U.S. patent application number 11/069319 was filed with the patent office on 2005-09-08 for chemical and biological protective hood assembly.
Invention is credited to Courtney, Mark J., Pheris, Joanne G..
Application Number | 20050193472 11/069319 |
Document ID | / |
Family ID | 35539407 |
Filed Date | 2005-09-08 |
United States Patent
Application |
20050193472 |
Kind Code |
A1 |
Courtney, Mark J. ; et
al. |
September 8, 2005 |
Chemical and biological protective hood assembly
Abstract
Chemical and biological protective hood assembly. The hood
assembly comprises a head cover portion; a visor; a head
passthrough; and an air line passthrough.
Inventors: |
Courtney, Mark J.;
(Middletown, DE) ; Pheris, Joanne G.; (North East,
MD) |
Correspondence
Address: |
GORE ENTERPRISE HOLDINGS, INC.
551 PAPER MILL ROAD
P. O. BOX 9206
NEWARK
DE
19714-9206
US
|
Family ID: |
35539407 |
Appl. No.: |
11/069319 |
Filed: |
March 1, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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60549372 |
Mar 2, 2004 |
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Current U.S.
Class: |
2/202 |
Current CPC
Class: |
A62B 17/04 20130101 |
Class at
Publication: |
002/202 |
International
Class: |
A42B 001/04; A41D
013/00 |
Claims
What is claimed:
1. A hood assembly comprising: head cover comprising at least a
barrier film material; visor; head passthrough including neck
sealing means; and air line passthrough including air line sealing
means.
Description
RELATED APPLICATIONS
[0001] This application claims the benefit of Provisional U.S.
Patent Application 60/549,372, filed Mar. 2, 2004
FIELD OF THE INVENTION
[0002] This invention relates to chemical and biological protective
hoods, suits and systems.
BACKGROUND OF THE INVENTION
[0003] Current standard practice for responders to chemical or
biological releases is to wear a fully encapsulated suit when using
a self contained breathing apparatus ("SCBA") in a Hazardous
Materials ("HAZMAT") incident requiring vapor protection. In a
fully encapsulated suit the responder and the SCBA are completely
inside a chemical protective suit to prevent vapor ingress that
could contaminate the responder's skin, lungs, etc.
[0004] Non-encapsulating chemical and biological protective suits
have been under development for several decades, such as those
containing a chemical agent-adsorbing material, see for example, WO
83/02066. Many laminate and composite materials have been developed
to allow for the transport of water vapor while simultaneously
preventing the through-diffusion of liquids and chemical agents.
For example, adhesively bonded composites comprising a microporous
membrane and a nonwoven fabric, an activated carbon layer, and an
inner layer adapted to skin contact is described in WO 93/08024.
The technology for protection against chemical and biological
assaults while concurrently allowing passage of water vapor to pass
has resulted in many useful new composite constructions. For
example, U.S. Pat. No. 4,510,193, to Blucher, describes one such
sheet material comprised of activated carbon particles adhesively
bonded to an air permeable textile.
[0005] In HAZMAT incidents where liquid and vapor personal
protection are preferred or necessary, the wearer will normally use
a SCBA and dress in a fully encapsulated suit, commonly referred to
as a Level A ensemble design. The Level A suit will provide
complete contamination protection for the wearer, his clothing, and
his SCBA. However, the Level A designs tend to restrict user
movement and visibility and require the wearer to be completely
decontaminated in order to replace their SCBA air storage tank in
longer duration operations.
[0006] Non-encapsulating garment designs, in which the user wears
their respiratory protection outside the garment, provide the user
with greater mobility and visibility. However, non-encapsulating
designs offering complete skin protection, when worn in conjunction
with an SCBA, do not provide sufficient liquid and vapor
protection. In searching for designs to improve the liquid and
vapor protection when using an SCBA, doffing the garment without
compromising the respiratory protection becomes a problem. Many
schemes have been attempted, but not succeeded, to eliminate the
need of the wearer to disconnect his supplied airline in order to
doff a non-encapsulating suit offering vapor and liquid protection
for the user's entire body.
