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Clothing for Work and ProtectionR. Jeffries, British Textile
Technology Group, Manchester (UK)
The purpose of this Paper is to discuss var ious are as of
workwear (inparticular, protective apparel) in relation to the
nature and propertlesof the man-made fibres and polymers from which
these types ofclothing are made. For some kinds of workwear (e.g.
certain types ofcareer apparel and corporate clothing), the
functional requirements aremodest. little more in fact than those
requir ed for everyday clothing,although the stylisti c demands of
this kind of workwear tan be highso as to ensure that the soclal,
psychologi cal, and cultural needs ofthe wearer are satisfied (i.e.
to secure user acceptance). But in otherareas of workwear the
personal protection of the wearer is the pnmefunction, and here the
technical requirements of the apparel tan beat a demandingly high
level (although even with this severely functionalclothing the
wearers social, psychological , and cultural needs mustbe born i n
mind dunng the deslgn of the clothlng to ensure that thewearer of
the clothing is in all senses ,,comfortable).The main pari of the
Paper concentrates on considerations of thefunctional requirements
of clothing for protection of the body against(a) heat and fire,
(b) weather, (c) dirt, contaminants, and chemicals ,(d) statlc
electrical hazards, and (e) ballistic impacts; but the protectionof
the environment against cont amination by the person (,,clean
roomapparel) is also condidered. The Paper deals only with the
protectionof the torso Parts of the body; the protection of the
head, eyes, hearing,respiratory System, hands, and feet in working
environments, althoughobiously of major importante, are not
considered.In practicall y al l aspects of protective clothing, the
protective functionIS of itself usually not too difficult to
achieve to a reasonable level. Thesevere technical Proble ms that
may arise do so mainly because of theneed to combine the protection
with (a) wearability (the clothing mustbe comfortable to wear in
three ways: thermally, in relation to personalmobility and
dexterity, and in relation to social and psychological needs)and
(b) reasonable tost and economics. In many cases the fabrics
andgarments may need to meet conflicting technical requirements
andtherefore compromis es are needed to achieve a finally
acceptable itemof protective workwear.The Paper examines the
man-made fibres at present avail able that aredesigned to have the
types of high Performance properties needed invarious forms of
protective clothing: heat resistance. and flameretardancy, hi gh
strength and modulus, low electrical resistance,Chemical
resistance. Although the emphasis WIII be on the presentp&tion
in relation to the fibres themselves, some attention will also
bepaid to the role of finishing agents in optlmising the protective
and otherfunctions of apparel assembli es made from these fibres.
The major roleof polymeric coatings in apparel designed to have
high Performancebarner properties allied to acceptable comfort
propert ies is considered.Verschledene Aspekte der Arbeitskleidun g
(vor alle m Schutzkleidung)werden i n bezuq auf den Charakter und
die Eigenschaften von Chemie-fasern und Polymeren diskutiert, die
zur Herstellung dieser Kleidungs-arten verwendet werden. Bel
einigen Arbeitskleidungstypen (z.B. ge-wisse Arten von Berufs- und
Firmenkleidung) sind die Funktionsan-forderungen gering, und zwar
kaum mehr als die Anforderungen anAlltagskleidung. Was aber die
Stilistik dieser Art von Arbeitsbekleidungbetnfft, knnen die
Anforderungen hoch sein, um sicherzustellen, dadie sozialen,
psychologischen und kulturellen Bedrf nisse des Trgersbefriedigt
sind (d.h., da die Kleidung eine gute Aufnahme beim An-wender
findet). Bei anderer Arbeit skleidung aber ist die
Hauptfunktion,den Trger selbst zu schtzen, und hier knnen die
technischen Anfor-derungen an die Kleidung auerst hoch sein (aber
auch bei dieserhochfunktionellen Kleidung mssen die sozialen,
psychologischen undkulturellen Bedrfnisse des Trgers schon bei der
Gestaltung der Klei-dung bercksichti gt werden, u m sicherzustell
en, da der Trger sichin jeder Hinsicht ,, komfortabel fhlt).Der
Vortrag befat sich im wesentlichen mit den Funktionsanforderun-gen
an Kleidung, die vor (a) Hitze und Brand, (b) Witterung,(c)
Schmutz, Kontaminationen und Chemikalien, (d) den Gefahren
derstatischen Aufladuna und Ce) ballistischen Aufschlaen schtzen
sol l;der Schutz der Umwelt geben menschlich bedingte
Kontamination(..Reinraumbeklei dunol wird auch berleot. Der Vortraq
umfat nurden Schutz des Ober%rpers; der Schutz des Kopfes, der
Augen, derOhren, des Atmungsystems, der Hnde und der Fe am
Arbeitsplatz,der zwar auch von groer Bedeutung ist, wird nicht
diskutiert.Bei fast allen Aspekten der Schutzbekleidung, was die
Schutzaufgabebetrifft, ist es normalerwei se nicht schwierig, einen
annehmbarenSchutzwlrkungsgr ad zu erreichen. Die schweren
technischen Pro-
pleme, die sich ergeben knnten, sind hauptschlich darauf
zurckzu-fhren, da die Schutzwirkung mit (a) Tragekomfort (der
Tragekomfortder Kleidung mu drei Erfordernissen entsprechen:
bezglich t hermi-scher Eligenschaften, Beweglichkeit und sozialer
sowie psychologi-scher Bedrfnisse), mit (b) zumutbaren Kosten und
Wirschaftli chkeitkombiniert werden mu. In vielen Fllen mssen die
Kleidungsstckevielleictit widersprchl iche technische Anforderungen
erfllen, die zuKompromissen fhren, um ein geeignetes
Arbeitsschutzkleidungs-stck eqdgltig zu erreichen.Untersucht werden
die zur Zeit am Markt verfgbaren Chemiefasern,die die fr jegllchen
Schutzbeklei dungstyp erforderlichen Hochlei-stungseigenschaften
aufweisen: Hitzebestndigkeit und Schwerent-flammbarkeit,
Hochfestigkeit und Hochmodul, niedrige elektrische Be-stndigkeit,
chemische Bestndigkeit. Obwohl der Schwerpunkt desVortrags auf dem
heutigen Stand der Chemiefasern selbst liegt, wirdauch die Rolle
der Chemikali en und Veredlungsmitt el bei der Optimie-rung der
Schutzwirku ng und anderer Funktionen von Bekleidung ausdiesen
Chemiefasern kurz in Betracht gezogen. Die Hauptrolle der
Po-lymerbeschich tungen auf Bekleidungsartikeln, die
hervorragendeSperreigenschaften, verbunden mit annehmbaren
Komforteigenschaf-ten, aufweisen sol len, wird ausfhrlich
diskutiert.
