Protective Clothing

Ing. Imtiaz Ahmed Khan Ph.D Scholar

KOD,FT, TUL

Introduction

 Clothing is a primary and fundamental need of mankind .

 Clothing gives a feeling of self confidence and comfort and the wearer feels physically, psychologically and socially at ease.

 Mainly used to cover and protect body.

Factors Affecting Clothing

Requirements

 Social Status and Economic Background

 Environment , Weather

 Age and Health conditions

 Occasion , Activity

 Faith and Ethnicity

Textiles Materials for Every Need

 Optimized moisture

management

 Better heat flow control  Improved thermal insulation  Breathability  High performance in hazard protection  Environmental friendly  Increased abrasion resistance

 Health control and healing aid

 Body control

 Easy care

 High aesthetic appeal

 Enhanced handle

 High/low visibility

Protective Clothing

 Nowadays safety and protective textile have become an integral part in one or other form. Safety and protective textile refer to garment and other fabric related items designed to protect the wearer from harsh environmental effects that may result in injury or death.

 Protective textiles are a part of technical textiles that are defined as comprising all those textile-based products which are used principally for their performance or functional characteristics rather than their aesthetic or decorative characteristics.

TWELVE SEGMENTS OF TECHNICAL TEXTILES

APPLICATION WISE

 AGROTECH (AGRICULTURE, HORTICULTURE AND FORESTRY)

 BUILDTECH (BUILDING AND CONSTRUCTION)

 CLOTHTECH (SHOES AND CLOTHING)

 GEOTECH (GEOTEXTILES, CIVIL ENGINEERING)

 HOMETECH (FURNITURE, UPHOLSTERY, INTERIOR

FURNISHING, HOUSEHOLD TEXTILES, FLOOR COVERING)

 INDUTECH (FILTERATION, CLEANING AND OTHER INDUSTRIAL USES)

 PROTECH (PERSON AND PROPERTY PROTECTION)

 MEDTECH (MEDICAL, HEALTHCARE AND HYGIENE)

 MOBILTECH (AUTOMOBILES, SHIPPING, RAILWAYS AND AEROSPACE)

 OEKOTECH (ENVIRONMENTAL PROTECTION)

 PACKTECH (PACKAGING)

 SPORTTECH (SPORT AND LEISURE)

Classification of Protective Clothing

 Classifying personal protective textiles or clothing is complicated because no single classification can clearly summarize all kinds of protection. Overlap of the definitions is common since there are so many occupations and applications that even the same class of protective clothing often has different requirements in technique and protection.

Further Classification

 Personal protective textiles can be further classified according to the end-use functions such as thermal

(cold) protection, flame protection, chemical

protection, mechanical impact protection, radiation protection, biological protection, electrical protection and wearer visibility.

Schematic Classification of Protective Textiles

Schematic flow chart of materials and technologies for manufacturing of Protective Textiles

Steps in selection of protective clothing materials Step 1: Assess hazards

Type of hazard(s)

Severity of the hazard

Step 2: Identify relevant standards, specifications or guidelines

 With well defined performance requirements

 Not well defined performance requirements

Steps in selection of protective clothing materials

Step 3 Screen materials based on protection performance of fabrics, e.g.

• Cold climate protection performance

• Chemical protection performance

• Biological protection performance

• Flame and thermal protection performance

• Mechanical protection performance

Step 4 Select materials based on other major factors

• Job performance

• Comfort

• Cost

• Durability

• Use, care & maintenance

We will

study

some aspects related to:

Heat & Flame protection clothing

Mechanical protection clothing

Extreme cold protection

 Chemical & Biological protection

 Radiation protection

 Electrical protection

High visibility Protection

(we will study today only highlighted topics)

Thermal Protective Clothing

Personal Protective Equipment

(PPE)

 Which includes personal protective clothing and gear such as respirators, face masks, and other controls,

forms a barrier between the person and the hazardous environment and prevents the wearer from injury and harm .

Firefighter’s Concerns

Firefighters are exposed to many hazards associated with their work environment such as:

 Toxic substances in the ambient air

 high radiant heat intensities

 hot flames

are common risks in fire extinguishing work.

Criteria that define heat and/or fire

performance

 Once heat is absorbed by a textile fiber, it may promote physical or chemical change or both. All organic fiber forming polymers will eventually thermally degrade at or above a threshold temperature often defined as the pyrolysis temperature, Tp.

 Level of damage to skin provides a relatively severe, yet survivable, performance criterion level for protective clothing.

Human Skin

 One of the primary objectives in the design of fire-fighting clothing is the prevention of thermal damage to the skin.

 To properly understand test methods for the

evaluation of fire-fighting clothing, one must have a sound understanding of the affects of thermal exposure on the skin.

