Chemical Protective Clothing

8/8/2019 Chemical Protective Clothing

1/47

TEXTILESTEXTILES

FORFORPROTECTIONPROTECTION

Keshav Dhawan

B.Tech(Textile Chemistry)-VII Sem

GNDU1


2/47

Contents

2


3/47

Introduction

Scientific advancements made in various fields have undoubtedly increasedthe quality and value of human life. It should however be recognized that

the technological developments have also exposed us to greater risks and

danger of being affected by unknown physical, chemical and biological

attacks. Fortunately, simple and effective means of protection from most of

these hazards are available. Textiles are an integral part of most protectiveequipment. Protective clothing refers to garments and other fabric-related

items designed to protect the wearer from harsh environmental effects that

may result in injuries or death.

3


4/47

Classification

4


5/47

Materials & Technologies

5


6/47

Steps In The Selection of Protective Clothing

Materials

6


7/47

Smart Textiles For Protection

Smart/interactive textiles (SIT) are materials and structures that sense and react to

environmental conditions or stimuli, such as those from mechanical, thermal, chemical,electrical, magnetic or other sources.

Smart Textiles can be divided into:Passive smart materials, which can only sense the environmental condition or stimuli.

Active smart materials, which sense and react to the condition or stimuli.

Very smart materials, which can sense, react and adapt themselves accordingly.

7


8/47

Contribution to Protection

Smart textiles can contribute to Protection and Safety in three ways:

They are able to detect conditions that signal increased danger.They prevent accidents by sending out a warning when hazardous conditions have been

detected.In the case of serious threats they can react by providing instantaneous protection.

Basically, five functions can be distinguished in a smart suit, namely:

Sensing.Data processing.Actuating.

Storage.Communication.

8


9/479

PolyeletrolyticGels

pH Sensitive Materials


10/47

CHEMICAL PROTECTIVE CLOTHING

FOR

INDUSRIAL WORKERS

10


11/47

Chemical ProtectionProtective clothing cannot be made generic for all chemical applications, since chemicals vary

in most cases and a particular CPC can protect only against a limited number of specificchemicals.

Important considerations in designing chemical protective clothing are :

The amount of chemical permeation.

Breakthrough time for penetration.

Liquid repellency.Physical properties of the CPC in specific chemical conditions.

Chemical protective clothing can be categorized as encapsulating or non-encapsulating based

on the style of wearing the clothing.

CPC is rated for four levels of protection, levels A, B, C and D from highest protection tonormal protection

11


12/47

Routes of ExposureInhalation Oral Dermal

NoseLungs

Mouth

Stomach

EyesSkin

12


13/47

Classification

13


14/47

Cont..

14


15/47

Requirements

Chemical Protective Clothing Should Resist : Permeation , Degradation, Penetration.

Durability

Flexibility

Temperature Resistance

Service Life

Clean Ability

15


16/47

Permeation

Permeation is the diffusion of a chemical on a molecular basis through

chemical protective clothing. This movement of the chemical through the protective material may not be

readily noticeable because it occurs on a molecular or microscopic level. The time it takes the chemical to pass through the protective material until it

is first detected by an analytical instrument is called the breakthrough time.

16


17/47

Degradation

The change in the physical properties of the material as a result of adverse

effects of the chemical is called degradation.Physical properties may include material weight, dimensions, tensile strength,

hardness. The most common observations of material degradation are Swelling,

Discoloration , Loss of Strength or Deterioration.

17


18/47

Penetration

Penetration is defined as `the flow of chemical through closures, porous

materials, seams, and pinholes and other imperfection in a protective clothing

material on a non-molecular level.This definition is intended to accommodate both liquids and gases. Penetration of chemicals may take place through Zippers, Seams or

Imperfections in Protective Clothing.

18


19/47

Materials For CPC

19


20/47

Textile MaterialsOrdinary textile materials are generally not considered suitable for protection against

chemicals, however special non-coated textile materials are used for a variety of applicationsinvolving particulates and light liquid spray from relatively non-hazardous chemicals.

Though woven textiles are not often found in chemical protective clothing, very tightly woven,

repellent-treated fabrics can provide some very low minimum protection against liquid exposure.

More common are nonwoven fabrics that have demonstrated barrier performance againstparticles and repellency of liquids.

Two predominant examples of nonwoven fabrics are flashspun polyethylene (Tyvek) and

spunbond/ meltbown/ spunbond (SMS) polypropylene (Kleenguard).