A. IntroductionThe purpose of this Paper is to review the
present Position inrelation to clothing for work and protection,
and howdevelopments in man-made fibres have made possible
majoradvances in the functional properties of these types of
apparel.All types of clothing need to have a balance of
properties:aesthetic, cultural, and protective, allied to good
economics. Inrelation to work and protection, it is clear that many
forms ofeveryday clothing have a ,,werk function (e.g. Office wear)
andthat nearly all forms of clothing have a ,,protective function;
infew real life situations could the human being functi on
withoutsome iorm of protection, however small.In this Paper, the
Position and present Status is reviewed for abroad spectrum of work
and protective clothing, ranging fromclothing where the protective
function is no more than that ofordinary clothing at the one
extreme to apparel with a highlyprotective and specialised function
(e.g. fire-fighters apparel) atthe other extreme. The emphasis will
be very much on the,,highly protect ive end of the range.In a
general sense, any article that covers any part of the bodymay be
designated as ,,clothing: gloves, shoes, headwear, justas much as
the main items of apparel covering the main torsoand limb areas of
the body, and the need for the protection ofeach of these Parts of
the body varies widely in the technicalnature of the protection
required and the ways in which thisprotection is able to be
achieved. However, protection of thehead, the hands, and the feet
quite clearly involves factors andProblems that are over and above
the protective requirementsof the main torso and li mb Parts. These
factors include protectionof the eyes and hearing, the fact that
the hands tend to be inparticularly close contact with potential
hazards (e.g. chemicals),and that the wearing of gloves in some
circumstances involvesProblems of tactility and manual dexterity,
and the sweatdesposal Problems often encountered in the wearing of
shoesand boots. These ,,extra functional requirements in
the.protection of the head, hands, and feet are not dealt with in
thisPaper
B. WorkwearIn defining workwear it is possible to divide such
apparel intothree broad categories, although there is clear overlap
betweenthem. First, the so-called ,,corporate or ,,Company
clothing: themain pur pose of this clothing is to identify a person
with aparticular Company, or a role within that Company, and to
projectto the world a pleasing, aesthetically attractive, image for
theCompany. The protecti ve function of this apparel is often
littlemore than that required of ordinary, everyday, clothing i.e.
aminimal protection against normal life Situation!;.
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The second category of work clothing combines elements ofthe
requir ements of Company clothing (identification with aCompany and
of Status within the Company, Promotion of goodCompany image) with
elements of a low level of protection i.e.protection against
mechanical wear and darnage to, orcontamination of, the persons
personal clothing during, say, thehandling of machinery, or in
situations where the occasionalsplash of some innocuous powder or
liquid might occur duringlow risk manufacturing processes (e.g. in
the food industry).Clothing in this second category needs to be
aestheticallyattractive and .fashionable, durable over a long
period, easilycleaned, reasonably priced, and readily available.
The fabricsfor which these garments are made tend to be plain or
twillweave fabrics in 100 % Polyester, 100 % cotton, polyesterl
cottonblends, polyest erlmodal blends, 100 % nylon, and
nylonlPolyester blends. All of these fabrics have features
toracommend them, notably the comfort and good launderingattributes
of cotton and the toughness and durability of thesynthetic
fibres.The third category of protective clothing is the type of
clothingthat affords protection to the wearer against materials
oragencies that would Cause some degree of harm to the person.In
this category the clothing forms a barrier between the personand
the hazardous environment. The range and Character ofthe
potentially dangerous environments against which, or inwhich, some
form of protection is needed is wide, and includesthe following:a)
Heat and flame: The requirements here range from clothingfor
situations in which t he person may be subjected to anoccasional
dose of a moderate level of radiant heat as patt
of his normal working day, to clothing for protection
insituations in which the person may be subjected to severeradiant
and convective heat and to direct flame e.g. firemensclothing.b)
Chemicals: In some cases the technical requirements here
may be severe, as when the person is to be protectedcompletely
against accidents with severely corrosive andtoxic chemicals that
even in very small doses would be veryhazardous.c) Weather: The
protection of the person against cold weather,probably associated
with wind, rain or Snow, presentscomplex Problems; much pr ogress
has been made but theProblems have not yet been completely
solved.d) Electrostatic hazards: Static electricity on the clothing
andbody, as weil as being a nuisance (by causing clothes to clingto
the body and giving rise to unpleasant electrical shocks)is also
potentially destructive (in for example Computermanufacturing
processes) and hazardous ( Sparks causedwhen static electricity is
discbarging may Cause fires andexplosions). There is therefore much
current interest in thedevelopment of anti-static materials.e)
.Mechanical hazards: Protection against bullets and othersmall
projectiles is usually achieved by the use of layers offabric made
fr om fibres of high mechanical Performance(usually aramid or high
tensile nylon). Protection againstbeing tut by knives, chopping and
cutting devices, sheetglass, etc, is best achieved by metallic,
.chain mail, typesof fabric, or again by aramids.9 Surveillance (in
the military context): The person needs to beprotected against
detection by Optical and infrared devicesby suitable forms of
camouflage.In each of the above areas the requirement is to protect
theperson against the environment. In one example of protectivework
clothing, however, the purpose is to protect theenvironment against
contamination by the person: this is theincreasingly important area
of ,clean room clothing.In this Paper, protection against heat and
flame, chemicals, thewesther, static electrical Problems, and the
special requirementsof clean r oom protection are discussed.
26
In general t here are no insuperable difficulties in the
protectionas such of a person against most aggressive agencies.
TheProblems, and they are many and severe, are to combine
anadequate level of protection with sufficient comfort
and.wearability, and reasonable economic aspects (i.e. the tost
ofthe new article and the costs of cleaning and
maintenance).Problems associated with the comfort and wearabiltiy
of theprotective garment or garment assembly tan be
particularlysevere. In the first place the assembly may be so
thermallyinsulative and water vapour impermeable that the wearer
mayrapidly begin to suffer discomfort and heat stress. His
bodytemperature may rise and he may become wet with sweat:Problems
associated with the dispersal of liquid sweat from thebody tan be
particularly severe and are akin to similar Problemsin various
types of active sportswearIn addition to the thermal discomfort
there may be majorProblems associated wi th diminished dexterity,
tactility, andmobility. A further important considerat ion in the
design ofprotective apparel, in addition to the protective
capability,comfort, and economics referred to above, are such
factors asstyle, aesthetics, and the social, psychological, and
culturalaspects. Even when the protective capability needs to be
veryhigh (e.g. in situations of real hazard), it is still necessary
thatthe wearer should feel correctly and attractively dressed in
thecontex of his Company and social Status.