[0007] Thus, existing systems provide a number of user limitations
and force the wearer to choose between functionally limiting
designs and designs, which do not offer any substantial amount of
vapor and liquid protection. The present invention provides a vapor
and liquid protective, non-encapsulating design that insures the
chemical and biological protective suit is sealed from ingress of
chemical and biological assaults while also allowing for easy
donning and doffing and providing for the needs of a supplied air
respiratory air system.
SUMMARY OF THE INVENTION
[0008] The invention comprises a hood assembly for use in
protection against chemical and/or biological agents. The hood
assembly comprises: a head cover comprising at least a barrier film
material; a visor; a head passthrough including neck sealing means
at the neck region of a wearer, the neck sealing means being
capable of forming a relatively snug fit with a collar-region of
the wearer's garment or directly with the wearer's neck; and an air
line passthrough comprising air line sealing means, the air line
sealing means being capable of forming a relatively snug fit at the
surface of an air line which is passed through the air line
passthrough and connected to a breathing mask to be worn by the
wearer.
BRIEF DESCRIPTION OF THE FIGURES
[0009] FIG. 1 is a front view drawing of a protective hood assembly
containing a transparent visor according to the invention;
[0010] FIG. 2 is a side view drawing of a protective hood assembly
containing a transparent visor according to the invention;
[0011] FIG. 3 is a schematic drawing of an air line passthrough
according to the invention;
[0012] FIG. 4 is a drawing of a further hood assembly according to
the invention; and
[0013] FIG. 5 is a drawing of a protective coverall assembly
according to the inventor.
DETAILED DESCRIPTION OF THE INVENTION
[0014] A chemical and biological protective hood assembly for use
with supplied respiratory air systems is provided.
[0015] As shown in the Figures, hood assembly is comprised of a
head cover 1 comprising at least a barrier film material, such as a
fabric construction, that is chemically and biologically
protective, a visor 2, a head passthrough 3 including a neck
sealing means; and air line passthrough 4 including air line
sealing means, through which a supplied respiratory air hose or
similar device can be passed and yet sealed against hazardous
liquids and vapors.
[0016] Suitable barrier film materials include, for example,
synthetic film materials such as plastics, rubbers, elastomers,
etc. Moreover, preferred barrier film materials include fabric
constructions. The barrier film material should provide the
necessary level of protection as prescribed by the end application
and be sufficiently flexible so as to provide relative comfort and
ease of movement to the wearer. Suitable barrier film materials
(e.g., fabric constructions) should preferably pass the vapor
permeation and liquid penetration tests set forth herein. Although
any suitable barrier film material may be used, for simplicity the
remainder of the disclosure will refer to fabric constructions. It
should be understood that the above mentioned synthetic films are
also acceptable according to the invention.
[0017] The fabric construction may be comprised of at least one
woven or knit or nonwoven textile material and at least one barrier
material. The textile may be woven or non-woven, employing
synthetic fibers, natural fibers, or blends of synthetic and
natural fibers. The textile may also be knits, interlocks and
brushed knits. The barrier material may be laminated to the
textile, coated onto the textile, imbibed into the textile, or
otherwise affixed adjacent to the textile. In an aspect of the
invention, fabric construction comprises at least one layer of
fabric material and at least one layer of barrier material.
[0018] The textile and barrier material may be at least one
laminate of at least one fabric layer and at least one barrier film
material produced by any suitable method. Suitable methods are
known in the art and include those as described in, for example,
U.S. Pat. No. 5,289,644 to Driskill et al. For example, such
laminates can be produced by printing an adhesive onto one layer in
a discontinuous pattern, in an intersecting grid pattern, in the
form of continuous lines of adhesive, as a thin continuous layer,
etc., and then introducing the second layer in a way that the
adhesive effectively joins and adheres together the two adjacent
surfaces of an expanded polytetrafluoroethylene ("ePTFE") based
barrier film and the textile material. The first textile layer is
typically used to provide abrasion resistance that helps to protect
the barrier film material.