These textiles are used because of their relatively low cost and because the materials provide astructure of microfibers that filter out dry particulates and many water-based liquids.

20


21/47

Flash Spun PolyethyleneMade from very fine, high-density polyethylene fibers, lightweight yet strong; vapor-

permeable, yet water- and chemical-resistant, as well as puncture-, tear- and abrasion-resistant.

Tyvek is formed by a fully integrated process using continuous and very fine fibers of 100%

high-density polyethylene that are randomly distributed and no directional. These fibers are first

flash-spun, then laid as a web on a moving bed before being bonded together by heat and

pressure - without the use of binders.

Extensive Temperature Range, Excellent Dimensional Stability: -73C (132C).

21


22/47

SMS PolypropyleneBreathable fabric multilayered laminate.

The two outer spun bond layers are made of randomly deposited 15 20 micron

diameter continuous polypropylene fibres which provide cloth-like comfort while also

offering fabric strength, durability and abrasion resistance.

The inner melt blown layer provides a filter barrier and is typically comprised of 1-3

micron diameter polypropylene fibres.

The advantage of melt blown as the barrier layer is that it is permeable to both air

and moisture vapour, meaning that both air and sweat vapour can pass through the

garment to keep the skin cool and the wearer more comfortable in hot working

environments.

22


23/47

4 Advantages of SMS

Provides strength and durability to the garment

Excellent barrier to chemicals and particlesNon-fibrous ultra low lint

Anti-static to EN1149-1Non-woven

Film

The melt blown barrier layer provides a great deal of particulate and liquid protection.

Bonded together, these layers result in a tough cloth-like fabric that provides a high degree

of protection and comfort. 23


24/47

Unsupported Rubber and Plastic Materials

Normally, chemical protective clothing materials include supporting textile fabrics to

provide strength.

However, there are some CPC materials that do not include a fabric substrate. The

rubber material or plastic is thick enough to provide sufficient strength for clothing use.

Examples of polymers used in these materials are polyvinyl chloride and chlorinatedpolyethylene.

Because the materials are continuous, they offer a barrier to liquids and can be used

in the construction of CPC intended for protection against liquids and gases.

24


25/47

Micro Porous Film-Based Materials

Microporous films have millions of microscopic pores per square inch of the film

structure.In most cases, the pores are irregularly shaped with tortuous paths through the film.This material feature makes the film `breathable' .The microporous films are generally glued or laminated to woven or nonwoven

fabrics for physical support.

Owing to their physical structure, these fabrics provide barrier performance againstliquids but not gases.

25


26/47

Adsorbent-Based Materials

These materials include adsorbents, such as activated charcoal or other sorbent

materials.Activated Carbon :Activated carbon in very fine powder or granular form is usefulto purify both water and air. Activated carbon has particular affinity to organic

materials such as solvents used in printing inks and common coatings.

(a) Granular (b) Fibrous

26


27/47

Cont..

Development of Chemical Protective Clothing:

The chemical protective clothing is formed by five layers, the outer shell made ofpolyester as it has low absorption of 2% and it provides a good strength to the fabric

and polyester has a good resistance to lab grade chemicals. The inner layer is made up

of cotton fabric as it gives good absorbency and comfort. The middle layer comprises

of cotton non woven sandwiched with activated carbon.

The polyester fabric has 2% absorption, to avoid penetration of liquid chemicals

through the fabric; the fabric is finished with water repellent chemical NUVA HPU

27


28/47

Water Repellent Finishing of PET

Nuva HPU

1. Appearance - Liquid, milky-white dispersion

2. Chemical character - Dispersion of a flour compound

3. Ionic character - slightly cationic

4. pH - about 4 (5% as supplied aqueous)

Recipe:

Nuva HPU : 50 gpl

Acetic acid : 0.5 1.5 ml/l

Procedure:

28

TECHNIQUE OF EMBEDING ACTIVATED


29/47

TECHNIQUE OF EMBEDING ACTIVATED

CARBONThe carbon used had the following specifications :

Carbon Tetra Chloride Adsorption % 75-85Apparent Density gm/cc 0.42 - 0.47

Ash Content (Max) % max 2.5

Ball - Pan Hardness Number 96.5+

pH 9-11

Surface Area sq. M/gm 1300 1400

Size of granules 0.85 X 0.300 mm

The conventional chemical protective clothing was based on embedding activated carbon using

adhesives and polyurethane foam with a activated carbon load of 120 160 GSM.