C. Protection against Heat and FlameThe need for protective
apparel for fire-fighters and the like isobvious, but quite apart
from this there are a number ofindustries (Tab. 1) in which the
hazards from heat in one formor another, and flame, ar e such an
integral part of the job thatthe worker needs to wear protective
clothmg more or lesscontinuously.
Table 1: Hazarchs ompaths tmessiMng protectionagainst flame and
heat- -
; Industry Flaue Thermal Contact (a) Heat (b)Foundry(steel
manufacture / // //metal casting,forging, glass)
-Engineering(welding, cutting, /boiler werk)
// /
011, gas, Chemical / 0 0
Munitions and / 0 0pyrotechnics
-Aviation and space / 0 0
-Military // / /
-
// = major hazard; / = subsidiar y hazard; 0 = minor hazard(a) =
,Thermal contact may involve hot objects or molten metal(b) = ,
,Heat may be either radiant heat or convective heat
To protect against these hazards, the person, depending
Oncircumstances, may require overalls, jackets, aprons,
leggings,gloves, and hoods that are made of a material that is in
somedegree heat-resistant and/or flame-resistant, and
fabricscomposed of a range of types of fibre have been and are
beingused for this purpose. In some cases t he heatlflame
protectiveapparel is worn over the person5 normal clothing. In
othercases, usually involving more severe hazards, the heat
protec-
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tive fabric is merely t he outer .shell of a fabric assembly,
theinner layers of which are usually meant to reinforte the
protectivefunction of the Shell, but may in addition be required to
performsome other function e.g. to absorb sweat. In deciding on
thenature of a heat protective assembly, the four factors
thatinfluence Performance are the total amount of thermal
energyabsorbed by the outer garment, the rise in temperature of
thegarment caused by the absorption of heat, the effects of
thisheat absorption on the material itself, and the rate at which
heatfrom the hot outer garment is transmitted through to the
innergarments and to the skin.Table 2 lists various types of fibre
that are being used at presentin the outer fabrics of heat
protecive garments. Some fibres are.flame-ret ardant, i.e. will not
ignite or burn, but will melt if thetemperature attained is high
enough, causing a hole to appearin thefabric; loss of protection is
then coupled with the possibilityof molten polymer sticking to the
body. These fibres are clearlynot suitable for heaffflame
protective apparel and are notincluded in Table 2.
Table 2
l By way of example only. Does not imply endorsement over
othermaterials having a similar function.l * Development carried
out at IWS.
The fibres that are included in Table 2 are fibres that will
alsonot ignite or burn, but that will in addition form a coherent
char(without shrinkage) when heated sufficiently to decompose
thematerial; thus fabrics made f rom these fibres will continue to
be,in the charred form, a protective barrier to heat and flame.
1. cottonBy itself, cotton is readily igni ted and burns
rapidly. However,the finishing treatments listed in Table 2 are
very effective inproviding flame retardancy. The treated cotton in
each caseforms when heated a carbonised char which is
reasonablyintegral and physically stable and thus provides
continuingprotection to the undergarments and skin. FR cotton is
widelyused in heat and flame protective clothing.
2. woolWool is significantly flame-retardant in its natura1
state, and thelevel of Performance tan be further i mproved by the
Zirprotreatment. The thermal protection provided is of a high
Order,probably assisted by the hairy surface of wo01 fabrics,
whichreduces the degree of contact of the outer fabric with the
fabricbelow or the skin. Wool fabrics find extensive use in
protectivegarments for foundry wokers, since splashes of molten
metaldo not adhere to the garment. However, as is weil known,
wo01presents Problems in relation to vigorous laundering, and
wo01fabrics t an be uncomfortably hot to wear at the fabric
weightsneeded for thermal protection.
3. viiThe finishing t reatments that confer FR properties on
cotton arealso reasonably effective on viscose fabrics. However,
alternativemethods have been developed whereby FR additives
(e.g.Sandoflam 5060 from Sandoz Ltd.) are incorporated into
theviscose spinning solution. lt is claimed that these inherentl
yflame-retardant fibres offer problem-free processability,
nophysiological Problems, low toxicity of fumes when Ignited,
highresistance to yellowing, good light fastness, no melting
orshrinkage on exposure to heat or flame, and good
resistanceagainst various molten metals.In practical applications
in protecti ve clothing, blends with othertypes of fibre are
important, for example FR viscose/wool blendsand FR viscoselaramid
blends.
4. Aramld (aromatic polyamide)Aramids tan be classified into two
categories:a) the aramids in which the aromatic groups are linked
in themeta Position and which have high thermal resistance
(Nomex,Conex. Apyeil), andb) the aramids in which the aromatic
groups are linked in thepara Position and which have, in addition
to heat resistance, highPerformance mechanical characteristics e.g.
Kevlar, Technoraand Twaron.Aramids are very resistant to quite high
temperatures (e.g. 1000hours at 250 C has relatively little effect
to tensile properties).They begin to char at about 400 C, with
little or no melting.In general it is the meta-aramids that are
used in heat protectiveclothing; para-aramid fibres are too stiff
to be used on their ownin clothing and are only used as a minor
component in someinstances to improve mechanical properties, e.g.
for use inintense heat, Nomex Ill is available: this is a blend of
Nomexwith a small amount of Kevlar included to lend
greatermechanical stability to the char. (Kevlar is produced in two
forms,Kevlar 29 and Kevlar 49; the former would be the type usedin
heat protective apparel).Garments made from meta-aramids are hard
wearing,comfortable, and easily launderable. The fibres are
expensive,but tan often be safely blended with eheaper FR fibres
(e.g.FR wo01 and FR viscose). Karvin (Du Pont), for example, is
ablend of 30 Vo Nomex, 65 % FR viscose, and 5 00 Kevlar).
5. Polyamide-imidesKermel fibre is chemically related to the
aramid fibres (thearomalic groups on the polymer chain are linked
by imidegroups in addition to amide groups) and is similar in
propertiesto the meta-aramid fibres. Again, the fibre beg,ins to
char atabout 400 C and has good mechanical propertles at
elnvatedtemperatures.
6. PolyimidsPolyimlde fibres have excellent t hermal stability
and a highdecomiposition temperature (decomposition begins at
about
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400 C). Polyimides tan withstand constant use at tempera-tures
up to about 2.50 C. Polyimide fibres make f abrics thatare
comfortable to wear, and tan be used either on their ownor blended
with, for example, FR viscose.