[0019] An optional second textile layer may be provided on the
inside of the fabric construction and is typically present to
provide both abrasion resistance to the side of the barrier
material opposite the first textile layer and to provide a more
comfortable surface to the wearer. The inclusion of a second
textile layer creates what is often referred to as a "3 layer"
laminate. A 3 layer laminate can be produced by printing adhesive
onto both sides of a barrier material and then introducing both a
first and second textile to opposing surface of the barrier
material onto which the adhesive has been printed. Alternately, a 2
layer laminate can be produced first and then an adhesive printed
or otherwise provided onto the barrier material side of the 2 layer
laminate prior to the introduction of a second textile layer onto
said second barrier material surface.
[0020] Alternatively, the textile and the barrier material can be
detached from each other except at isolated discrete connection
points such as around a perimeter of the article and/or at
irregular, sporadic intervals. A 3-layer construction can be
accomplished by optionally including a second textile layer on the
opposite side of a barrier film(s) from the first textile layer.
The second textile layer may comprise a woven, knit, nonwoven
textile, or any other flexible substrate comprising textile fibers
including, but not limited to, flocked fibers.
[0021] The barrier material should be resistant to chemical and
biological penetration and diffusion since it provides much of the
protective nature of the fabric construction.
[0022] A suitable barrier material useful for chemical and
biological protective fabric construction is a composite including
polytetrafluoroethylene film. Suitable polytetrafluoroethylene
containing protective fabric constructions are available from W.L.
Gore and Associates under part number ECAT 614001 B. Such
protective fabric constructions provide excellent chemical
penetration and permeation resistances in addition to high thermal
stability, both properties that are required for applications such
as fire fighting and hazardous material handling. In addition, the
impermeable nature of this type of protective fabric construction
provides excellent biological protection, making it ideal for many
types of emergency medical personnel. Alternatively, the barrier
material used in the chemical and biological protective fabric
construction can be any suitable, waterproof, breathable or
nonbreathable layer capable of providing the necessary level of
protection. For example, the fabric constructions known under the
tradename Tychem.RTM.fabric (from DuPont) are acceptable.
[0023] Turning back to the figures, FIG. 1 shows one aspect of the
invention wherein the protective hood assembly is shown to include
head cover 1 comprising fabric construction, visor 2, head
passthrough 3, and air line passthrough 4. As shown, the protective
hood assembly preferably should be of sufficient length so as to
extend down over the shoulders of the wearer, as shown by shoulder
cover section 11.
[0024] Head passthrough 3 includes neck sealing means. Suitable
neck sealing means include, for example, an elastic or elastomeric
material (e.g., a neck dam), or a stretchable fabric construction
such as a stretchable laminate, positioned such that the sealing
means will form a relatively snug fit around the wearer's neck or
the collar-region of the wearer's garment when worn, yet can be
stretched over the wearer's head for donning and doffing of the
hood assembly. Further neck sealing means can include, for example,
a cinching assembly, such as draw string, hook and loop fastener
straps, and elastic straps, for pulling the fabric construction
snug about the wearer's neck. Still further neck sealing means
includes an inflatable material, such as an inflatable collar that
can be inflated to form a seal against the wearer's neck or
collar-region. A partially inflatable material where the inflatable
material inflates to decrease the diameter of the neck region of
the hood such that a relatively snug fit around the wearer's neck
is formed can also function as suitable neck sealing means. An even
further neck sealing means includes a split-ring assembly that can
be closed about the wearer's neck to form a relatively snug fit.
The split-ring assembly preferably is a semi-rigid construction
comprising plastic, rubber, thin metal, etc., and includes a
closure means to enable the split-ring assembly to be donned and
doffed easily while also providing a relatively snug fit and a
secure seal between the ends of the split ring when closed.
[0025] In an aspect of the invention a garment for covering the
wearer's torso is provided (such as the coverall depicted in FIG.