 The skin is composed of three layers: the epidermis, dermis, and the hypodermis.

The Human Skin

Skin Damage

 Skin burns are evaluated by ranking the level to which the skin has been damaged. Several scales exist to evaluate skin burns and the most common is to rank by first, second, third degree or higher degrees.

Degree of burns (skin damage)

Superficial (First Degree)

 First degree burns are appropriately the most superficial. The thermal damage in this case only affects the epidermis. The physical signs of a first degree burns include redness and some pain

Partial Thickness (Second Degree)

 A second degree burn occurs when the epidermis is destroyed at the burn location. A superficial second degree burn does not damage the dermis. If the dermis is damaged, the trauma is considered a deep second degree burn. Physically, the skin will appear red, blistered, moist, and will be painful. A pale white color will appear under the blisters if the burn is deep.

Full Thickness (Third Degree)

 Third degree burns occur when both the epidermis and dermis suffer complete necrosis. This burn extends below the hair follicle depth. Damage may also penetrate the subcutaneous tissue. The skin is unable regenerate on its own, and will appear gray in color, charred, and have a leathery texture.

Fourth Degree and Beyond

 Although it is common to discuss first, second, and third degree burns exclusively, the rating system does extend to a sixth degree. Fourth degree burns are those which require skin grafts to heal the patient. Fifth degree burns are those in which the muscle is damaged. Sixth degree burns damage the bone.

Rate of Skin Damage

 The normal human skin temperature at the surface is

32.5oC, and thermal damage will begin when the temperature at the base of the epidermis, approximately 80-μm below the surface, is increased above 44oC.

 Damage to the skin is a function of the skin temperature,

and the period of time when this temperature is greater than 44oC. The rate of damage to the skin increases logarithmically, such that the rate of damage at 50oC is 100 times greater than the rate of damage at 45oC

 Regardless of the mode of application of the heat flux, the

temperature rise, and therefore the 2nd degree burn tolerance time, are related to the amount of heat absorbed by the skin.

· Routine conditions: Air temperature up to 50±60 ºC radiant heat flux up to1.4±1.6 kW/m2.

· Hazardous conditions: Air temperature from 50 ºC to 300 ºC radiant heat flux from 1.4 kW/m2 to 8 kW/m2.

· Emergency conditions: Air temperature from 300 ºC to 1000 ºC radiant heat flux from 8 kW/m2 to 200 kW/m2

Firefighters garments or Proximity

suit

 The term garment, when referring to firefighter turnout gear, is defined as the coat, trouser, or coverall elements of the protective ensemble designed to provide minimum protection to the upper and lower torso, arms, and legs, excluding the head, hands, and feet.

Proximity suit

 Fire proximity suit is a heat-reflecting metallic finished fabric, used in outer layer of fire-fighting applications.

 It is manufactured from vacuum-deposited aluminized material.

 It can be exposed in extreme heat such as aircraft fires and some chemical fires.

 Aluminised fire proximity suit are designed for rescue operations

and places at a temperature ranging 6000_F.

 The outer layer of these suit being aluminized helps to reflect about 90% heat.

1930’s 1937-43’s modern

suit:- The outer surface of the proximity suit is made by a mirror polished

aluminised finish.

Collar:- The collar is designed to be twice the height in the rear as in the

front.

Sleeves:- The sleeves of the coat are designed to act as zippered vent

opening in pit.

Front fastener:- The coat is opened and closed by both a backway zipper

covered by a Velcro closure.

There are three basic types of proximity suits:-

 Approach suit—used for work in the general area of high temperatures such as steel mills. (Ambient heat protection up to ~200 °F )

 Rescue suit—used for aircraft rescue and fire fighting (AR-FF) & for kiln work. (Kiln suit ambient protection upto 700 °F)

 Entry suit—used for entry into extreme heat and situations requiring protection from total flame engulfment. Most commonly made of ”Zetex” and not aluminized. Entry suit ambient protection ~700 °F for short duration and prolonged radiant heat up to 600 °F .

Material that used for proximity suits

 proximity suits are made-up of fire resistant fibres mainly aramids such as Nomex and Kevlar, Polybenzimidazol (PBI) fibres(<10

microns).

 Outer layer of flame-resistant fabric would not be destroyed easily through charring or melting .

 The fire retardency will last at-least few seconds in a flashover situation before catching the fire .

 Further, it is self –extinguishing.

3-layers of the garment

 Outer Shell: Advanced Nomex / Kevlar blend in a "Rip stop Weave", having

aluminised finish & also having puncture resistance.

 Thermal and Moisture barrier:- Thermal Layer (protects us from heat), and the

Moisture Barrier (keeps most moisture out), & usually made from PTFE film & TRIPROTECH membrane(Pores 0.01 to <1micron) containing 1.4 billion tiny holes per square centimeter. .

