, which is incorporated herein by reference, bears the title “Standard Performance Specification for Protective Clothing for Use by Workers Exposed to Specific Molten Substances and Related Thermal Hazards”, and its Abstract reads at least in part as follows: 
      “1.1 This performance specification covers textile materials to be used for protective clothing.     “1.2 Materials used for both primary protection and for secondary protection are covered.     “1.3 Protective properties relate to contact with molten substances and hot surfaces, and exposure to open flame and radiant heat.     “1.4 This performance specification covers clothing design characteristics that relate to the unique protective requirements of working with molten substances.     “1.5 This performance specification describes the properties of specific textile materials in their fabric or garment composite form as tested by laboratory methods and is not intended to be used to appraise the thermal hazard or fire risk under actual conditions. However, information on the thermal performance of clothing made from textile materials conforming to this specification may be used as an element in thermal risk assessment which takes into account all factors pertinent to the thermal hazard of a particular end use.”
 
 As may be generally and/or specifically defined in ASTM Standard F1002, flame resistant clothing may be generally divided into two or more distinct categories depending upon the application for which it is intended, namely, as follows: (i) primary protective clothing, and/or (ii) secondary protective clothing. 
   

      Primary protective clothing may be used when an employee may conduct tasks in a workplace where significant exposure to molten substance splash, radiant heat and/or flame may be likely to occur. Typically, these garments may have a heavier and/or multi-layer construction, and may be worn as a temporary outer layer of clothing (hereinafter, alternately referred to as “outerwear”) which may be put on over top of existing clothing before entering an environment that may have known hazardous conditions, and which may then be removed after completing a required task. Not unlike common safety eyeglasses, primary protective clothing may generally be considered standard occupational Personal Protective Equipment, or PPE, and may generally tend to be task specific. Firefighter turnout gear may comprise one such example.  
      Secondary protective clothing may be designed for continuous wear as outerwear that may or may not be put on over top of other clothing. For example, this category of protective clothing may include apparel such as shirts, pants, and/or coveralls for designated work areas where intermittent exposure to heat, flame and/or molten substance may be possible. The flame resistant secondary protective garments may generally have a single layer construction and/or may be intended to provide the wearer with immediate thermal protection from the flash fire, electrical arc flash, and/or molten metal splash at the exposure area. As well, secondary protective garments may be constructed using fabrics with acceptable char length, afterflame and afterglow values according to the Vertical Flame Test (Federal Standard 191A, Method 5903.1 which, after the source of ignition may be removed, may not continue to burn and/or which may help to limit the overall body burn percentage which may be suffered by the wearer.  
      From the perspective of an individual worker and/or a company&#39;s purchasing manager, the best flame resistant clothing purchase may ideally consist of garments that may be comfortable and/or offer the highest level of protection to numerous types of hazards. Also, most purchasing managers may generally agree that one of the most critical indicators of the success of a workplace protective apparel program may not necessarily reside in the protection offered by their flame resistant clothing. Rather, success may often be measured by the level of acceptance that the protective clothing may receive from the workers who may use the clothing on a daily basis, possibly without supervision and/or complaints about poor garment comfort, fit and/or style. Unfortunately, comfort and protection may long have been perceived to be mutually exclusive when it comes to flame resistant work clothing. Conventional thinking may have taught, perhaps more so than any other factor, that thermal protection may be largely a function of the thickness of an un-breached and/or non-permeable barrier between a wearer and a hazard. Also, the level of protection may generally have been thought to result from fabric composition, and/or the level of protection may have typically been thought to increase with higher fabric weights. Since higher fabric weights and/or thicknesses, combined with a general lack of breathability in a tightly woven fabric texture, may be commonly associated with poor comfort, it may not have been easy, in the prior art, to find protective clothing with both the highest level of protection and comfort, offered in the same garment, particularly as the issue of comfort may relate to worker heat prostration issues. As a result, managers and/or purchasers may long have struggled to find an acceptable balance between the two in the prior art, and manufacturers may even have taken tremendous steps to provide garment choices that are softer, lighter in weight, more breathable, and/or more comfortable.  
      Further, in hot environments, persons may often wish to wear shorts, also known as knee breeches, and/or other highly breathable and/or exposing articles of clothing, possibly for comfort as an outer layer of clothing. However, knee breeches and/or such other breathable and/or exposing articles of clothing may not constitute suitable apparel in circumstances wherein, inter alia, there is a risk of momentary electric arc, flash fire, and/or molten metal splash exposure, and/or where the knees of persons wearing such apparel may be apt to come into contact with rough surfaces. Indeed, and as aforesaid, in many such settings, applicable legislation may prohibit the use of knee breeches and/or other such potentially exposing articles clothing. Moreover, in some environments, temperatures may plummet significantly, possibly in a relatively short period, in which case, persons wearing shorts and/or other exposing articles of clothing as an outer layer of clothing may become uncomfortably cool.  
      The prior art may be replete with examples of jackets which may be removed and/or long pants which may be adapted to be worn as an outer layer of clothing and which include legs that may be removed from the knee down, thereby to possibly convert into an outer layer of knee breeches and/or other exposing clothing, and/or the reverse. U.S. Pat. No. 269,479 (Stretch et al.), issued Dec. 19, 1882, may be exemplary in this regard.  
      Such clothing articles may be beneficial in that, in hot environments, the clothing may normally be worn with the leg portions and/or other covering portions removed, and/or in circumstances when the wearer anticipates that his or her knees, lower legs, and/or other exposed body portions may come into contact with a momentary electric arc, flash fire, and/or molten metal splash exposure and/or rough surfaces, the leg portions and/or other covering portions may be reinstated, possibly for safety. However, in circumstances when the wearer may not be able to anticipate when his or her lower legs and/or other exposed body portions may be exposed to injury, convertible trousers and/or other convertible clothing represents no particular advantage, since, possibly for safety, the wearer may be mandated to wear the clothing with the leg portions and/or other covering portions in place at all times, possibly with consequent discomfort.  
      By way of providing a further background of the invention, impregnated flame resistant fibers in the prior art may have undergone a process whereby flame retardant chemicals became permanently infused within the cotton and/or other natural fibers themselves. Such treated natural fibers may have been previously used in combination with aramids and/or modacrylics as well. The INDURA® Ultrasoft fabric which is manufactured by Westex Inc., of Chicago, Ill., is a flame resistant cotton,/synthetic blend. The cotton in the INDURA® Ultrasoft fabric is impregnated to the core with a flame retardant chemical. It may be generally believed, though not essential to the present invention, that the INDURA® Ultrasoft fabric offers protection with the comfort and affordability of cotton. The INDURA® Ultrasoft fabric may have industrial applications and may provide effective protection against potential risks associated with welding and similar activities. The INDURA® Ultrasoft fabric may retain the beneficial properties of natural cotton for wearer comfort and absorbency. The LENZING FR® fiber is a natural fiber that is derived from wood and/or a natural raw material. LENZING FR® fiber is provided with a flame retardant substance incorporated throughout the cross-section of the fiber, which protective substance cannot be removed by washing and/or abrasion.  
      On the other hand, in the prior art, flame resistant “surface-treated” fabrics and/or fibers may be mainly distinguishable from other natural fabrics and/or fibers by virtue of fire retardant chemicals having been applied to the surface of the material or to the surface of the fibers themselves. The resulting flame resistance afforded to the fabric and/or fiber in this manner may generally not have been a permanent feature, and/or it may have washed out and/or have been worn off. An exemplary prior art fabric and/or fiber in this regard may be the PROBAN™ fabric and/or fiber manufactured and/or distributed by Rhodia.  
      In the prior art, aramids may generally have included, among other thins, NOMEX®, KEVLAR™ and TWARON™ fibers and/or fabrics—the last-mentioned one actually being a para-aramid nylon. NOMEX®, KEVLAR™ and TWARON™ are trademarks of DuPont. DuPont&#39;s NOMEX® IIIA aramid is a fabric that may have generally consisted of 93% NOMEX, 5% KEVLAR, and 2% carbon. Carbon may have been in NOMEX® IIIA fabric to reduce and/or dissipate static. Though not essential to the invention, it may be generally believed. A that DuPont&#39;s NOMEX® IIIA aramid possesses the following characteristics, among others: (i) it may be an inherently flame resistant anti-static fabric engineered to reduce “nuisance” static; and (ii) it may be self-extinguishing, and may not ignite melt, drip, and/or burn. Again, though it is not essential to the invention, these characteristics may be generally thought to make NOMEX® fabrics exceptional all-around fabrics for applications such as petroleum refining, petro-chemical, fire service, and/or gas and/or electric utilities. Though not essential to the invention, DuPont&#39;s prior art KEVLAR™ aramid fiber and/or fabric may be generally thought to be a strong ballistic flame-resistant material. In the prior art, KEVLAR™ fibers may have been used in chain saw protective pants and/or in other forestry applications, and/or in bullet proof vests, etc.  