5) with a collar 8 that is sufficiently high as to extend around
the wearer's neck and above the position of the neck sealing means
of the hood assembly. Likewise, the fabric construction of the hood
should be designed to extend down over the air line passthrough
4.
[0026] Neck sealing means can also be comprised of an elastomeric
material such as neoprene, butyl rubber, EPDM, nitrile,
chloroprene, fluoroelastomers, etc, that is formed into a suitable
circumferential geometry that will allow the wearer to easily slip
the hood assembly over his/her head, but still result in a
relatively snug fit around the wearer's neck. By "relatively snug"
it is meant that the fit around the wearer's neck (or in the case
of the air line passthrough, the outside surface of the air line)
is sufficiently tight as to provide the necessary protection
against the specific threat to which the wearer is to be exposed.
For example, if the hood assembly were to be used in an environment
that has been chemically contaminated, the "relatively snug" fit
would prevent the chemical agent from entering the hood assembly in
amounts considered dangerous to the wearer.
[0027] The visor 2 of the hood assembly can be any material that is
impermeable to the requisite challenges and provides sufficient
translucency or transparency and is of sufficient size to allow the
wearer to see. The visor can optionally be flexible. A composition
of polyvinyl chloride (PVC) and a fluoropolymer film is one such
flexible visor material that provides good transparency, excellent
chemical and biological penetration resistance, and high thermal
stability. In addition, other flexible, polymeric films can be used
including but not limited to composites of polycarbonate,
fluorocarbon-containing copolymer films, etc. Acrylic-based and
vinyl-based films may also be suitable as a visor material for some
applications.
[0028] Air line passthrough 4 can be a flexible port through which
a suitable air supply line can be passed and connected to an air
mask to be worn by the wearer. It should be understood that
additional passthroughs can be provided to the hood to accommodate
further passthrough items. The term "passthrough item" used herein
means any item that necessarily extends from the outside to the
inside of the hood, such as but not limited to further air supply
lines, respiratory air hose, tube, wire, cord, communication
equipment line, or other similarly long and flexible material. As
shown in FIG. 3, the air line passthrough can be comprised of a
flexible protective fabric construction which includes air line
sealing means. Air line sealing means can be any suitable means as
discussed above with regard to the neck sealing means. For example,
in an aspect of the invention, a compressible, elastomeric liner
section 9, and a means to secure 10 the elastomeric liner section 9
onto the outer surface of the air line can be used. Moreover,
suitable flexible protective fabric construction can be the
protective fabric construction described above for use as the hood
material. Other flexible protective constructions could also be
used as the passthrough. The elastomeric liner section 9 is
typically attached to or located on the inner surface of the air
line passthrough and should extend circumferentially around the
inner surface as to form a ring through which the air line would
extend. The securing means 10 can include any type of means capable
of forming a relatively snug fit with the air line, such as by
forcing the elastomeric liner 9 to be held firmly against the air
line. Some suitable securing means 10 include draw-cords (shown in
the Figure), clamps, Velcro.TM. fasteners, and elastic straps, or
any other material that can be used to pull the otherwise loose
flexible fabric layer/elastomeric liner firmly against the air
line. Alternatively, the air line passthrough could have an
elasticized end capable of sealing against the outer surface of the
air line.
[0029] In a further aspect of the invention a seal can be formed
across the garment zipper area. Most chemical and biological
protective suits require a zipper for donning and doffing. This
invention is particularly advantageous in that the neck sealing
means can be designed so as to form a relatively snug fit across
the zipper area of any garment to be used in combination with the
hood assembly. Thus, garments can be designed with zippers that
extend to the top of a high collar 8 and yet still form a
protective seal.
[0030] In practice, the steps for using the protective hood
assembly would comprise the following: a wearer would don a
suitable protective coverall or jumpsuit (such as coverall 7, shown
in FIG. 5); then mount a supplied respiratory air tank on his/her
back; next, the wearer should don the respiratory air mask; then
the air line from the tank is passed through the air line
passthrough and attached to a respiratory air mask, and then air
line sealing means are used to seal the air line passthrough
against the air line. followed by pulling the protective hood over
his/her head. Neck sealing means will provide the relatively snug
fit about the wearer's neck or collar of the wearer's coverall.