7. PolybarKlmidamlePBI fibres combine excellent resistance to
high temperatureswith acceptable textile properties; fabrics made
fr om PBI havea high moisture content, and are claimed to have a
good,,handlel PBI fibres give excellent protection against
fire,retaining t heir flexibility and exhibiting no afterglow. They
willwithstand long term exposure at temperatures up to 300 -35OC:
rapid degradation begins at about 450 C in air, andextensive
pyrolysis only begins at about 550 C. The charproduced is intact
and pliable.
9. Phenoic (Novoioid)Kynol is a chemically unique
flame-retardant and heat-resistantfibre obtained by spinning and
post-curing a phenol-formaldehyde resin pre-condensate. The fibre
is soft andgolden-coioured. When strongly heated or placed in an
openflame Kynol fibre is carbonised with little or no evolution of
toxicgases or smoke. The lack of strength and poor
abrasionproperties preclude its use in many apparel applications,
butKynol fibres do find use in protective apparel, often blended
withother fibres (Nomex, FR viscose) t o upgrade its
mechanicalproperties.
The melting Point of Ryton fibres 285 C is. high, contributingto
their good high temperature stability. Although a good FRfibre, it
is probably its Chemical resistance, coupl ed with its abilityto
retain its physical properties under very adverse conditions,that
will determine its uses in protecti ve clothing, with
flame-retardant and heat-resistant properties playing a subsidiary
role.
10. Polyacrylate (Inidex)A Cross-linked copolymer of acrylic
acid and acrylamide; thisfibre has been developed principally for
use in nonwovens, butits heat resistance, difficulty of ignition,
and the stable char thatit forms (with no shrinking) when thermally
degraded suggestits suitability for some forms of heat-protective
clothing. However,the durability of fabrics made f rom this fibre
may not beadequate for some apparel uses.
11. Semi-carbonThese fibres are produced by the thermal t
reatment (,,semi-carbonisation) of either viscose fibres (Asgard
and Firotex) oracrylic fibres (the other f our fibres in this
category in table 2).The acrylic fibres tan be treated in fibre
form; the viscose fibresmust be partially carbonised in the fabric
form. Both types offibre have excellent heat stability, and do not
burn or melt; afterexposure to flame, there is no afterglow and the
fabric remainsflexible. In these r espects they are ideal for
protective clothingagainst flame.However, the abrasion resistance
of these fibres is onlymoderate, which would tend to militate
against their use in sometypes of apparel. Blends with other FR
fibres may be used toimprove the mechanical properties. A
disadvantage is that thesemi-carbon fibres have high thermal
conductivity and are non-reflecting. To minimise the transfer of
radiant heat it may in somecircumstances be necessary to metallise
the fabric and to wearinsulating underwear. A further, aesthetic,
disadvantage is thatsemi-carbon fibres are of course always
black.
28
12. PTFEFibre from PTFE are very resistant t o heat and flame:
majorthermal degradation only begins at about 400 C. The
LimitingOxygen Index is as high as 95. The use of fabrics made
fromthis fibre in protecti ve clothing is, however, limited by:a)
the modest strength and durability of these fabrics andb) the high
tost of PTFE.
13. GlassFabrics made fr om glass fibres are used in some types
ofprotective clothing, but suffer from the disadvantages of:- poor
abrasion resistance,- reiatively poor resistance to high
temperatures, and- difficulties in the manufacture of the
garments.
14. AsbestasAlthough there are the weil-known health problems
associatedwith the use of asbestos, there is no doubt that asbestos
textileshave excellent FR and HR properties (they will, for
example,withstand prolonged heating at temperatures up to 500 C).
lthas been claimed that aluminised asbestos fabrics are the
onlyones that tan be used in complete safety in situations
whereflame impingement onto the person is likely.In consideri ng
relative ,,non-flammability , it is interest ing tocornpare
limiting Oxygen index (LOI) values of the various fibreslisted in
Table 2. The LOI is the minimum percent age of Oxygenin the
atmosphere necessary for the material to ignite and burn.Table 3
lists these values.
Table 3: Limiling Oxygen Index
PTFESemi-carbonPB1PolyimidePolyphenylene
sulphidePhenolicAramidCotton (treated)Wo01 (untreated)Cotton
(untreated)
9550
38 - 4636 - 38
3430 - 3425 - 3429 - 34
2419
Interesting information comparing fabrics made from the
variousFR and HR fibres, and fabric constructional factors
affectingheat protective behaviour is available in the literature,
forexample by Schoppeef, Krasnyz, and Young Moo Lee andBarkers.As
rndicated above, some types of fire protectrve apparel consistof
more than one layer of material; two or even three layers offabric
(perhaps assembled as one garment, or perhaps as twoor three
separate garments) may cover the ,,every day clothes(e.g. the coat
or shirt) of the wearer. The outer layer alwaysconsists of one of
the heat- and flame-resistant materials listedin table 2, the
function being to form a coherent thermal Screeneven when the heat
flux concerned is sufficient to darnage thefabric. In general, the
thicker and heavier the fabric, the greaterthe protection afforded;
air spacing in multi-layer assemblies isalso important in
determining the insulation4,s,s.The functi on ofthe underlayers is
mainly to insulate the body trom the potentiallyvery hot outer
layers. In somefire protective clothing assemblies,a ,,vapour
barrier may be included, e.g. a neoprene-coated
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Nomex fabric, often between the outer Shell and the next
fabriclayer; its purpose is to prevent water in the outer ,,Shell
fabric,vapourised by the heat, from being forced inwards and
causingscalding. At the British Textile Technology Group, work has
beencarried out on the properties of 34ayer composite
fabricassemblies; in these assemblies the outer layer is, for
example,a flame-retardant cotton or aramid fabric, the core is a
thermally-bonded .highloft nonwoven fabric made from a
heat-resistantfibre such as an aramid (to provide the thermal
insulatronneeded), and the liner is a fabric with good tactility
and comfortwhich also protects the high-loft core from mechanical
darnage.With all heat- and flame-protective fabrics, whatever the
material,the question of cleaning is important for two reasons.
First, forconsideration of hygiene: the wearers of heat protective
clothingoften sweat profusely, f rom a combination of the
necessarilyinsulative properties of the apparel, of the often hot
environment,and of the fact that the wearer is usually carrying out
some formof physical work. Second, contaminants may weil have
adeleterious effect on the flammability and heat-resistantbehaviour
of clothing. Frequent cleaning of heat-protectiveapparel is
therefore necessary and the technical implications ofthis in
relation to the design of heat-protective clothing for aparticular
application should always be borne in mind.Two other aspects of
heat- and flame-protective clothing needto be discussed in brief.a)
Use oi Reflective SunacesAn increase in the thermal protection
afforded by a fabricagainst radiant-heat tan be obtained by the use
of metallic(usually aluminium) layers on the clothing assembly.