      In the prior art, many textile manufacturers may generally have tended to use combinations or cottons, aramids and/or other synthetics. Over and above aromatic polyamides (or aramids), and though not essential to the invention, synthetic fibers and/or fabrics may have also included para-aramids, meta-aramids, polyamide-imides, polybenzimidazoles (PBI), celazoles, melamines, oxidized polyacrylonitriles and/or modacrylics. Synthetics may be petroleum-derived and/or man-made fibers. PBI is a heat and flame resistant fiber that may have a multitude of high temperature applications. Celazole is a family of high temperature PBI polymers that may be available in true polymer form. Basofil® fibers may be included in the general class of melamine fibers, which are heat and flame resistant fibers. Modacrylic fibers may have been the first flame resistant synthetic fibers, and it is generally believed, though not essential to the present invention, that they do not support combustion, are self-extinguishing, and do not drip.  
      By way of providing a still further background of the invention, ASTM document D3217-01a, which is incorporated herein by reference, is entitled “Standard Test Methods for Breaking Tenacity of Manufactured Textile Fibers in Loop or Knot Configurations”. This ASTM document may be considered relevant to assessing whether particular fibers may be considered to have a high elongation.  
      ASTM document D3822-01, which is also incorporated herein by reference, is entitled “Standard Test Method for Tensile Properties of Single Textile Fibers”. This ASTM document may be considered relevant to assessing the tensile properties of particular fibers. Its abstract reads, at least in part, as follows: 
          “1.1 This test method covers the measurement of tensile properties of natural and man-made single textile fibers of sufficient length to permit mounting test specimens in a tensile testing machine.”       

      ASTM document D1388-96(2002), which is still further incorporated herein by reference, is entitled “Standard Test Method for Stiffness of Fabrics”. This ASTM document may be considered relevant to assessing whether particular fabrics and/or clothing items may be considered to have a low stiffness. Its abstract reads, at least in part, as follows: 
          “1.1 This test method covers the measurement of stiffness properties of fabrics. Bending length is measured and flexural rigidity is calculated.”       

      Though American Association of Textile Chemists and Colorists (AATCC) Test Method 124-2005—which is similarly incorporated herein by reference and is entitled “Appearance of Fabrics after Repeated Home Laundering”—describes smoothness after repeated home launderings, this document may be helpful to define, with any such variations as may be necessary in the context, what may be meant by the phrase a “substantially smooth surface”. Its abstract reads, at least in part, as follows: 
          “1.1 This test method is designed to evaluate the smoothness appearance of flat fabric specimens after repeated home laundering.     1/2 Any washable fabric may be evaluated for smoothness appearance using this method.     “1.3 Fabrics of any construction, such as woven, knit and nonwoven, may be evaluated according to this method.”       

      ASTM document D3886-99(2006), which is also incorporated herein by reference, is entitled “Standard Test Method for Abrasion Resistance of Textile Fabrics (Inflated Diaphragm Method)”. This ASTM document may be considered relevant to assessing whether particular fabrics and/or clothing items may be considered to offer protection against abrasion. Its abstract reads, at least in part, as follows: 
          “1.1 This test method covers the determination of the resistance to abrasion of woven and knitted textile fabrics, both conditioned and wet, using the inflated diaphragm tester. This procedure is not applicable to floor coverings.”
 
 Of course, other procedures for measuring the abrasion resistance of textile fabrics are given in ASTM Test Methods D 3884, D 3885, D 1175, and in AATCC Test Method 93, each of which documents is also incorporated herein by reference. 
       

      ASTM document D737-04, which is additionally incorporated herein by reference, is entitled “Test Method for Air Permeability of Textile Fabrics”. This ASTM document may be considered relevant to assessing whether particular fabrics and/or clothing items may be considered highly breathable. Its abstract reads, at least in part, as follows: 
          “1.1 This test method covers the measurement of the air permeability of textile fabrics.     “1.2 This test method applies to most fabrics including woven fabrics, nonwoven fabrics, air bag fabrics, blankets, napped fabrics, knitted fabrics, layered fabrics, and pile fabrics. The fabrics may be untreated, heavily sized, coated, resin-treated, or otherwise treated.”       

      AATCC documents 132 and 158, which are likewise incorporated herein by reference, may be considered relevant to assessing whether particular fabrics and/or clothing items have good dimensional stability and/or low shrinkage and/or stretching, whether subjected to regular laundering or dry cleaning. ASTM document G 21-80, which is incorporated herein by reference and bears the title “Determining resistance to Synthetic Polymeric Materials to Fungi”, may be considered relevant in assessing the resistance of a particular fabric and/or clothing item to insects and/or fungi.  
      It may be an object of the present invention to obviate and/or mitigate one or more of the above-mentioned disadvantages of the prior art.  
      It may be an object according to one aspect of the present invention to provide cooler, more breathable flame resistant single-layer secondary protective clothing which may be constructed, in whole or in part, using substantially open-textured flame resistant materials, meshes and/or fabrics.  
      It may be an object according to another aspect of the present invention to provide open-textured materials and/or meshes and/or clothing made therefrom which may meet current recommended government and/or industry safety standards for flame resistant clothing.  
      It may be an object according to another aspect of the present invention to provide open-textured materials and/or meshes and/or clothing made therefrom which may outperform, under current recommended government and/or industry safety standards for flame resistant clothing, when compared to garments constructed from conventional, solids and/or closed-textured and/or tightly-woven flame resistant fabrics.  
      It may be an object according to another aspect of the present invention to provide convertible and/or double-layered flame resistant secondary protective clothing which may be constructed, in whole or in part, from substantially open-textured flame resistant materials, meshes and/or fabrics.  
      It may be an object according to another aspect of the present invention to provide open-textured flame resistant materials and/or meshes and/or convertible and/or double-layered flame resistant secondary protective clothing made therefrom which may meet current recommended government and/or industry safety standards for flame resistant clothing.  
      It may be an object according to another aspect of the present invention to provide open-textured flame resistant materials and/or meshes and/or convertible and/or double-layered flame resistant secondary protective clothing made therefrom which may excel, under current recommended government and/or industry safety standards for flame resistant clothing, when compared to garments constructed front a single-layer of conventional, solid, and/or closed-textured flame resistant fabrics.  
      It may be an object according to one aspect of the present invention to provide safety outerwear having a vent portion that possesses dimensional stability, low shrinkage and/or stretching, resistance to degradation by chemicals and/or industrial solvents, thermal stability, resistance to prolonged heat, a minimized embrittlement in extreme cold, ultra violet radiation resistance, and/or resistance to insects and/or fungi.  
      It may be an object according to another aspect of the present invention to provide an article of outer-layer safety clothing (herein, alternately referred to as “safety clothing” or “safety outerwear”—outerwear being defined herein to mean an article of clothing that is either adapted for exposure to outside environmental conditions and/or adapted and/or otherwise intended to be worn as an outer-layer of clothing—whether inside or out-of-doors) which may be relatively comfortable to wear in warm conditions, and/or which may, possibly at the same time, maintain protective qualities which may be comparable to those inherent in trousers and/or other coverings.  
     SUMMARY OF THE INVENTION  
      In accordance with the present invention, there is disclosed an article of safety, outerwear that includes a main body piece adapted to receive in encompassing relation at least a portion of the body of a wearer in use. The main body piece includes a garment wall that defines an inside wall portion and an outside wall portion. The inside wall portion is adapted to present a substantially smooth surface to the body of the wearer in use. The outside wall portion is adapted for substantially constant exposure to environmental conditions and to provide the wearer with protection against abrasion during normal activity selected from the group consisting of working activity and athletic activity. The garment wall is formed at least in part from a vent portion, such that at least a portion of each of the inside wall portion and the outside wall portion of the garment wall is defined by the vent portion. The vent portion is constructed solely from at least one layer of a mesh material. The vent portion is safety-rated with a flame resistant rating that qualifies the vent portion for flame resistant use in hazardous environments. The mesh material operatively has a substantially open texture for high breathability.  
      According to an aspect of one preferred embodiment of the invention, a substantial entirety of the garment wall may preferably, but need not necessarily, be formed from the vent portion.  
      According to an aspect of one preferred embodiment of the invention, the vent portion may preferably, but need not necessarily, be substantially co-extant with a substantial entirety of the main body piece.  
      According to an aspect of one alternate embodiment of the invention, the vent portion may preferably, but need not necessarily, be co-extant with only a portion of the main body piece.  
      According to an aspect of one preferred embodiment of the invention, the mesh material may preferably, but need not necessarily, be constructed at least in part from a synthetic flame resistant material.  
      According to a further aspect of a preferred embodiment of the invention, the synthetic flame resistant material may preferably, but need not necessarily, comprise a synthetic flame resistant fiber that may preferably, but need not necessarily, be characterized by low stiffness and high elongation, so as to preferably, but not necessarily, provide textile-like characteristics, and so as to preferably, but not necessarily, enable processing of the fiber on conventional textile equipment.  