[0031] A second embodiment of this invention is suitable for wear
with a respiratory air mask that can accommodate an environmental
seal with a chemically and biologically protective hood as shown in
FIG. 4. This embodiment is similar to the first embodiment
described above except that respiratory mask sealing means 6 is
provided for sealing against an outer surface of the respiratory
air mask. Further passthroughs are optional. Respiratory air mask
sealing means provides sufficient compressive forces to provide a
relatively snug fit against the outer surface the supplied air
mask. Because the air line to the respiratory air mask does not
need to pass from the supplied air tank through the protective
barrier layer of the hood assembly, the air line passthrough is an
optional feature in this embodiment. Additional passthroughs,
however, may be advantageous in that it enables other hoses, lines,
wires, and similar things to be safely routed from outside to
inside the protective hood assembly. Head passthrough and neck
sealing means are also provided in this embodiment.
[0032] FIG. 5 shows a suitable garment construction that can be
used in combination with the hood assembly. Garment 7 and high neck
portion 8 provide a relatively snug fit between a protective hood
and high neck portion 8 such that any compressive forces of the
neck sealing means do not act to constrict the wearer's neck.
[0033] Other ways of ensuring a relatively snug fit between hood
and neck portion include a means to hold the neck portion 8 above
the neck sealing means of the hood. For example, providing a means
for pulling the neck portion 8 closer or even snugly against the
wearer's neck, such as providing a hook and loop fastening system
(e.g. VELCRO.TM. fastener) or a cinching means to the neck portion
8 can ensure that the neck portion 8 remains above the neck sealing
means of the hood.
[0034] In a further embodiment, the protective garment can comprise
a semi-rigid, split-ring assembly that encircles the wearer's neck.
The semi-rigid split-ring assembly can be either plastic, rubber,
or thin metal provided the modulus and design allow for ease of
bending while concurrently providing sufficient resistance against
any compressive forces of the neck sealing means. A typical
construction would have the protective garment 7 affixed to the
semi-rigid split-ring assembly and the neck sealing means affixed
to the protective hood assembly. The diameters of both the
semi-rigid ring assembly and the neck sealing means should be such
that the compressive forces between these abutting surfaces are
sufficient to provide a relatively snug fit between the neck
sealing means and high collar 8.
[0035] Closure means can be provided to enable the semi-rigid
split-ring assembly to be donned and doffed easily while also
providing a secure seal between the ends of this split ring when
closed. This closure means can be positioned in line with the
zipper area of garment 7 to provide even greater donning and
doffing ease while maintaining a satisfactory seal. This split-ring
design eliminates the need for a fixed ring assembly that is
sufficiently large to fit over the wearer's head, thereby
increasing wearer's mobility, comfort, and effectiveness. When used
to seal smaller appendages such as wrists and ankles, the
split-ring design may be optional. While the inventive elements of
this embodiment are as depicted as suitable for use with the
chemical/biological protective suits, it is equally applicable to
any other protective suit in which there exists a compressive seal
formed against the resistive forces of the wearer's body, including
but not limited to neck, wrists, and ankles.
[0036] In an aspect of the invention, the hood assembly is combined
with complimentary protective accessories (i.e. coveralls, gloves,
and boots) to form a protective ensemble. The protective ensemble
is preferably liquid proof and/or vapor proof. More preferably, the
protective ensemble meets the requirements for National Fire
Protection Association ("NFPA") 1994 Class 2 protection.
[0037] Further optional embodiments for the protective hood
assembly include arm straps 12 which can be provided to the hood to
allow for securing the hood to the wearer. For example, nylon
straps with locking/unlocking fasteners can be attached to the
lower edge of the hood, as shown in FIGS. 1 and 2. Use of such
straps (or similar means) will result in keeping the hood in better
position while the wearer moves about. Further embodiments can
include providing a device or means to relieve any pressure buildup
within the hood assembly, such as a check valve, etc.