Theapplication techniques include the use of aluminium foiladhered
to the outer fabric of the assembly, or the vacuumdeposition of
aluminium directly onto the fabric. One Problemwith these highly
heat reflective Systems is that they becomesmuch less effective if
the metal becomes soiled. AnotherProblem in some circumstances is
the low transmission ofPerspiration vapour, particularly with the
aluminium foil (thisshould be less of a Problem with the vacuum
coated materials).There may weil also be difficulties in cleaning
the garments.There is no doubt, however, that the Thermal
Protective Index(the time taken for the temperature at the back of
the heatirradiated fabric to rise by 25 C) is much increased by the
useof these highly reflective layers 6,7. Aluminized fabrics are
veryeffective for use in the metals i ndustry, because splashes
ofmolten metal tend to be ,,shed better by the aluminium layerthan
by textile materials.b) Effect of Moisture on Thermal ProtectionThe
effect of fabric moisture on the thermal insulation propertiesof
heat resistant fabrics deserves special mention. The Situationis
complex. On the one hand, water i ncreases the thermalcapacity of
the fabric, but on the other hand, the thermalconductivity of wet
fabric is higher t han that of the same fabricdry. lt has been
showns that with a mixture of convective andradiant heat of
moderate intensity the thermal insulation may beimproved. With
intense radiant heat alone, thermal protectionis reduced.
D. Chemical ProtectlotlWith all forms of protective clothing,
there are wide variationsin the level of the hazard against which
protection is sought. Thisis particularly so in the case of
protection against chemicals. Atthe lowest levels of Chemical
hazard, the garments need onlybe a little more protective than
those i ncluded in the secondcategory of work clothing outlined on
page 5 above, i.e. theyconsist of uncoated cotton, Polyester,
nylon, or blended fabrics,usually in a closely woven construction
and sometimes with awater-repellent finish.This part of the Paper
is not concerned with this Iow level, lightduty, requirement, but
deals with protection against accidental
contact with chemicals that pose a real threat to the life and
wellbeing of the wearer. In most cases the aim is to protect
theperson against accidental splashes of chemicals, but wherevery
highly toxic materials are involved, protection againstvapour and
gases must also be provided.In these ,,heavy duty protective
applications, the garments atone end of the range may consist
merely of aprons of varioussizes and designs; at the other extreme
are garments that totallyencapsulate the body, limbs, and head.
These latter garmentsare largely made from coated woven fabrics
(often nylon orpolyester), although for many applications
spun-bondedmaterials, e.g. Du Ponts Tyvek, often coated with a
polymer film,are gaining increasing acceptance. The protection
afforded bythe coated woven fabrics is largely the result of the
polymercoating. In some applications, indeed, it is possible to
makeprotective garments from unsupported polymer film, or apolymer
film on a light scrim, but particularly for heavy dutyapplications
it is clearly desirable that the polymer film shouldbe supported on
a tough underlying fabric, for increasedstrength and
tear-resistance.Polyvinyl chloride-coated nylon and Polyester
fabrics ar e still themost widely employed materials for heavy duty
protection, butother polymer coatings, e.g. natura1 rubber,
nitrile-butadiene,neoprene, and butyl rubbers, Hypalon
(chlorosulphonatedpolyethylene), polyurethane, and Viton
(afluoro-rubber) are alsoemployed, depending upon the application
and the level ofprotection required.In designing or selecting a
protective garment for a particularapplication, several factors
need to be taken into consideration:- the effect of the Chemical
agent or agents on the physicaland Chemical properties of the
materials from which theprotective clothing is made;- the rate of
permeation of the Chemical agent or agentsthrough the materials of
the clothing, e.g. through the coatedfabric constituting the main
part of the protective suit;- the deagn of the garment in respect
of the seams, zippers,and other places where different materials
join, e.g. visors,gloves, boots, exhaust valves (it is obviously
essential thatthese items are completely sealed);- the tost of the
protective assembly.lt is perhaps in the area of permeability to
chemicals that mostdifficulties arise, in spite of their apparent
Jmperrneability; it isa fact that most polymer films have a
significant level ofpermeability to many toxic chemicals; some
polymer fi bres mayin fact become quite highly swollen, if immersed
in liquidchemicals, an indication of a high level of Chemical
affinity. Afteran initial Stage, during which the coated fabric
appears not totransmit a particular Chemical, there is a
,,breakthrough Pointfollowed by a rise in permeation rate, often
subsequentlyachievirlg a steady rate of transmission. If this
steady rate issufficierltly low, depending upon the toxicity of the
Chemical,then the garment will be safe to wear against that
particularChemical. Otherwise, there may weil be a hazard of which
thewearer would be unaware, because of the sense of false
securityengendered by the ,,impermeable nature of polymer films.
Ifthe Chemical is very highly toxic, then even a very l ow rate
ofpermeation is potentially damaging, and in these circumstancesthe
provision of an inner garment or layer containing anabsorbent
material, such as active carbon, must be considered.If the igarment
is intended to protect against a number ofchemicals, perhaps at the
same time, then the nsk factor isclearly greater; t he effect of
each component may besynergistic. lt must be emphasised that no one
material will resistattack or Penetration by all chemicals, and in
somecircumstances, therefore a number of suits made from
differentmaterials will need to be available to provlde
adequateprotection. There is a obvious need for as much systematic
andcomprehensive data as possible on the permeabllity of
polymercoatingis to chemicals; much has been and is being done,
butmore nleeds to be done.
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Whatever the permeability of the normally- used polymercoatings,
as listed above, to Chemical liquids and vapours, thereis no doubt
that the rate of transmission of water vapour by thesecoatings is
low. Thus, the thermal comfort of garments madefrom these coated
fabrics is low, particularly if the garmentneeds to be worn for
long periods, when heat exhaustion of thewearer may eventually
occur. Also, garments of this type areoften rather cumbersome and
may tend to restritt the mobilityof the wearer. For many purposes,
in heavy duty high riskapplications, this lack of comfort is part
of the price that needsto be paid for sufficient protection, and it
is difficult to foreseecomplete solutions to the Problems involved,
exept possibly fortotal encapsulation suits in which the air is
exchangedcontinuously by air pump Systems, or the use of
water-cooledundergarments, techniques that are both intrusive to
the wearer.However, as indicated above, spun-bonded polyolefin
fabricsare finding increasing use in certain applications;
garmentsmade from spun-bonded fabrics are lightweight and
relativelycomfortable (for protection against liquid splash, Tyvek
tan belaminated to polyethyl ene or to Dow Chemicals Saranex
PVDCfilm).One approach to improve the comfort of Chemical
protectivegarments, under investigation at the British Textile
TechnologyGroup, is the use of fabrics coated with .breathable
non-porouspolyurethane, suitably modified to confer increased
Chemicalprotection. These breathable polyurethane coatings
aredesigned primarily for use in rainwear and are discussed againin
the next section of this Paper; the purpose of our current workis
to include in the polyurethane structure Chemical groups thathave
specific Chemical-protective functions, whilst not detractingtoo
much from the high moisture-transmissive capabilities of
thepolymer.Another approach to the reduction of the dangers of
heatexhaustion in Chemical protective clothing is the use of
awettable cover over the protective garment; evaporation of
waterfrom the wet outer garment extracts heat from the
protectiveassembly and thus cools the System. Evidente existss that
thetoleration time of a Chemical protective garment is
increasedsignificantly by the use of a wet cover, although there
aredifficulties in operating the method, e.g. it is obviously
necessar yto ensure an adequate water supply and a means of
applyingthe water to the outer garment in a continuous manner.