      According to alternate further aspect of a preferred embodiment of the invention, the synthetic flame resistant material may preferably, but need not necessarily, comprise one or more fibers selected from the group consisting of aromatic polyamide fibers, para-aramid fibers, meta-aramid fibers, polyamide-imide fibers, polybenzimidazole fibers, celazole fibers, melamine fibers, oxidized polyacrylonitrile fibers, and modacrylic fibers.  
      According to an aspect of another preferred embodiment of the invention, the mesh material may preferably, but need not necessarily, be constructed at least in part from a natural material. The natural material may preferably, but need not necessarily, be selected from group consisting of plant-based fibers and silk-based fibers. Selected plant-based fibers may preferably, but need not necessarily be cellulose and/or cotton fibers.  
      According to a further aspect of a preferred embodiment of the invention, the natural material may preferably, but need not necessarily, comprise a material rendered flame resistant by surface treatment with a flame retardant chemical.  
      According to an alternate further aspect of a preferred embodiment of the invention, the natural material may preferably, but need not necessarily, comprise a natural fiber rendered flame resistant by impregnation of a flame retardant chemical into a substantial core thereof.  
      According to an aspect of another preferred embodiment of the invention, the mesh material may preferably, but need not necessarily, be selected from the group consisting of flame resistant perforated fabrics, flame resistant lattice-type fabrics, and flame resistant open-work fabrics. Selected perforated fabrics may preferably, but need not necessarily, be conventional mesh materials. Selected lattice-type fabrics may preferably, but need not necessarily, be materials having an open-weave structure. Selected open-work fabrics may preferably, but need not necessarily, be lace-type fabrics.  
      According to an aspect of one preferred embodiment of the invention, the flame resistant rating may preferably, but need not necessarily, comprise char length values, afterflame values, and afterglow values compliant with the vertical flame test under Method 5903.1 of United States Federal Standard 191A .  
      According to an aspect of one preferred embodiment of the invention, the flame resistant rating may preferably, but need not necessarily, comprise char, length values, afterflame values, and afterglow values compliant with the vertical flame test in accordance with the American Society for Testing and Materials D-6413 standard.  
      According to an aspect of one preferred embodiment of the invention, the flame resistant rating may preferably, but need not necessarily, comprise an arc thermal performance value rating substantially within the range of between about a 0.1 rating and about a 5.0 rating. The flame resistant rating may preferably, but need not necessarily, further comprise a hazard/risk category rating substantially within the range of between about a 0.1 rating and about a 1.0 rating.  
      According to an aspect of another preferred embodiment of the invention, the flame resistant rating may preferably, but need not necessarily, comprise an arc thermal performance value rating substantially greater than about a 5.0 rating. The flame resistant rating may preferably, but need not necessarily, further comprise a hazard/risk category rating of substantially greater than about a 1.0 rating.  
      According to an aspect of one preferred embodiment of the invention, the flame resistant rating may preferably, but need not necessarily, comprise a rating compliant with the National Fire Protection Association 2112 standard.  
      According to an aspect of one preferred embodiment of the invention, the mesh material may preferably, but need not necessarily, have an actual weight of substantially about 6.0 ounces per square yard. The flame resistant rating may preferably, but need not necessarily, comprise a thermal protective performance rating of substantially greater than about 6.0 calories per square centimeter. The thermal protective performance rating may preferably, but need not necessarily, be obtained in accordance with the American Society for Testing and Materials D-4108 standard.  
      According to an aspect of another preferred embodiment of the invention, the mesh material may preferably, but need not necessarily, retain a high visibility dye.  
      According to an aspect of one preferred embodiment of the invention, the main body piece may preferably, but need not necessarily, include a trunks outerwear part and a pair of tubular leg parts. The trunks outerwear part may preferably, but need not necessarily, be adapted to receive in encompassing relation the lower region of the torso of a wearer in use and may preferably, but need not necessarily, have apertures through which the legs of the wearer protrude in use. Each of the tubular leg parts may preferably, but need not necessarily, be adapted to receive therethrough a respective protruding leg of the wearer in use and each may preferably, but need not necessarily, extend between a respective upper end, connected to the trunks outerwear part, and a respective lower end, disposed adjacent to the ankle of the respective protruding leg. One vent portion may preferably, but need not necessarily, be provided in each leg part as a tubular vent portion that may preferably, but need not necessarily, extend, with respect to the respective protruding leg received in the each leg part in use, from about mid leg to about the ankle.  
      According to a further aspect of one preferred embodiment of the invention, the main body piece may preferably, but need not necessarily, be trouser outerwear.  
      According to an aspect of another preferred embodiment of the invention, the main body piece may preferably, but need not necessarily, include a trunks outerwear part, a pair of tubular leg parts, and a bib part. The trunks outerwear part may preferably, but need not necessarily, be adapted to receive in encompassing relation the lower region of the torso of a wearer in use and may preferably, but need not necessarily, have apertures through which the legs of the wearer protrude in use. Each of the tubular leg pars may preferably, but need not necessarily, be adapted to receive therethrough a respective protruding leg of the wearer in use and each may preferably, but need not necessarily, extend between a respective upper end, connected to the trunks outerwear part, and a respective lower end, disposed adjacent to the ankle of the respective protruding leg. The bib part may preferably, but need not necessarily, be securely attached to the trunks outerwear part. The bib part, the trunks outerwear part, and the leg parts together may preferably, but need not necessarily, form a bib overall. At least one vent portion may preferably, but need not necessarily, be provided in the bib overall.  
      According to an aspect of one preferred embodiment of the invention, the main body piece may preferably, but need not necessarily, include a trunks outerwear part, a pair of tubular leg parts, and a front-closure jacket part. The trunks outerwear part may preferably, but need not necessarily, be adapted to receive in encompassing relation the lower region of the torso of a wearer in use and may preferably, but need not necessarily, have apertures through which the legs of the wearer protrude in use. Each of the tubular leg parts may preferably, but need not necessarily, be adapted to receive therethrough a respective protruding leg of the wearer in use, and each may preferably, but need not necessarily, extend between a respective upper end, connected to the trunks outerwear part, and a respective lower end, disposed adjacent to the ankle of the respective protruding leg. The front-closure jacket part may preferably, but need not necessarily, be securely attached to the trunks outerwear part. The jacket part, the trunks outerwear part, and the leg parts may preferably, but need not necessarily, together form a coverall. At least one vent portion may preferably, but need not necessarily, be provided in the coverall.  
      According to an aspect of one preferred embodiment of the invention, the main body piece may preferably, but need not necessarily, include an upper torso outerwear part and a pair of tubular arm parts. The upper torso outerwear part may preferably, but need not necessarily, be adapted to receive in encompassing relation the upper region of the torso or a wearer in use, and it may preferably, but need not necessarily, have apertures through which the arms of the wearer protrude in use. Each of the tubular arm parts may preferably, but need not necessarily, be adapted to receive therethrough a respective protruding arm of said wearer in use, and each may preferably, but need not necessarily, extend between a respective upper end, connected to the upper torso outerwear part, and a respective lower end, disposed in a wristward direction from the respective upper end along the respective protruding arm. At least one vent portion may preferably, but need not necessarily, be provided in at least one of the upper torso outerwear part and the arm parts.  
      According to a further aspect of a preferred embodiment of the invention, the upper torso outerwear part may preferably, but need not necessarily, be shaped to define a front opening, and the upper torso outerwear part may preferably, but need not necessarily, include a front-closure means for securing the front opening of the upper torso outerwear part in a closed configuration.  
      According to a further aspect of a preferred embodiment of the invention, the long-sleeved pull-over shirt may preferably, but need not necessarily, be adapted to be worn as an outer layer of clothing.  
      According to an aspect of another preferred embodiment of the invention, the article may preferably, but need not necessarily, also include a covering shell that may preferably, but need not necessarily, be substantially secured to the main body piece for covering the vent portion. The covering shell may preferably, but need not necessarily, be adapted to be turned back from the vented portion into an opened configuration. The covering shell may preferably, but need not necessarily, be selectively securable in the opened configuration by securement means affixed to the main body piece.  
      According to an aspect of another preferred embodiment of the invention, the article may preferably, but need not necessarily, also include a covering shell that may preferably, but need not necessarily, be detachably secured by securement means affixed to the main body piece for covering the vent portion.  
      According to a further aspect of a preferred embodiment of the invention, the covering shell may preferably, but need not necessarily, be constructed of a fabric material of a substantially closed texture.  
      According to another aspect of a preferred embodiment of the invention, the fabric material may preferably, but need necessarily, be formed at least in part from a high temperature flame resistant petrochemically-based manufactured fiber. Alternately, the fabric material may preferably, but need not necessarily, be formed at least in part from a natural fiber that may preferably, but need not necessarily, be rendered flame resistant by a process selected from the group consisting of surface treatment with a flame retardant chemical, and impregnation of a flame retardant chemical into a substantial core thereof.  