These fabrics had low comfort properties of air permeability and thermal comfort causingstress to the wearer.

29

N dl P hi T h l


30/47

Needle Punching Technology

The novel technique of embedding activated carbon uses a base fabric made of 100 % cotton and

needle punched cotton non-woven.

The activated carbon granules coated over the double pass needle punched fabric gets embedded

in the non-woven. The cotton fibers dose not allows the carbon granules to move from its place.The activated carbon coated non woven had a GSM of 341. 30

C t N dli


31/47

Cont.. Needling

The fabric thus prepared was fed in to the needle punching machine through a pair of

conveyors and calendar rollers.To provide a initial cohesion to the layers a pressure of 6 bar was maintained at front and back

pair of calendar rollers.The web was fed such that the cotton woven fabric as the top layer.

The fabric layers were needle punched with following settings:

In feed speed 0.4 m /min

Draw off speed : 0.4 m/ min

Strokes / min : 152

Depth : 15 mm

Width : 700 mm

31

B di f N W & PET F b i


32/47

Bonding of Non-Woven & PET Fabric

The activated carbon sandwiched non woven and polyester fabric are bonded

together using acrylic resin.Acrylic resin provides a good strength along with flexibility.The fabric is placed on a platform and the resin is uniformly sprayed on the

fabric using a hand spray gun . The cotton non woven is placed over the fabric and the fabric is applied with

uniform pressure. Thus prepared fabric is cured at 110 0C for 2 min.

The maximum penetration was in case of acetone and it was 0.4 %,

while the no penetration in case of hydrogen peroxide and sodium

hydroxide.The maximum permeation was in case of dichloromethane and it was

10.79%, while no permeation in case of sulphuric acid.

The maximum degradation was in case of sulphuric acid and theweight loss of the fabric was 18.60%, while no degradation in case of

sodium hydroxide, Hydrochloric acid and Dimethyl Formamide.

32

M t i l F CPC C t


33/47

Material For CPC .Cont

Coated fabrics:Materials using this construction tend to be heavy, but relatively rugged and are used in a variety

of chemical protective clothing. Today, the most common clothing using coated fabrics are

splash suits, but some higher-end totally encapsulating suits may be made from coated fabrics.

Plastic laminates :These materials combine various plastic polymer films with nonwoven substrate fabrics resulting

in chemical-resistant, lightweight, relatively inexpensive materials. The majority of substrates arebased on polypropylene and films are based on polyethylene and polyvinyl alcohol polymers, but

more sophisticated films may employ a variety of different plastic films in a single laminate.

Combination or specialized materials:These fabrics generally attempt to combine the best attributes of each class. For example, coated

fabrics have been laminated with a plastic film on one side to provide the flexible featuresassociated with rubber-based fabrics and the high levels of chemical resistance. Microporous

films can be combined with adsorbent-based materials to provide a film with liquid chemical

resistance that adsorbs large molecular weight chemical vapors.

33

G t D i F t


34/47

Garment Design Features

The type and location of Seams.

The type, length, and location of the closure system(s).

The type and characteristics of visors or face shields, if integrated into garments.

The design of interface areas with other chemical protective clothing or equipment.

34

S


35/47

Seams

35

Cl S t


36/47

Closure Systems

Closures are typically the `weak' link in the chemical protective clothing barrier.

The simplest closures are zippers or a series of snaps.CPC designs use storm flaps to cover the zipper or snaps.

Liquid-repellent zippers are conventional zippers that use rubber or plastic coated tape instead

of woven cloth on the sides of the zipper and that have a special chain (teeth) that are coated to

limit liquid penetration.

Two-track closures involve two extruded pieces of plastic that fit together to provide a seal much

like many plastic sandwich bags. These closures offer good integrity against liquids (and vapors)

but can be difficult to seal over a long length .

The pressure-sealing zipperuses a compressible rubber or plastic material with a zipper chain

to push the two sides of the closure material together for creating a seal. These zippers tend to be

bulky and expensive but are generally required when total encapsulation of the wearer is

required.

36

G t Vi


37/47

Garment Visors

Visors are generally incorporated into suits to offer chemical barrier protection for the head and

face area. In general, the visor is constructed from a material that provides clear undistorted

vision as well as chemical resistance.

The principal materials used in visor construction are polyvinyl chloride, polycarbonate, and

polymethacrylate.Since the visor material must provide optical qualities, only transparent materials can be

chosen as visors.