E. Mkather ProtectionThe protection of the person against severe
weather conditionsinvolves two distinct, although inter-related,
aspects: protectionagainst cold and wind, and protection against
rain and Snow.Clothing Systems to protect against t hese agencies
essentiallyconsist of two components. First, an inner component of
materialto insulate the body thermally; this insulating component
mayitself consist of several layers e.g. underwear, thick
pullover,quilted liners, or high pile liners. Second, an outer
componentto protect the insulating l ayersfrom direct contact with
wind, rain,or Snow. This outer fabric must obviously therefore be
windproofand, in wet conditions, also waterproof. lt is not
necessary thatthis outer cover should be thermally insulating.As
regards the design of the thermally insulating layers, the
keyfactor is that the fibrous or polymeric structures in these
layersshould be reasonably thick and entrap a large volume of
air.Still air is an excellent thermal insulant and the thermal
insulationof such high bulk structures is directly proportional to
theirthickness. There are at present four main types of
thermallyinsulative structure: thick, open-structured, knitted
fabrics; highpile fabrics (i.e. .furry materials); quilted
structures containingeither featherl down mixtures or synthetic f
ibre fillings; and highlyporous, flexible polymers.Table 4 gives
information on the thermal insulative propertiesof these var ious
types of structure. The similarity in the thermalinsulation values
per unit thickness is striking, and confirms theover-riding
importante of the thickness of these materials in
30
achieving good thermal insulat ion. However, a comparison ofthe
vaiues of thermal insulation per unit weight reveal
largedifferentes between the different types of structure.
Certaintypes of microfibrous nonwoven or wadding material
(e.g.Jhinsulate, made by the 3M Company) are claimed to
possessvalues of thermal insulation per unit thickness that exceed
thevalues given by other, more conventional, fibrous structures;
itcould be that air trapped in fine fibrous structures is
subjectedto even less convective movement than air trapped in
normalfibrous structures, and the thermal insulation may be higher
forthat reason. I n view of the importante of the entrapped air
indetermining the insulation value of a textile structure, it is
clearlyessential that the structure be kept dry; it is necessary
thereforethat the outer fabric or garment be waterproof.
Tabls 4: Thermal insulation (tog) vakres for various
matedals
Cantinuous filamentpolyester quilted fabricResin-bonded
staplepolyester quilted fabricSliver-bit acrylic high
Sliver-knit Polyester high
Clcsed cell expandedpolyethylene
iog/cm thicknessof material
2.6
2.1
2.4
2.3
2.2
2.5
Tagslunit weight afof material
(100 x tags x m2/g)2.1
1.5
1.2
0.7
0.55
0.6
l The tog value of a fabric is equal to ten times the dif
ferente intemperature between its two faces when the flow of heat
is equalto 1 wattlmz. The values listed in the table are calculated
from val ues9iven by C. Cooper: Textiles, Vol.8, No.3, p 72
lt is, in fact, the outer cover fabrics of foul weather clothing
thatin recent years have seen most development, in relation to
therequirement for high wate! vapour permeability combined withgood
resistance to Penetration by liquid water (e.g. rain). Evenin cold
weather the human body perspires and often (duringvigorous
exercise) will exude large amounts of liquid sweat. ltis ihus
highly desirable that the outer layer of the fabricassembly,
although rain protectiveshould also be water vapourpermeable
(.breathable); lack of such ,,breathabilit y willpromote build-up
of liquid water within the garment assembly,as lperspiration
condenses and as liquid sweat wicks outwardsfrorn the body; this
lowers the thermal insulation properties ofthe assembly, since
water is a better conductor of heat than stillair. Research in the
early 1940s to solve the Problem of water-proofness combined with
breathabilit y led to the developementof ,Ventile fabrics (top
quality, closely woven, water-repellant-finished, cotton fabrics),
and indeed these excellent fabrics arestill employed in certain
demanding Situation& and areexperiencing a resurgence of
interest for leisurewear. Morerecent developments have, however,
concentrated onimprovements in the water vapour permeability of
polymer-coated fabrics. Table 5 lists the main breat hable
waterproofcoated fabrics on the market at present.The protective
polymer layers in these fabrics fall into two maincategories:0
Mcroporous Coatings and Film LaminatesIn tlhese materials the
fabric coatings are made f rom a basicallyhyclrophobic polymer and
are rendered permeable to moisturevapour by means of a network of
micropores. In the case of
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Table 5: Commsrcially available ,breathabk,
waterpradfabricsFabric OPfabric coating TYPE
Microporous P.T.F.E.Microporous polyurethaneHiC~OpOrOS
polyurethaneMicropomus polyurethaneNic~oporous
palyurethaneNon-porous, hydrophilicpa1yurettlaneNon-porous,
hydrophillcpo1yester
Gore AssociatesTonyGarrington
PerformanceFabricsPorvairtlelsaFabrics based 0polyurethane mpplied
byBaxenden Chemical Co.Eb
Gore-tex the polymer film is PTFE and is laminated between
twofabric layers; in the other four cases the polymer film IS
apolyurethane, and is direct or transfer coated onto a knitted
orwoven fabric. Although these microprous structures are
veryeffective in use, the pores may tend to become clogged
withcontaminants and thus frequent cleaning may be needed.