      According to an aspect of another preferred embodiment of the invention, the main body piece may preferably, but need not necessarily, include a pocket means for temporarily storing items during a normal activity selected from the group consisting of workplace activities and athletic activities. The pocket means may preferably, but need not necessarily, comprise at least one pocket that may preferably, but need not necessarily, be sized to receive and store a covering shell which may preferably, but need not necessarily, be detachably securable to the main body piece for covering the vent portion.  
      According to an aspect of another preferred embodiment of the invention, the article may preferably, but need not necessarily, also include a pair of pads attached to the main body piece to preferably, but not necessarily, cover a first pair of body parts of the wearer in use that may preferably, but need not necessarily, be selected from a pair of knees and a pair of hips of the wearer.  
      According to a further aspect of a preferred embodiment of the invention, the pads may preferably, but need not necessarily, be removably attached to the main body piece.  
      Preferably, the mesh material may be adapted to provide the wearer with protection against burn and/or flame hazards, and/or electrical arc hazards.  
      In accordance with the present invention, there is disclosed safety clothing for use in environments requiring protective clothing, such as in industrial settings and in athletic pursuits, including rollerblading. According to this aspect of the invention, open-textured materials and open-textured fabrics may be utilized in secondary flame resistant garments that satisfy various recommended safety standards for workers exposed to risks of flash fires and/or electrical arc hazards.  
      It may thus be an object of this invention to obviate and/or mitigate one or more of the above-mentioned disadvantages of the prior art.  
      Other advantages, features and/or characteristics of the present invention, as well potentially as methods of operation and/or functions of the related elements of the structures and/or the combination of parts and/or economies of manufacture, may become more apparent upon consideration, of the following detailed description and/or the appended claims with reference to the accompanying drawings, the latter of which are be briefly described hereinafter. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The novel features which are believed to be characteristic of the safety outerwear with fire resistant mesh according to the present invention, as to its structure, organization, use, and/or method of operation, together possibly with further objectives and/or advantages thereof, will be better understood from the following drawings in which a presently preferred embodiment of the invention may now be illustrated by way of example. It is expressly understood, however, that drawings are for the purpose of illustration and/or description only, and are not intended as a definition of the limits of the invention. In the accompanying drawings:  
       FIG. 1  is a front elevational view of an article of safety clothing according to a preferred embodiment of the present invention;  
       FIG. 2  is a partially exploded view of the article of safety clothing shown in  FIG. 1 ;  
       FIG. 3  is a side elevational view or structure of  FIG. 2 ;  
       FIG. 4  is an exploded view of the unexploded portion of the article shown in  FIG. 2 ;  
       FIG. 5  is a front elevational view of an article of safety clothing according to a first alternate embodiment of the invention;  
       FIG. 6  is a view of the article of safety clothing shown in  FIG. 5 , shown in a first partially exploded configuration;  
       FIG. 7  is a view of the article of safety clothing shown in  FIG. 6 , shown in a second partially exploded configuration;  
       FIG. 8  is a view of the article of safety clothing shown in  FIG. 7 , shown in a fully exploded configuration;  
       FIG. 9  is a front elevational view of an article of safety clothing according to a second alternate embodiment of the invention;  
       FIG. 10  shows a recommended configuration for single-layer fabric TPP testing performed according to the ASTM D-4108/NPA 1971. standard;  
       FIG. 11  shows simulated flash-fire testing using a mannequin system at before, during, and after exposure to a simulated flash-fire;  
       FIG. 12  shows a tabulated summary of the hazard risk categories, and some sample common tasks, types of clothing, and typical ATPV values for single and multi-layer applications;  
       FIG. 13  shows a swatch card and close up of NOMEX® Type 462 test mesh;  
       FIG. 14  shows a graphic representation of the thickening of NOMEX III fabric when exposed to heat and flame, in accordance with ASTM-4108 TPP testing, with the shown thicknesses representing the nominal overall thickness of the fiber;  
       FIG. 15  is a photographic image depicting the carbonization and thickening of NOMEX® III fabric when exposed to heat and flame, in accordance with ASTM D-4108 TPP testing, with the shown thicknesses representing the nominal overall thickness of the fabric;  
       FIG. 16  shows a graphic representation of various sample garment testing results according to the NFPA 2112 standard with a three second exposure;  
       FIG. 17  shows various sensor locations on the front and rear sides of the DuPont THERMO-MAN® mannequin;  
       FIG. 18  shows a pair of convertible ventilated work pants according to the invention, with a right leg cover removed and with a left leg cover partially open;  
       FIG. 19  shows the images of the lower body burns sustained in tests  1  through  4 , wherein the color brown indicates second degree burns and the color red indicates third degree burns; and  
       FIG. 20  shows a tabulated summary of the mannequin test results in the four mannequin tests of  FIG. 19   
    
    
     DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT  
      Referring now to  FIG. 5  of the drawings there is shown an article of safety clothing according to a first alternate embodiment of the present invention and designated with general reference numeral  20 .  
      As best indicated in  FIG. 7 , the article  20  comprises a main body piece  22 . In the preferred embodiment illustrated, the main body piece  22  takes the form of a pair of trousers adapted to be worn as an outer layer of clothing. The trousers or main body piece  22  include a trunks part  24  which is also adapted to be worn as an outer layer of clothing, and a pair of tubular leg parts  28  (hereinafter, alternately referred to as pant leg parts). The trunks part  24  is adapted to receive in encompassing relation the lower region of the torso of a wearer in use and has apertures, defined in dotted outline in  FIG. 7  and designated with general reference numerals  26 , trough which the legs of said wearer protrude in use. The tubular pant leg parts  28  are each adapted to receive therethrough a respective protruding leg of said wearer in use and extend between a respective upper end  30 , connected to said trunks part  24 , and a respective lower end  32 , disposed adjacent the ankle of said respective protruding leg in use.  
      In the preferred embodiment illustrated, the trunks part  24  is substantially opaque, so as to conceal the pelvic region of the wearer in use, and is constructed of relatively sturdy and washable material of substantially closed texture.  
      Each pant leg part  28  of the preferred embodiment includes a tubular vent portion  34  extending, with respect to the respective leg disposed within said each leg part  28  in use, from about mid-leg to about the ankle.  
      The vent portion  34  is constructed substantially from mesh. The mesh preferably has a substantially open texture for high breathability, and presents a substantially smooth surface to the legs of the wearer in use. The mesh is adapted to provide the wearer with protection against abrasion in a normal activity selected from the group consisting of working and athletic activities. In the preferred embodiment illustrated, the mesh is a mesh material that is adapted for high visibility, for safety.  
      In the first alternate embodiment illustrated, a reinforced cuff  36  is sewn onto the mesh at the lower end  32  of the leg part  28 . The provision of such reinforced cuff  36  avoids undue wear, which might otherwise occur if the mesh extended fully through to the lower end  32 .  
      As best seen in  FIG. 6 , other features of the first alternate embodiment include a pair of first pads  38  which are removably attached to the main body piece  22  to cover respective knees of the wearer in use, as well as a pair of second pads  40  which are removably attached to the main body piece  22  to cover the respective hips of the wearer in use. As best indicated in  FIG. 7 , such removable attachment is effected, in the preferred embodiment, by hook  42  and loop  44  fasteners, of the type sold by Velcro Inc. under the trade-mark VELCRO, secured to the pads  38 ,  40  and the main body piece  22 , respectively. The first pads  38  and the second pads  40  are shown attached to the main body piece  22  in  FIG. 6 , and detached therefrom in  FIG. 7 .  
      As a further feature illustrated in  FIG. 5 , a pair of tubular leg shells  46  are preferably provided, and detachably secured to the main body piece  22  for covering the pant leg parts  28  and, when attached, the first pads  38 . Shells  46  are constructed of relatively durable, weatherproof, washable and fire-resistant material of substantially closed texture, so as to maximize protection from, inter alia, the elements and workplace hazards, when attached.  
      Such detachable securement of the shells  46  is effected, in the preferred embodiment illustrated, by a plurality of conventional snaps. Each snap comprises a male snap  50  and a female snap  52 . The female snaps  52 , as illustrated in  FIG. 7 , are fixedly secured to band portions  35  which extend about the pant leg parts  28  and about the reinforced cuffs  36 . The male snaps  50 , as indicated in  FIG. 6 , are fixedly secured about the inner periphery of tubular fillet portions  37  which are disposed at opposite ends  54  of the shells  46 .  
      In use, the article of safety clothing  20  can be worn in the manner of conventional trousers. In, for example, cold weather, the shells  46  may be slipped over the leg parts  28 , and secured to the trunks part  24  by snaps  50 ,  52 . In hot weather, on the other hand, the process may be reversed, and the shells  46  may be rolled up and conveniently stored in, for example, a lunch box, thereby to expose the mesh and provide comfort to the wearer, while at the same time providing protection against abrasion and burn injuries. Depending upon the type of activity in which the wearer is to be engaged, the first pads  38  and the second pads  40  may be secured to the main body piece  22 , or removed from the main body piece  22  and stored.  