When greater chemical resistance is required, the visor made be made of a composite material

that includes fluorinated ethylene propylene (FEP) laminated to PVC.

37

I t f A


38/47

Interface Areas

Principal CPC Interfaces include:Amount of overlap for multi-piece garments.

Upper torso garment sleeve to glove.Lower torso pant cuff to footwear.Upper torso garment collar to hood.Hood to respirator.

If different pieces of chemical protective clothing are worn, the items should provide sufficient

overlap to cover the wearer's skin particularly during bending over.

Elasticized sleeve ends provide somewhat better conformance of the sleeve with the glove.A straight cuff is used. The cuff is generally pulled over the boot to keep liquid from entering

the top of the boot or footwear.

38

L l f Ch i l P t ti


39/47

Levels of Chemical Protection

In Hazardous Material operations there are four levels of protection.

Level A

Level B

Level C

Level D

39

L l A


40/47

Level A

Fully encapsulating suit with self-contained breathing apparatus.

Level A should be worn when the highest level of respiratory, skin, and eye

protection is required.

Level A is used when:

Conditions are unknown.

The hazardous substance has been identified and requires the highest level

of protection for skin, eyes, and respiratory system.Operations are being conducted in confined, poorly ventilated areas.

Work function involves a high potential for splash, immersion, or

exposure to unexpected skin hazards .

40

Le el B


41/47

Level B

Self-contained breathing apparatus, Chemical protective clothing,

gloves, and hard hat.

Should be selected when the highest level of respiratory protected is

needed and some degree of skin protection is required. Level B is

the minimum recommendation for initial site entry.

Level B protection is used when:

Air contaminants are unknown.

Air contaminants have been identified and the criteria for using

APRs are not met.

The atmosphere contains less than 19.5% oxygen.

Direct contact does not pose a severe skin hazard.

41

Level C


42/47

Level C

Air-purifying respirator, chemical protective clothing, gloves, boots, and

hard hat.

Level C should be selected when types of airborne contaminants

are known, the concentrations are measured and the criteria for

using air-purifying respirators (APRs) are met.

Level C protection is used when:

Criteria for the use of APRs are met.

Air contaminants have been identified and concentrations

measured.

Direct contact does not pose a skin hazard.

42

Level D


43/47

Level D

Chemical-protective clothing, boots, gloves, and hard hat.

Level D should not be worn on any site with respiratory or skin hazards.

Level D is primarily a work uniform providing minimal protection.

Level D protection is worn when:

Atmosphere contains no known hazards.

Work functions precludes the potential for unexpected exposure

to hazardous levels of any substances.

43

Ulti t P d t


44/47

Ultimate Product

44


45/47

Various Test Method For CPC

ASTM F1186-03

ASTM F1001-99aASTM F739-99aASTM F1383-99aASTM F1407-99a

ASTM F1194-99ASTM F903-03ASTM F2053-00

ASTM F2130-01

EN 943-1:2002EN 467:1995EN374-3:1994EN ISO 6529

ISO 6530 (1990)ISO 13994 (1998)ISO 17491(2002)

45


46/47

Further Reading

Textiles for protection Edited byRichard A. Scott Woodhead, Cambridge.Military textiles Edited by Eugene Wilusz Woodhead, Cambridge.Intelligent Textiles for Personal Protection and Safety Edited by Sundaresan Jayaraman Georgia

Institute of Technology, USA Paul Kiekens Ghent University, Belgium and Ana Marija Grancaric

University of Zagreb.Stull J O, `Selecting chemical protective clothing,' Occup Health & Safety, December 1995, 2024.Abbott N J (2001), `Coated fabrics for protective clothing', in Satas D and Tracton A A., Coatings

technology handbook (2nd edn), Marcel Dekker, 819823.

Hall M E (2000a), `Finishing of technical textiles', in Horrocks A R and Anand S C, Handbook of

technical textiles, Woodhead, Cambridge.Mona Suri, D Rastogi, K.Khanna, Development of protective clothing for pesticide industry: part

I, Indian Journal of Fibre & Textile Research, vol.27, pp. 85-90, march, 2002. www. Scribd.com http://www.kcprofessional.com/us/kcp-brands/kleenguard/kleenguard.asp

http://www.lakeland.com

46


47/47

Be pro-active not reactive towards safetyBe pro-active not reactive towards safety

Chemical Protective Clothing

Documents

Transcript of Chemical Protective Clothing