[0038] It may be further desirable to include a moisture management
system located or locatable on the inner surface of the hood
assembly. During use, it is likely that moisture will be generated
in the hood due to, for example, operator perspiration and
respirator exhaust discharged into the hood. In order to reduce the
amount of moisture inside the hood, a device or multiple devices
can be installed on the interior of the hood to collect moisture
that is generated during hood use. Moisture can be collected in any
number of suitable methods, either by passive or active means. One
exemplary means includes a desiccant package in which a desiccant
is enclosed in a moisture vapor permeable fabric or other material
construction. The desiccant package can be attached to the inside
of the hood by several means such as hook and loop fastener,
magnetically, adhesively, etc. Favorable properties of the
desiccant package would be high moisture vapor permeation,
protection of the desiccant from contamination from body oils and
salts, containment of the desiccant to the confines of the package,
and non-melt characteristics when exposed to high temperatures.
Definitions
[0039] "Barrier material" refers to any material capable of
providing permeation resistance against the chemical and biological
challenges required for the specific end application.
[0040] "Breathable" refers to polymer film/textile laminates that
have a Moisture Vapor Transmission Rate (MVTR) of at least about
1,000 (grams/(m.sup.2)(24 hours)).
[0041] "Non-breathable" refers to polymer film/textile laminates
that have a Moisture Vapor Transmission Rate (MVTR) of less than
about 1,000 (grams/(m.sup.2)(24 hours)).
[0042] "Fabric construction" refers to a composite comprising at
least one textile material and at least one barrier material.
[0043] "Laminate" refers to any layered composite that comprises at
least one barrier material layer and at least one textile layer,
the layers of which are, typically, adhered together.
[0044] By "Adhered" or "Adhered together" it is meant that the
barrier material (e.g., ePTFE film) and textile material are joined
together by suitable bonding media.
Test Methods
[0045] A) Liquid proof shall mean that the hood when worn with
complimentary accessories (i.e. coveralls, gloves, and boots)
allows no liquid penetration when subjected to a shower spray test
such as ASTM F1359. A mannequin is outfitted with a
liquid-absorptive undergarment followed by a chemical/biological
protective ensemble. The mannequin is then subjected to liquid
spray from various angles at specified orientations for a fixed
time period. The chemical/biological protective ensemble is then
removed and the mannequin is examined. Any evidence of liquid on
the liquid-absorptive undergarment as determined by visual,
tactile, or absorbent toweling constitutes failure.
[0046] B) Vapor proof shall mean that the hood when worn with
complimentary accessories (i.e. coveralls, gloves, and boots)
allows less than 2% inward leakage when a wearer performs an
exercise protocol such as ASTM F1154 while operating in an
environment of 1000 ppm sulfur hexafluoride (by volume). NFPA 1994
2001 Edition describes an overall ensemble inward leakage test as a
method of quantifying ensemble design vapor protection.
[0047] In this test method, sampling ports are affixed at specified
positions on the wearer's body. The wearer dons the
chemical/biological protective ensemble and tubing connections are
then made to sampling pumps that are able to collect samples of air
inside the ensemble while being worn. The wearer enters a chamber
where a vapor simulant in a concentration of 1000 ppm sulfur
hexaflouride (by volume) is present. The user performs a specified
exercise protocol, such as described in ASTM F1154, and periodic
samples from inside the suit are taken. After multiple iterations
of the exercise protocol are performed and interior samples are
taken, the samples are then analyzed and the level of sulfur
hexafluoride that has entered the ensemble is examined. If the
interior ensemble concentration levels exceed 2% of the
concentration level present in the chamber, a failure is noted.