      In the first alternate embodiment illustrated, the reinforced cuffs  36 , fillet portions  37  and band portions  35  are constructed of a reflective fabric, so as to render the wearer more visible to, inter alia, motorized vehicles.  
      A preferred embodiment of the invention is illustrated in  FIGS. 1 through 4 . The article of safety clothing of this embodiment, designated with general reference numeral  20 ′, differs from the first alternate embodiment in that a zippered-front jacket part  70  is provided and securely attached to the trunks part  24 , with the jacket part  70  and the main body piece  22  together forming a coverall  72 .  
      As well, in contrast to the situation of the preferred embodiment wherein the pant leg parts  28  were tailored in the manner of a conventional pair of trousers, the tubular vent portion  34  of each pant leg part  28  in the first alternative embodiment tapers towards the lower end  32 , and the leg shells  46  are similarly tapered. Among other things this feature permits the leg shells  46  to be interchangeable, for use on other leg. In most other material respects, the structure of the preferred embodiment is identical to that of the first alternate embodiment.  
      A second alternate embodiment of the invention is illustrated in  FIG. 9  and designated with general reference numeral  20 ″. In contrast to the first alternative embodiment wherein a jacket part  70  was provided, a bib part  74  is provided in the second alternative embodiment. The bib part  74  is securely attached to the trunks part  24 , with the bib part  74  and the main body piece  22  together forming a bib overall  76 . In all other material respects, the structure of the second alternate embodiment is substantially identical to that of the preferred embodiment, and accordingly, is not described. In substantially greater detail herein.  
      Various other modifications may be used in the design and manufacture of the article of safety clothing according to the present invention without departing from the spirit and scope of the invention.  
      For example, whereas the vent portions of the preferred embodiment extend from about the knee to about the ankle, such that the non-mesh portions of the pant leg parts and the trunks part form knee breeches, it will be evident that the vent portions could be smaller or larger, to suit the style of the wearer.  
      Further, whereas the first pads and the second pads of the preferred embodiment are removably attached by hook and loop fasteners, it will be evident that other means for such removable attachment, such as, for example, zippers, could be utilized.  
      Moreover, the first pads and the second pads could be rigidly affixed, by stitching, or omitted altogether.  
      Yet further, whereas the shells of the preferred embodiment are secured by snaps, it will be evident that securement could be effected through other conventional means, such as zippers, buttons or hook and loop fasteners.  
      As well, whereas in the preferred embodiment illustrated, the reinforced cuffs, fillet portions and band portions are constructed of a reflective fabric, it should be understood that alternatively, reflective material could be secured to the main body piece, for example, in a vertical line along each outer seam.  
      Moreover, while reinforced cuffs are provided in the preferred embodiment, it should be understood that cuffs are not essential. For example, the ends of the pant leg parts could be provided with drawstring closures, elastic banding or a flap-type closure, with hook and loop fasteners, in circumstances wherein it was desired to ensure a snug fit around, for example, the safety boots of a wearer. Stirrups could also be provided, so as to ensure that the pant leg parts did not inadvertently ride up on the legs of the wearer, and expose same to possible injury.  
      It is additionally noted, with regard to each of the embodiments and garments described herein, that the vented mesh portion may extend substantially over the entire garment so as to be substantially co-extensive therewith, or preferably it may only extend over a portion thereof. The garment preferably includes covering shells that are adapted to be removably fastened over the vented mesh portions, or alternately, it may not be provided with any covering shells whatsoever. Any such covering shells might include zippered fasteners and might also, or instead, open and roll, turn, and/or fold back from the vented mesh portions to be subsequently snapped in place in the opened configuration.  
      Further still, it should be appreciated that while pants, coveralls, overalls, long sleeved shirts and jackets are described herein, the invention may comprise any form, shape or configuration of garment provided with a flame resistant vented portion that is constructed of a breathable and substantially open-textured flame resistant material, whether the material is inherently flame resistant at the fiber level, or whether it is treated so as to render it flame resistant.  
      Accordingly, it should be understood that the present invention is limited only by the accompanying claims and the claims of any regular patent application claiming priority therefrom, as purposely construed.  
      Provided hereinbelow is an additional detailed description of the preferred embodiment of the invention, together with tables which are provided for the purpose of illustration and description only, and are not intended as a definition of the limits of the invention, but rather of some of its flame resistant advantages in relation to, among other things, momentary electric arcs, flash fires, and/or molten metal splash exposure.  
      In the prior art, flame-resistant primary and secondary garments may have been constructed using fabrics that were woven either from man-made fibers, from natural fibers, and/or from a combination of the two.  
      The predominant man-made flame resistant (hereinafter FR) material that has been in use in the prior art may have been a product called NOMEX® material NOMEX® is an E. I. DuPont registered trademark for its family of aromatic polyamide (aramid) fibers. Aramid fibers are inherently flame-resistant, i.e., the flame resistance is an inherent property of the polymer chemistry, meaning that the fibers themselves may not be subject to burning in air. NOMEX® material may not melt and/or drip, and/or it may merely char when exposed to high temperatures for prolonged periods. It may also provide a high degree of heat resistance and/or it may be extremely resistant to chemical attack. These properties may not diminish during the life of the fiber, and the fiber&#39;s low stiffness and high elongation may give textile-like characteristics which allow for it to be processed on conventional textile equipment. DuPont&#39;s KEVLAR® material may be a much stronger fiber from the same aramid family, and though it may be best known for its use in bulletproof vests it is also commonly used in flame resistant garments.  
      In the prior art, traditional natural fibers such as cotton may also have be rendered flame resistant after being surface-treated with a flame retardant chemical, and/or by infusing such chemicals into the very core of the fibers. Industry leaders in this flame retardant treated (hereinafter, FRT) area of technology may include Chicago, Ill. based Westex, and their line of INDURA® and INDURA® Ultra Soft® chemically treated fabrics. In INDURA® engineered fabrics, the flame retardant chemical which may have been impregnated into the core of a cotton fiber may act as a catalyst that may promote the charring of the fabric when exposed to flames. Though not essential to the working of the present invention, this accelerated charring may be generally believed to prohibit the support of continued combustion by starving the flame of its fuel source. Contrary to popular belief, however, the flame retardant chemical may act in its solid form by creating an exothermic reaction to produce this char, and the mechanism of action may not be based on a gaseous process of extinguishing or “snuffing out” the flame.  
      In the prior art, fabrics for thermal protective apparel may be evaluated for various properties using a broad range of test methods based on industry standards. In particular, there may be four laboratory test procedures which may be commonly used to demonstrate the unique flame resistant characteristics of any particular fabric. These may include the Vertical Flame Test, the Thermal Protective Performance Test or (TPP) Test, the Instrumented Mannequin Tests for Flash Fires, and the Instrumented Mannequin and Panel Tests for electric arc exposure. These tests may be used as benchmarks to achieve NFPA 2112 and NFPA 70E certification for potential new FR or FRT fabrics. Industry certification aids in the commercialization of any new FR or FRT fabrics because most of the potential end users require garments that are made using certified or “rated” (herein, alternately also referred to as “safety-rated”) fabrics. To achieve certification, independent testing as per these four tests may be required. Once a fabric has been “rated”, or in other words, satisfies the minimum requirements as per these tests, it may be used in any configuration in garment construction as the fabric may have been labeled with a protective “rating” specific to its construction, fiber content, and/or weight. Armed with this knowledge, purchasers may then make informed clothing-buying decisions, possibly by simply selecting from garments constructed from safety-rated fabrics that may satisfy the level of protection that their employees may require in their particular workplace. This fabric rating system may also eliminate the need for garment manufacturers to test every individual existing an/or new garment design, as the continuing costs of the independent testing might otherwise quickly become prohibitive.  
      The Vertical Flame Test (Federal Standard 191A, Method 5903.1 and/or ASTM D-6413 standard) may measure the relative flammability of a fabric specimen suspended vertically in a three sided frame. A methane burner may provide a small igniting flame which may then be allowed to burn on the bottom edge of the fabric for 12 seconds. The char length, afterflame (the amount of time flames may continue to be observed on the fabric surface after the burner is turned off or removed), afterglow (the amount of time the fabric may continues to glow after any afterflame stops) and/or other relevant observations may be recorded. This test may typically be a qualitative pass/fail indicator of fabric flammability and may be importance for protective apparel, because a fabric that may ignite and/or burn may contribute to burn injury rather than reducing it. However, the vertical flame test may not measure thermal protective performance and, consequently, it alone may not be an effective discriminator among flame resistant materials. Table 1 may show typical results of vertical flammability tests which may have been performed on solid fabrics of NOMEX® IIIA, 65%/35% polyester/cotton and 100% cotton.  