2) Non-porous, Solidl FirnsIn these materials the high water
vapour permeability isachieved by the inclusion of hydrophilic
Chemical groups intothe polymer structure. The development of these
materialspresented severe Chemical Problems, because in general
thetypes of Chemical group that are hydrophilic are the types
thatCause unacceptable stiffening of the polymer due to
stronginteractions between these groups on adjacent polymer
chains.Other strongly hydrophilic polymers may be too susceptible
toliquid water i.e. they would either dissolve or swell
severely.Solutions to the Problem have been developed: for example
t hebreathable polyurethane coating Syst ems (Witcoflex
Staycool),and the breathable Polyester film laminate (Sympatex).
Thesenon-porous types of breathable coatings and films are
eithertransfer-coated or laminated onto the base fabric or
directcoated. Table 6 summarises data obtained on the water
vapourpermeability of coated fabrics, 100 % representing the
highestpermeability currently available for a waterproof fabric and
thevalue for a particular material being given as a percentage
ofthis. lt has been argued that values of over 80 Yo rate as
highlybreathable in relation to body comfort, and those between 50
Yoand 80 % rate as moderately breathable in the context of
itsfunction primarily as a weatherproof material. The wide r angeof
values covered within each group is partly the result ofdifferentes
in the various polymer films within each group butis also partially
(and perhaps mainly) the result of variations inthe base fabric
(fibre type, openess or tightness of construction,quality of the
coating process). This range of Variation isparticularly high in
the non-porous, hydrophilic, polyurethanematerial% samples have
been tested that range from highlybreathable to
less-than-moderately breathable (Tab. 6).
Tabls 6: Breathability of outwear fabrics
Name TYPe ManufacturerLurotex AZ5 Polyamide derivative;
non-ionic BASFSilige *PE Puaternary ammoniu m campaund; cationic
BASFze1ec DP Dispersion af organic pol Ymer.3; cationic DU
PontNonax 1166 Modified synthetic resins: cationic Henkel
F. Electrostatic ProtectionThe generation of electrostatic
charges on clothing and on thebody tan lead to Problems of five
types:- Static electricity, at Potentials on the body over about
2000Volts, tan lead to unpleasant shocks when the electricalCharge
on the person is discharged to earth (this tan be
dangerous because it may, for instance, Cause the personto drop
articles being held).- The attraction between the Charge on the
clothing and theincluced Charge of opposite polarity on the body
tan Causethe clothing to cling to the body resulting in a feeling
ofdiscomfort and an unsightly disturbance in the drape of
theclothing.- Thle attraction of small particles, e.g. dust,
powder, and lintto the surface of the clothing.- Darnage to, or
destruction of, electronie equipment orcomponents, particularly
during manufacture.- Fims and explosions caused by the electrical
spark thatoccurs during discharge of the Charge on the body;
theenlergy in the spark may weil be above the minimum energy
required to ignite certain gases and vapours, and also
certainpowderso,tl. Table 7 lists some industries and situations
inwhlich static electricity tan Cause severe Problems of one ofthe
above types.Table 7: Areas in which stak electricity tan cause
pmblsms
Hospital operating theatres and wardsLiquid refuellingPaint
spraying Operation3Solvent and fuel productionProduction of
explosivesOil rig operationsElectronics manufacturing processes
For these reasons a great deal of effort has in recent years
beendevoted to the development of fabrics that are antistatic
inCharacter i.e. fabrics in which the static electrical Charge is
eitherconducted away or .neutralised in some other way.
Antistaticbehaviour of this type tan be achieved by the application
ofantistatic finishes to the surfaces of the fabric concerned.
Thesefinishes reduce the static electrical Charge produced on
thefabric in a particular Situation by making its surface in some
waymore electrically conductive. With some of the finishes
thisincreased conductivity is achieved by the fact that the
finishtends to absorb moisture f rom the atmosphere and at the
sametime supplies ions to the fibre surface, which
combinationreduces the electrical resistance of the fibre. Table 8
lists anumber of antistatic finishes t hat are currently
available.
Tabk 6: Antistatic finishesr Fabric Relative watervapour
permeabilityWoven fabric (microfine fibre)
Conventional polyurethane coatedOther conventional polymer
coated
Table 9 gives examples of results indicating the magnitude ofthe
reduction in surface r esistivity that tan be obtained by theuse of
antistatic finishes listed in Table 812. The range of valuesat each
level of add-on is an indication of the actual range of
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LENZINGER BERICHTE August 1989
values given by various finishes, and indicates the
widedifferentes in the effectiveness of the finishes.
However,although high reductions in surface resistivity tan be
obtained,the agents available at present are at least partially
removedfrom the fabric by washing or dry cleaning, as evidenced
bythe fact that the sutface resistivity of the fabrics are
substantiallyincreased by the cleaning, generally to a value
between thosefor the unfinished fabrics and the fabrics that have
been finishedbut not washed. In some cases, the resistivity of the
washedSample approaches that of the unfinished fabiic.
Tabis 9: Log surfsca tesktlvlty (Ohm) st 95 % r.h.r abric I
add-o of finish0 2 4
Polyester - 12.7 7.2-11 .o 7.0-9.2Nylon 66 14.0 7.5-9.2
6.7-9.1Polyester-cotton 67/33 10.65 7.4-9.5 7.0-9.0Gotton 10.4
7.6-9.0 7.4-9.0WO01 11.8 8.2-11 .5 7.9-10.9 1.5-9.6
If a permanent antistatic effect is necessary, the most effecti
veway of reducing proneness to static charging is by inclusion
inthe fabric of a percentage of an electrically conducting
fibre.These fibres may be in staple form and be incorporated
intothe yarn by blending in the normal way with the main fibre,
orthey may be in continuous filament form.There are three main
types of inherently conducting fibre. Table10 lists examples of
each:a) Synthetic fibres (usually polyamides) that contain
internaladditives ( humectants) that increase the hydrophilicity of
thefibre and fibre surface; the fibre surfaces consequentlycontain
more moisture than is the case with StandardPolyamide fibre, and
thus they are better conductors ofelectricity. These additives are
introduced at the melt Stageand may be copolymers of ether, ester,
and amidemonomers. A Problem with these fibres is that they
areineffective at the lower humidities, for obvious reasons.b)
Fibres that contain conduct ing additives, either internally oron
the fibre surface.c) Metallic fibres and yarns.The .humectant
fibres listed in Table 10 (a) are usuallyemployed in substantially
100 % form i.e. the antistatic nylonfibre is simply used in instead
of the normal nylon fibre. Theconducting fibres, examples of which
are listed in Table 10 (b)and (c), are normally employed in small
percentages; of theOrder of 1 % conducting fibre is adequate for
many pur poses,but in some applications up to 5 % may be necessary
foracceptable performante.