[0048] An alternative test method is the Man-In-Simulant Test
(MIST). The hood, when worn with complimentary accessories to
complete the protective ensemble provides a minimum system level
protection factor of 50 as tested by the MIST. The MIST procedure
may be based on Test Operations (TOP) 10-2-022, Chemical Vapor and
Aerosol System-Level Testing of Chemical/Biological Protective
Suits (January 2004). Thus, "vapor proof" shall also include hood
assembly when worn with complimentary accessories (i.e. coveralls,
gloves, and boots) that passes either test described in this
section B.
[0049] C) "Waterproof" is determined by conducting waterproof
testing as follows: Fabric constructions are tested for
waterproofness by using a modified Suter test apparatus, which is a
low water entry pressure challenge. Water is forced against a
sample area of about 41/4 inch diameter sealed by two rubber
gaskets in a clamped arrangement. The sample is open to atmospheric
conditions and is visible to the operator. The water pressure on
the sample is increased to about 1 psi by a pump connected to a
water reservoir, as indicated by an appropriate gauge and regulated
by an in-line valve. The test sample is at an angle and the water
is recirculated to assure water contact and not air against the
sample's lower surface. The upper surface of the sample is visually
observed for a period of 3 minutes for the appearance of any water
which would be forced through the sample. Liquid water seen on the
surface is interpreted as a leak. A passing (waterproof) grade is
given for no liquid water visible within 3 minutes. Passing this
test is the definition of "waterproof" as used herein.
[0050] D) Vapor permeation resistance of fabric constructions is
determined by ASTM F739, Standard Test Method for Resistance of
Protective Clothing Materials to Permeation of Liquids or Gases
Under Conditions of Continuous Contact. NFPA standard 1994,
Standard on Protective Ensemble for Chemical/Biological Terrorism
Incidents, requires ASTM F739 average breakthrough times shall not
be less than about one hour for fabrics to be considered permeation
resistant to specified chemical challenges.
[0051] E) Liquid penetration resistance of fabric constructions is
determined by ASTM F903, Standard Test Method for Resistance of
Protective Clothing Materials to Penetration by Liquids, for
measuring chemical penetration resistance to specified chemical
challenges. NFPA standard 1992, Standard on Liquid
Splash-Protective Ensembles and Clothing for Hazardous Materials
Emergencies, specifies that liquid penetration resistant fabrics
shall exhibit no penetration for at least one hour to a specified
group of chemicals in order to be classified as liquid penetration
protective fabrics.
[0052] The following non-limiting example is provided to further
exemplify aspects of the invention.
EXAMPLE
[0053] A hood was constructed of three-layer chemical/biological
protective fabrics, a chemical/biological protective seam tape, a
latex rubber was used as neck sealing means, an optically clear
polyvinyl chloride (PVC) film was used as the visor, a
0.045".times.1" open-cell foam rubber tape was used as the air line
sealing means, a nylon cording and strapping with locking fasteners
was used as the securing means for air line sealing means. The
three-layer chemical/biological protective fabrics consisted of a
fabric construction from W. L. Gore & Associates (part number
ECAT 614001B). Chemical/biological protective seam tape from W. L.
Gore & Associates (part number 6HSAJ025BLKBX) was used to seal
sewn-together seams. Latex rubber was affixed at the head
passthrough as the neck sealing means (part number
30003/1725AS102-4, Formco, Inc). The optically clear PVC visor had
a nominal thickness of 0.080 inches was supplied by McMaster Carr
(part number 87875K37).
[0054] Once the fabric, PVC film, and neck sealing means were
tailored to their desired shapes, the pieces were assembled in a
logical fashion with the use of a conventional sewing machine. All
sewn seams that would be exposed to the outside contaminated
environment were sealed with the chemical/biological protective
seam tape using a seam tape sealing machine. The end of the air
line passthrough was formed by inserting a nylon draw cord through
an inner sleeve formed in the fabric, attaching the open-cell foam
rubber tape to the inside diameter, and adding cord locking
fasteners. Nylon straps with locking fasteners were attached to the
outer edges of the hood flaps. Once the user dons the hood, the
nylon straps can be pulled under the user's arms and locked to keep
the hood in position.
* * * * *