                           TABLE 1                           Weight   Char length   Afterflame       Fabric   (oz/yd2)   (in)   (sec)                                                NOMEX ® IIIA   14.5   3.3   0       NOMEX ® IIIA   6.1   3.1   0       65%/35% Polyester/Cotton   8.6   12.0   48.5       100% Cotton   9.0   12.0   36.0                  
 
      The thermal protective properties of fabrics and/or fabric systems may be demonstrated through the use of the Thermal Protective Performance (TPP) Test, as may be described in National Fire Protection Association Standard NFPA 1971 and American Society for Testing and Materials (ASTM) D-4018. This test may also be used to assess the integrity of fabrics under thermal load—a potentially important consideration in protective apparel. The TPP test may not be applicable to non-FR fabrics.  
      The equipment which may be required to perform the TPP test may be seen in  FIG. 10 . As normally practiced, a combined convective/radiant heat source with a heat flux of 2 calories per square centimeter per second may be impinged upon the outer surface of a 4-inch by 4-inch square area of the fabric system, and the time required to reach the equivalent of a second-degree burn at the calorimeter on the other side of the fabric system may be recorded. This time (in seconds), multiplied by the heat flux of the exposure, may give the TPP rating of the system. The higher the TPP value, the more protection a fabric or system may provide to the wearer.  
      As mentioned above, a recommended configuration for single-layer fabric TPP testing performed according to the ASTM D-4108/NFPA 1971 standard may be seen in  FIG. 10 . Such testing may typically includes a calorimeter, at least one ¼ inch spacer, the test fabric, a movable shutter, a gas burner, and/or radiant tubes. ASTM D-4108 may specify two methods for TPP testing. When testing single-layer fabrics, a ¼-inch spacer may be placed between the fabric sample and the heat sensor, possibly to simulate the normal fit of protective clothing and/or to allow the fabric to reach as high a temperature as may occur in an actual flame exposure. TPP results for single-layer standard woven fabrics of NOMEX® IIIA are listed in Table 2, where it may be seen that, for a specific material type, the TPP value may increase with increasing fabric weight. When testing multilayer fabrics and/or systems, such as firefighters&#39; turnout coats, the ASTM standard may specify that the sample and/or heat sensor be in contact with the innermost fabric layer of the system and/or that no spacer is to be used for multilayer fabric samples. It may be important to note at this time that, when multiple layers of FR fabrics are evaluated using these test methods, the test results may be higher than the additive TPP rating for each layer. This result may be explained by enhanced insulation resulting from a combination of heat transfer through the different layers and/or by entrapped air between the layers.  
               TABLE 2                          Sample TPP Ratings of Single Layer Fabrics per ASTM D-4108 with       Combined Convective and Radiant Heat Source       (recommended Configuration for Single-Layer Fabrics) *                                 Actual Weight   TPP               Fabric   (oz/yd 2 )   (cal/cm 3 )                       NOMEX ® IIIA   4.5   11.8           NOMEX ® IIIA   6.0   13.3           NOMEX ® IIIA   7.5   15.3           65% Polyester/35% Cotton       N/A - Ignites           100% Cotton       N/A - Ignites                         2.0 cal/cm 3 -sec heat flux. Fabrics were home laundered one time prior to testing.                N/A Not Applicable.             
 
      Along with the Vertical Flame Test and the TPP Test, actual garments constructed from FR and FRT materials may be burn tested on instrumented mannequins in accordance with ASTM F1930, the “Flash Fire Mannequin Test for Predicted Body Burn Injury”. DuPont&#39;s mannequin system, the THERMO-MAN® system, is an instrumented laboratory mannequin that may utilize skin model software to determine the predicted burn injury in a carefully controlled, reproducible laboratory flash fire. It may be generally believed, though not essential to workings of the present invention, that the idea is to simulate actual conditions that workers may be exposed to in, for example, a petrochemical refinery flash-fire. A simulated flash-fire testing using the THERMO-MAN® system may be seen in  FIG. 11  at three different stages, namely, before, during, and after exposure. Data obtained from one hundred and twenty-four (124) heat sensors distributed over the mannequin body may be used to measure the heat transmitted from the fire through the test garment to the surface of the mannequin. A sophisticated computer program may then calculate the predicted percentage of second and/or third-degree burns and/or may indicate the burn injury locations for the selected simulated flash fire exposure conditions. Under guidelines from NFPA 2112 and ASTM 1930, the THERMO-MAN® mannequin may be dressed in a T-shirt and briefs of 100% cotton as well as the garment to be tested, and may then be subjected to a propane gas flash fire of a minimum of 3 seconds in duration, with a heat flux of 2.0 cal/cm 2 /sec.  
      Under these conditions, garments made form standard 6.1 oz/yd 2  solid woven/closed textured fabrics of inherently flame-resistant NOMEX® IIIA material may generally limit the predicted second-degree and/or third-degree body burns to substantially less than or equal to about 35%. In a similar test, garments made from untreated 100% cotton (6.5 oz/yd 2  shirt+8.5 oz/yd 2  pants) and/or from untreated 65%/35% polyester/cotton (7.5 oz/yd 2  coverall) may exhibit predicted second and/or third-degree burns in the substantial range of from about 75% to about 90% of the body. Data compiled by the American Burn Association may indicate that a body burn level in the substantial order of about 90% of the body may translate into substantially less than or equal to about 30% chance of survival for the persons in the 20s and 30s age groups, and/or substantially less than or equal to about 15% chance of survival for persons in the 40s and 50s age groups. In contrast, the chance of survival corresponding to a burn injury level in the substantial order of about 40% of the body may be greater than or equal to about 80% for all age groups. It may be important to note here that, in order to achieve ratings for fabrics to be used for FR garments as per this test, NFPA 2112 may set the test failure at above about 50% Total Body Burn.  
      When compared to a flash fire as described earlier, the intense energy and/or very short duration of an electric arc flash may represent a very unique exposure. While it may be generally well-recognized that exposure to electric arcs can cause electric shock injury as the arc current passes through and/or along the surface of the human body, it may not be as well-recognized that the intense radiant and/or convective energy from an electric arc and/or the subsequent ignition of work clothing may cause serious burn injury, possibly even if there may be no contact with the arc. When an electric current passes through air between ungrounded conductors and grounded conductors, the temperatures may, even if only substantially briefly, reach substantially in the order of about 35,000° F. In fact, non-contact burn injuries may make up the majority of the injuries resulting from electric arc accidents.  
      Untreated cotton clothing may sometimes have been worn by electric utility workers in the prior art who may not be exposed to electric arc hazards, and/or where their potential arc exposure may be so minimal that there may be insufficient incident energy available to ignite untreated cotton clothing. However, everyday work clothes made from regular cotton and/or poly/cotton fabrics, regardless of weight, may be readily ignited at some exposure level and/or may continue to burn, which may add to the extend of injury which might be sustained from the arc alone. It was perhaps for these reasons that ASTM F1506 (“Standard Performance Specification for Textile Materials or Wearing Apparel for Use by Electrical Workers Exposed to Momentary Arc and Related Thermal Hazards”) may have been developed to give minimum performance specifications for protective clothing. The major requirement of this specification may be that the fabric is flame resistant, as may be determined in accordance with a standard vertical flame test.  
      The potentially heightened awareness in recent years of arc flash hazards may have prompted changes to the National Fire Protection Association (NFPA) 70E standard. The latest edition of the NFPA 70E standard (“Standard for Electrical Safety in the Workplace”) was published in 2004. The standard may states as follows: “employees shall wear FR clothing wherever there is a possible exposure to an electrical arc flash.” It may include a chart which, although it may not be reproduced herein, lists common tasks an electrical and/or maintenance worker may perform and it may assign a respective hazard/risk category (HRC) that is to be associated with each task.  
      ASTM may have developed a test method to assist in determining and/or comparing the protective capacity of various flame resistant fabrics against electric arc flashes, namely, ASTM F1959 being a “Standard Test Method for determining the Arc Thermal Performance Value (ATPV) of Materials for Clothing”. Using this test, the protective performance of various work wear fabrics and/or systems in an electric arc exposure may be determined using instrumented panels and/or mannequins. The mannequins and/or panels may be equipped with copper calorimeters to measure temperature rise, in a manner that may be generally similar to the TPP test method described earlier. When this test method is run, the arc discharge may cause a dramatic temperature rise in the receiving sensors over a short period of time (typically less than 1 second). The temperature rise at each calorimeter may be compared with available second-degree burn criteria to determine whether a burn may be predicted under the test conditions. In addition, observations may be made regarding fabric ignition, melting, dripping, shrinkage, brittleness, and/or weakness, possibly in addition to observations as to whether the fabric “breaks open” and may consequently be thought, according to the prior art, to no longer provide a barrier against heat and/or flame. Using this method, the data for ATPV for fabrics may be obtained, the fabrics may be assigned an ATPV value and/or rating, and the resulting clothing which is made therefrom may then be associated with the proper HRC guidelines, as described earlier. At this time, it may again be relevant to note that, as was the case with the TPP ratings of fabrics, FR and/or FRT fabrics may also show a higher combined ATPV rating when used in layered applications than the sum of their individual ratings alone. Again, this result may be explained by enhanced insulation resulting from a combination of heat transfer through the different layers and/or entrapped air between the layers.  