Table 10 a): Polyaddes with intemal antistak additivesName Nylon
type YanufacturerEnka comfort 6Lilionantistat 6Ultron 66Cadon
66
EnkaSnia FibreMonsantoMonsanto
Table 10 b): Synthetic fibes with conducting additives
Epitrapic
Rhomjiastat s
Enk~nstat
Antro 111
X-StatiC
TYPESbeath-core bicomponent fibre,with carban pa~tioles
dispersedin the surface 1ayer
Polyamide staple f ibre with aooating of topper
sulphidePolyamide fi bre containingdispersed carbo particlesAntron
trilobal yar containinground filanents with a carbon-containing,
conducti ng, corePolyamide filament coated uitbmeta1
ICI Fibres
Rhone-Poulenc-Fibre
Enk=
0 Pont
ROhrn h Haas
T-ab& 10 c): Metslllc fiis and yams-Name Type
Manufacturer-Bekinox Staple op continuous filament N.V. Bekaert
SA
steel fibreBrunsmet Staple or continuous filament Brunswick
Technetics
steel fibreBekrtex Polyamide yar containing N.V. Bekaert SA
Bekinox fibreBrUiSlO Polyamide yar containing Brunswick
Technetics
Brunsmet fibre-
G. Clean Room ClothingThe lprovision of clothing for use in
clean rooms, to prevent therooTn from becoming contaminated with
particles from theperson, is one of the most important areas of
development inthe field of workwear. The levels of freedom from
part iculatematter required in clean rooms are becoming ever
higher,particularly in the electronics manufacturing industry, and
so thePerformance requirements of the apparel to be worn in
theserooms becomes ever more demanding.Clean room fabrics need to
have combinations of properties t hatare particularly difficult to
achieve, even compared with otherforms of protective clothing.1)
The generation of particles by the garment when it is flexedor
abraded in use must be of an extremely low level. This
alreadysevere functional requirement is becoming even more
severebecause of the realisation that, at least in the
electronicsindustries, it is the small particles (including
sub-micronparticles) that are of major importante. One
difficultyencountered in attempting to design a fabric and garment
oflow propensity for particle generation is that the nature
andorigin of the very small particles is not fully understood:
theyare probably generated in part from mechanical degradationof
the fibres during flexing and abrasion, but a good proporti onmay
be merely particles from the atmosphere that have settledon tihe
fabric and garment during manufacture (perhapsattracted by static
electrical charges on the fabric). Present dayfibre, yarn, and
fabric manufacturing techniques, howeversophisticated, are simply
not suitable to be carried out in cleanroomls; and the
effectiveness of removing very small parti clesby washing or dry
cleaning is not certain.2) The fabrics and garments must be very
good barriers to thepasaege of particles, even of sub-micron
size.3) The fabrics need to be of low electrical resistivity, and
thegarrnents need to be earthed during use, to prevent the
build-up
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of static electricity. This aspect is particularly important in
the b) the development of methods for the wearer of
protectiveelectronics manufacturing industry. clothing to be able
to adjust at will the properties of the4) The fabrics /garments
need to be comfortable to wear over garnnent assembly to match
changing environmentallong periods, principally in relation to the
transmissi on of circumstances in which he finds himself (e.g.
changes inPerspiration but also in relation to the ,,handle and
.feel of the ambient weather conditions).fabrics involved. It is
certainly possible that new polymers and fibres will be5) The
garments must be economically viable i.e. reasonably developed that
will increase significantly the level of functionalpriced on
initial purchase and capable of being worn and behaviour of
protecti ve apparel . But, bearing in mind thelaundered for a large
number of wash-wear cycles without preseni: state of knowledge of
the chemistry and physics of fibresdetriment to any of the propert
ies listed in 1 - 4 above. and polymers, any major breakthrough
into completely newClean room garments made f rom a wide range of
fabric types types of material i s considered unlikely in the
immediate future.are at present in use. The most effective fabrics
include tightlywoven, synthetic fibre filament fabrics, which are
oftencalendered to improve the barrier properties, and various
kindsof spun-bonded fabrics. Coated fabrics are being
increasinglyemployed, because of their ideal particle barrier
properties, anda current project at the British Textile Technology
Group isconcerned with the development of breathable (i.e.
comfortable) &fWWlXScoated fabrics for use in clean room
garments.
H. Future DevelqmentsThe development of improved protecti ve
clothing in theimmediate future will involve mainly the better
utilisation ofexisting types of textile material, and improved
garment design,rather than the development or invention of
radically new fabrics,materials, and garments. The steadily
increasing body ofknowledge on the properties of high Performance
fabrics andgarments in relation to the technical requirements of
protecti veclothing will certainly lead to an increased ability to
select andoptimise combinations of fabrics and garments to meet
specificand defined applications. At the heart of much of the
futuredevelopment work will be the need to provide
adequateprotection at an acceptable level of discomfort. The
generalpublic are becoming more aware of the .comfort aspects
ofclothing in general and there seems lit tle doubt that
thetolerante of garment .discomfort, especially perhaps in thearea
of work and protective clothing, is decreasing.lt is possible to
predict with some confidence, therefore, that inthe immediate to
middle future much effor t will be concentratedona) the development
of ways of eliminating garment discomfortin general and the
discomfort associated with liquid sweatin particular, and
1)2)3)4)
5)6)7)
8)9)
10)11)12)
Schoppee, M.M., Welsford, J.M., Abbott, N.J.; Proceedingof
ASTMSymposium on Performance of ProtectiveClothing, Raleigh, N.
Carolina p 340 (1984)Krasny, J.F; ibid p 463Young Moo Lee, Barker,
R.L.; Text. Res. J., Vol. 57, p 123(1!387)Baitinger, W.F.,
Konopasek, L.; Proceeding of ASTMSymposium on Perfor mance of
Protective ClothingRaleigh, N. Carolina p 421 (1984)Benisek, L.,
Phillips, W.A.; Text. Res. J., Vol. 51, p 191 (1981)Ulpublished
work at the British Textile Technology GroupVeghte, J.H.;
Proceedings of ASTM Symposium onPerformance of Protective Clothing,
Raleigh, N. Carolinap 487 (1984)Young Moo Lee, Barker, R.L.; J.
Fire Sei., Vol. 4, p 315(1!386)Gonzalez, R.R., Breckenridge, J.R.,
Levell, C.A., Kolka,M.A., Pandolf, K.B.; Proceedings of ASTM
Symposium onPerformance of Protective Clothing, Raleigh, N.
Carolinap 515 (1984)Wilson, N.; Inst. Phys. Conf. Series No. 66, p
21 (1983)Wilson, N.; J. Electrostatics , Vol. 16, p 231
(1985)Wilson, N.; Shirley Institute Bulletin, Vol. 55, p 8, p 44
(1982)