      A tabulated summary of the hazard risk categories, and some sample common tasks, types of clothing, and typical ATPV values for single and/or multilayer applications may be seen in  FIG. 12 .  
      It is extremely important to stress that, while regular, closed-textured, and/or solid-woven FR and/or FRT fabrics meeting minimum recommended NFPA 2112 and/or NFPA 70E standards for flame-resistant secondary garment construction may have been readily available in the prior art, the prior art does not disclose the use of a single-layer of open-textured FR and/or FRT materials and/or fabrics that satisfy these same guidelines, nor is there any prior art which teaches the added protective benefits associated with the use of open-textured materials in flame resistant clothing. Though not essential to the working and/or utility of the present invention, it may be generally believed, perhaps because one of the main end-user complaints regarding flame resistant work wear may pertain to heat prostration issues arising from a lack of breathability of closed-textured fabrics, that the use of FR and/or FRT open-textured meshes, perforated fabrics, lattice-type fabrics, and/or open-work fabrics may provide extremely breathable FR and/or FRT garments which may help to alleviate one or more of the aforementioned problems.  
      Recently, various testing of the article of safety outerwear  20  according to the present invention was carried out using a vent portion formed from an open-textured mesh. The test open-textured mesh was constructed from a NOMEX® Type 462 athletic type mesh, in an attempt to determine its suitability for use in single layer flame-resistant secondary garments. In particular, the tests were conducted to confirm that open-textured fabrics might be rated according to the aforementioned standards, and so as to prove their appropriate use in any configuration, whether provided in single and/or multiple layers, and whether provided with or without other tightly-woven flame resistant fabrics, in the construction of flame-resistant clothing according to the present invention. It may be worthwhile to note that, in the prior art, NOMEX® meshes may have been generally used in high temperature filtration, airline interior and/or military materials applications, but there is no prior art to suggest their use in externally exposed, and/or in safety-rated single-layer, clothing applications.  
      The mesh that was tested according to the invention was a 6.0 oz. NOMEX® Type 462 material that was obtained from Tek-Knit Industries of Montreal Quebec, in Canada. As discussed more generally hereinabove, Type 462 staple NOMEX® fibers may be a blend of NOMEX® and/or KEVLAR® brand fibers and/or P-140—a static dissipative carbon fiber. In the prior art, when the staple fibers may have been converted to closed-textured woven fabrics for use in thermal protective apparel, it may have been widely known commercially as NOMEX® IIIA material. Each such closed-textured woven fabric may have been rated according to fabric weight with its corresponding TPP and/or ATPV vales. A sales swatch card (from the Montreal mill), and a close up of a representative sample of the NOMEX® Type 462 mesh used in the tests performed according to the invention may be seen in  FIG. 3 . The close up which may be seen in  FIG. 13  may also demonstrate the open-texture of the mesh. Although clearly marked according to fabric weight and fiber type, the swatch card attached to the mesh label makes no mention of NOMEX® IIIA materials, nor does it provide TPP and/or ATPV values for the mesh—all of which are common practice when marking fabrics thought to be suitable for FR clothing. The similarly complete lack of both a TPP rating and/or an ATPV rating on the tested FR mesh may have been, in part, a factor motivating the recent tests performed on the mesh according to the invention  
      When looking at the texture of the flame-resistance mesh in  FIG. 13 , the ratio of air holes and/or “open-textured” areas compared to fiber and/or “closed-textured” area may be substantially in the approximate order of about 40% of the total surface area. It may be important to note, at this time, that a person having ordinary skill in the art would, in view of the positive test results obtained thus far, have a reasonable expectation that the test results that were obtained using this mesh (which are discussed elsewhere herein) would be substantially equivalent to those test results which might reasonably be predicted and may yet be obtained using other types of similarly weighted open-textured FR and/or FRT fabrics and/or materials (e.g., lace-work, latticed, and/or perforated materials, among others), provided that the aforementioned ratio of air holes to fiber (holes:fiber) remains substantially the same.  
      Preliminary Vertical Flame and TPP tests carried out on swatches of mesh material, corresponding in all substantial respects to that which is represented in  FIG. 13 , have indicated that such mesh material, contrary to what a person having ordinary skill in the art may ha a priori expected on the basis of the prior art, satisfies current fabric guidelines according to NFPA and ASTM standards for use in single-layer flame resistant secondary garments. Vertical Flame test have shown the mesh to have acceptable ratings for char length, afterflame and afterglow. TPP tests have demonstrated that, even with its substantially open texture, the tested mesh on its own passes minimum guidelines for thermal protective performance when used as a single layer. Though not essential to the working and/or utility of the present invention, it is anticipated that awaited results from ATPV testing which may have been recently performed on the mesh may yield comparable results.  
      Though not essential to the working and/or utility of the present invention, in hindsight, the satisfactory TPP results achieved by this particular mesh texture may also be partly explained by some of the built-in properties of the NOMEX® fibers themselves. Though not essential to the working and/or utility of the present invention, when exposed to intense heat, the NOMEX® fibers may be generally thought to carbonize and become thicker, forming a protective barrier between the heat source and the sensors. Thus, in hindsight, the NOMEX® fiber itself may help to increase the overall TPP rating in three ways: 
          i. The fiber itself may absorb heat energy during the carbonization process.     ii. The fiber may swell and/or help to seal openings in the mesh, possibly decreasing air movement and/or the associated convective heat transfer. A graphic representation of the thickening of NOMEX.® III closed-textured fabrics, when exposed to heat and flame, may be seen in  FIG. 14 . Though not essential to the working and/or utility of the present invention,  FIG. 14  may accurately depict, in accordance with ASTM-4108 TPP testing, shown thicknesses representing the nominal overall thickness of the fiber.     iii. One or both of the fiber and/or the fabric may thicken, possibly increasing the insulative barrier and/or reducing conductive heat transfer. The carbonization and/or thickening of NOMEX® III closed-textured fabric, when exposed to heat and flame, may be seen in  FIG. 15 . Though not essential to the working and/or utility of the present invention,  FIG. 15  may accurately depict in accordance with ASTM D-4108 TPP testing, shown thicknesses representing the nominal overall thickness of the fabric.        

      While no other FR and/or FRT meshes may have been existence in the prior art, a person having ordinary skill in the art would, in view of the positive test results obtained thus far, have a reasonable expectation that other fabrics, fibers, and/or materials that may undergo a thickening and/or a carbonization process, when exposed to intense heat and/or flame (such as, for example, Westex&#39;s INDURA® and INDURA® Ultra Soft® chemically treated cotton fabrics), would produce comparable results under similar conditions. As well, by increasing and/or decreasing the aforementioned holes:fiber ratio (i.e., aperture size) in the mesh and/or in other perforated, lacework, and/or latticed materials, a person having ordinary skill in the art would, in view of the positive test results obtained thus far, have a reasonable expectation that various acceptable TPP and/or ATPV test results are yet to be documented according to the NFPA 2112 and/or NFPA 70E standards. Moreover, a person having ordinary skill in the art would, in view of the positive test results obtained thus far, have a reasonable expectation that, according to the invention, such alternate textures and/or aperture sizes may be adjusted to suit the minimum thermal protective needs of many different end-users, while still affording the maximum ventilation characteristics.  
      While, as aforesaid, the Vertical Flame and/or TPP and/or ATPV results on the aforementioned mesh may have been very positive, the thermal protective properties that the mesh exhibited when burn tested using the instrumented Mannequin Test for Flash Fires proved to be even more dramatic.  
      NFPA 2113 and Canadian General Standards Board (GCSB) 155.20 define a flash fire as follows: “A rapidly moving flame front which can be combustion explosion. Flash fire may occur in an environment where fuel and air become mixed in adequate concentrations to combust. Flash fire has a heat flux of approximately 84 kW/m 2  for relatively short periods of time, typically less than 3 seconds.” 
      As a result, 3 seconds of flash fire exposure may have been established as the NFPA 2112 timeframe for analysis of the performance of secondary protective clothing and/or fabrics during the mannequin test. Often, exposure times above three seconds may be used to more completely profile fabric protective performance for use in secondary garments. That said, when the risk of exposure is greater than 3 seconds, layered secondary and/or primary garments may be highly recommended. As well, although three seconds may be used, possibly in conjunction with the 50% Total Body Burn pass/fail threshold, to determine a fabric&#39;s potential suitability for use in protective clothing, it may be widely accepted that the latent heat retained in the fabric of the garments and/or in the air trapped inside continues to contribute to additional 2 nd  and/or 3 rd  degree body burns, possibly long after the 3 second exposure has ended. For this reason, the mannequin may usually be monitored for a full 60 seconds, possibly to better measure actual final total body burns.  FIG. 16  may illustrate the effects of the latent heat and/or its contribution to additional burns after the three seconds of flame exposure may have ended. That is, a graphic representation of various sample garment testing results according to the NFPA 2112 standard with a three second exposure may be seen in  FIG. 16 . As is evidenced in the  FIG. 16  graph by the continued upward trend in the percentage of total body burns which may be sustained after three seconds, both the NOMEX® and the INDURA® closed-texture garments showed the effects of this residual heat in the fabrics and/or in the air trapped underneath of them.  
      As previously mentioned, DuPont&#39;s THERMO-MAN® mannequin may be equipped with one hundred and twenty-four (124) heat sensors which may be distributed over the mannequin body. These heat sensors may be used to measure the heat which may have been transmitted from the fire, through the test garments to the surface of the mannequin. A map of the individual sensor locations may be seen in  FIG. 17 . That is, various sensor locations on front and rear sides of the DuPont THERMO-MAN® mannequin may be seen  FIG. 17 . With this map, it may be possible to analyze the 2 nd  and/or 3 rd  degree burns that may be expected to occur at any location on the body. Using it, a person of ordinary skill in the art would be able to narrow her focus and/or analyze the data returned from the lower body exclusively, possibly thereby allowing, in hindsight, such a person to better scrutinize the protective performance of an open-textured mesh material.  
      For the mannequin tests performed according to the invention, DuPont&#39;s THERMO-MAN® mannequin was dressed in ventilated work pants as per a preferred embodiment of the invention that is fully described in detail elsewhere herein. In brief, the ventilated work pants according to the invention may be best described as having a solid, closed-fabric upper portion (from about the knee to the waist) that is securely attached to lower leg portions (from about the knee to the ankle). The lower leg portions are predominantly constructed from a substantially open-textured fabric, such as, for example, an athletic mesh. Solid fabric bottom cuffs and/or lower side seam reinforcement strips may be exceptions to the otherwise open-textured construction of the lower leg portions. Optionally, ventilated work pants may be convertible, and such convertible ventilated work pants may be worn (i) with a set of lower leg covers on, or (ii) with them off. Convertible ventilated work pants may preferably include separate, detachable solid-woven lower leg covers that can be attached to the uppers at about the knee, in order to substantially cover the mesh portions when desired. An image of a pair of convertible ventilated work pants according to the invention is shown in  FIG. 18 . More particularly,  FIG. 18  shows a pair of convertible ventilated work pants, as viewed with a right leg cover thereof removed and with a left cover thereof partially open.  
      For the tests that were performed according to the present invention, the closed-textured or woven upper portion (from about the knee up, of the pants was constructed using a standard 6.0 oz. NOMEX® IIIA fabric. The lower cuffs, lower side seam reinforcement straps, and detachable leg covers were also constructed from this material. The front and back of the lower legs (from about the knee down) were constructed entirely from the Tek-Knit 6.0 NOMEX Type 462 mesh, with the exception of the cuffs and side strips as previously noted. The upper body was dressed for the tests in a standard plain weave 6.0-7.5 oz, flame-resistant long-sleeved shirt and, in compliance with ASTM F1930 and NFPA 2112 guidelines, the mannequin was pre-dressed in a T-shirt and briefs of 100% cotton.  
      According to the invention, no fewer than four separate tests, in total, were run using three different configurations of the convertible ventilated work pants, All pants tested were of the same listed size, and were made using the same patterns and methods of construction. All pants tested were subjected to a more rigorous 4 second exposure. Tests #1 and #2 were conducted with the pants in the “open mesh leg” configuration; that is, with the open-textured mesh lower legs exposed to the full force of the simulated flash fire. Test #3 had the pants in the “full leg covers on” configuration, meaning that the covers were re-attached over top of the mesh legs, thereby creating a double fabric layer comprised of the covers and the underlying mesh legs. Finally, for Test #4, the lower leg mesh portions were cut off before the solid leg covers were re-attached, leaving a single layer of solid woven material (the covers) covering the lower legs. The rationale for the removal of the underlying mesh portions for Test #4 was perhaps to simulate a regular pair of single layer secondary NOMEX® IIIA work pants.  
       FIG. 19  provides a visual representation of the test data, depicting the lower body burns sustained in test Nos. 1 through 4, wherein the color brown indicates second degree burns and the color red indicates third degree burns.  
      When analyzing the data from the lower body sensors, and through not essential to the working and/or utility of the invention, some conclusions may be immediately drawn. Test #3, with the double fabric layer comprised of the covers and the underlying mesh legs, was the best performing tested configuration from a percentage of body burn perspective. This result may perhaps have been expected because of the previously mentioned increased TPP values that may generally be associated with layered flame-resistant fabrics. The results for Test #3 may be perceived as vastly superior to the other test results and may generally indicate that, when the convertible pants according to the invention are used with their covers on, such as, for example, in cool weather applications an/or when the need for additional protection is anticipated, the underlying mesh legs and the layer of insulating air between the two fabrics may be generally believed to provide for a much improved level of protection from immediate burn injury over a single solid-fabric layer (as was tested in Test #4). It is additionally generally believe, though not essential to the working and/or utility of the present invention, that residual heat retained in the fabric of the outer solid lower leg covers may have played a substantially diminished role in contributing to additional burning on the lower legs, as these covers were held away from the skin by the underlying layer of mesh. This conclusion may draw support in part and/or be evidenced by the fact that the majority of the burn injuries recorded during Test #3 may be generally seen to have occurred on the upper legs, where only a single layer of the solid tightly woven fabric was present.  
      While the additional protection that resulted from the layering effect in Test #3 may, in hindsight, have been predicted to certain degree, the protective properties demonstrated by the single-layer of open-textured material in Tests #1 and #2 was both dramatic and unexpected.  FIG. 20  shows a tabulated summary of the data that was collected from the sensors on the lower mannequin for Test Nos. 1 through 4.  
      Although all three configurations may be generally observed to have passed NFPA 2112 percentage of body burn minimum standards, especially when one considers that the exposure time was a more rigorous 4 seconds, both Test #1 and Test #2 outperformed Test #4 with respect to the total percentage of body burn experienced from the waist down. More significantly, while the percentage of sensors that recorded body burns from the knee up remained relatively consistent for all four tests (substantially in the range of about 20% to about 30%, Test #1 and Test #2 may both be seen to have outperformed Test #4 with respect to the percentage of burns from the knee down. The data may generally indicate that improved performance resulted from a greatly decreased percentage of 2 nd  degree body burns experienced in areas covered only by the open-textured material. Such a conclusion may lead to a corollary conclusion being made, namely, that the open-textured lower legs according to the present invention allowed for a venting effect that may have enabled quick cooling of the garment according to the invention. This cooling may, in turn, have reduced any additional burns that might otherwise have resulted, in normal circumstances, from the residual heat retained in the fabric itself and/or from the heat trapped next to the skin beneath the closed textured material. In essence, while the lower TPP rating of the open-textured mesh material may have allowed for higher initial 3 rd  degree burns, the overall effect may have been to reduce the total combined second and/or third degree body burn percentages in the areas of the mesh and as a result, possibly to provide an improved total body burn percentage. It should perhaps be once again specifically noted that the aforementioned conclusions and beliefs concerning mechanisms underlying the working of the present invention are not essential to working and/or utility of same.  
      Nonetheless, the potential significance of this aforementioned venting effect should not be underestimated when it comes to potential improvements in the protective properties of flame-resistance clothing. The documentation to date that might support the existence of this venting effect suggests that single layer flame-resistant secondary garments, such as, for example, shirts, pants, and/or coveralls, may be safety-rated and constructed entirely from open-textured fabrics and/or materials. Moreover, persons having ordinary skill in the art should appreciate that the data also suggests that open-textured garments may, in fact, provide equivalent and even increased protection against body burns when compared to conventional closed-textured and/or tightly-woven fabrics. Perhaps more importantly, the evidence may suggest that these same open-textured materials and/or fabrics may satisfy the NFPA and ASTM requirements necessary to be safety-rated as certified fabrics. Such certification would facilitate the use and/or adoption of open-textured materials an/or fabrics, either on their own in combination with any other FR and/or FRT rated fabrics, in single or multiple layers, in any configuration, on a wide variety of garments in a wide variety of contexts.  
      Of course, combination of closed and open-textured fabrics could also be used to create either standard or convertible type garments to suit the specific protective needs of a variety of different end-users. For example, refinery workers in the southern U.S., who may be more concerned with flash fires, might opt for long-sleeved shirt and/or pants and/or coveralls constructed entirely from mesh. Electric utility workers, on the other hand, may have an intermittent but frequent need for garments with increased TPP and/or ATPV ratings, depending on the Hazard Risk Category of the particular job. In this regard, such utility workers may prefer to use layered convertible-type garments that may provide additional protection, when required. As well, convertible-type garments may provide for superior all-season applications in certain contexts.  
      In will, in any case, be appreciated by persons having ordinary skill in the art that, according to the invention, manufacturers may be able to provide end-users with cooler, more comfortable, and/or lighter weight flame-resistance garments to satisfy their specific needs.  
      In closing, it may be worthwhile to once again note that various other modifications may be used in the design and/or manufacture of the article of safety clothing according to the present invention without departing from the spirit and scope of the invention, which is, of course, limited only by the accompanying claims.