 Inner layer:- Thermal linear face cloth made up of wool.

This Laminated fabrics allows water vapour to diffuse through but prevent penetration of liquid water .

This suit weighs just 2.5 kg, and is 60% more effective in preventing second- and third-degree burns.

Thermal resistance & vapour permeability

 The objective of this is to decrease the potential for burns caused by heat transfer from flame to suit.

 Prevent the body from steam burns.

 moisture, present in fire-fighter turnout systems, has a complex influence on heat transmission and potential for skin burn injuries.

Wearable Technology Induction

Clothing is currently supposed to have more functions than just certain climatic protection and good look. These functions can be referred to wearing and durability properties.

A revolutionary new property of clothing is to exchange information. Clothing is now capable of recording, analyzing, storing, sending and displaying data, which is a new dimension if intelligent systems. Clothing can extend the user’s senses, augment the view of reality and provide useful information anytime and anywhere the user goes.

Application fields are:

• Working: displaying helpful data, connecting to the internet or to other people

• Medicine: monitoring health parameters • Security: detecting danger, calling for help

Implications for Research

 Protective textile materials benefit from the

development of a myriad of high-performance, thermal-stable fibers, and woven composites

 Protective clothing can greatly improve performance by adding smart/interactive features

 Smart thermal protective clothing:

 _{Detection of vital signals}

 _{Global Positioning System (GPS)}

 _{Wireless, hands-free communication}  _{Cooling – warming system}

 _{Incorporated warning signaling}

3-layer interlock woven structure

5-layer interlock woven structure

Multi-layered woven structures can increase thermal and fire protection by adding controlled air gaps. They can be tailored to provide other features such as an anti-static system, and physiological comfort

In a structured layered system, smart features may be added and supported by the matrix formed

air gaps

Detection of Vital Signals

Sensatex is developing a SmartShirt™ System specifically for the protection of public safety personnel, namely firefighters, police officers, and rescue teams. Used in conjunction with a wireless-enabled radio system, the SmartShirt™ can monitor the health and safety of public

safety personnel/victims trapped in a building or underneath rubble with the ability to detect the exact location of victims through positioning capability. In addition to monitoring vital signs, the system can detect the extent of falls, and the presence of hazardous gases; it also offers two-way voice communication

Global Positioning System (GPS)

Textiles integrated with sensory devices driven by a GPS can detect a user’s exact location anytime and in any weather.

Interactive electronic textiles with

integrated GPS enhance safety by quickly locating the wearer and allowing the suit to be heated. GPS can provide added

safety for firefighters and emergency personnel by facilitating offsite

monitoring of vitals

Thermal Imaging cameras

 Thermal imaging cameras can detect the slightest variations in thermal

energy

 The use of thermal imaging cameras may improve the ability of the

future fire fighter to navigate in a smoke-filled room to find potential victims.

Testing Techniques to Evaluate

Protective Clothing

 Ignition Resistance and Flammability

One method involves exposing the bottom edge of a vertical specimen to a flame for 12 sec (Method 5903, Flame Resistance of Cloth, Federal Test Method Standard 191). The NFPA Standard 1971, Protective Clothing for Structural Fire Fighting 1981, specifies that, in using this method, the length of the charred material must not exceed 100 mm and flaming must cease within 2 sec after the flame is removed.

LOI(Limiting Oxygen Index)

LOI

 A specimen is positioned vertically in a transparent

borosilicate glass test column and a mixture of oxygen and nitrogen is forced upwards through the column. The specimen is ignited at the top. If the flame remains for 3 minutes, or propagates down the length of the sample, the test is repeated at lower oxygen concentrations. If it self-extinguishes, the test is repeated at higher oxygen concentration. The oxygen concentration is adjusted in this manner until the specimen just supports combustion.

 materials with LOI 21% should still be considered

flammable.

Flash Fire Manikin test

 Large scale tests involve dressing a life size manikin with

fire fighter clothing and exposing the manikin to a fire environment. An entire ensemble can be tested rather than just a small piece of material.

 The manikin is composed of a thermally stable, flame

resistant, non-metallic material. It has 100 heat flux sensors which are located throughout the body (except the hands and feet). The heat flux sensors must be able to measure and withstand a heat flux from zero to 167 kW/m2, which is the maximum heat flux exposed to the manikin if not dressed in fire protective clothing(ASTM F 1930)

 the manikin in the test room specified in ASTM F 1930. The chamber is 7.0 feet by 7.0 feet by 8.0 feet and the manikin is located in the center to obtain a uniform heat flux across his body. The induced air combustion industrial style propane burners shown in the picture

 are located at the height of the manikin’s hips and knees in all four corners of the room produce a simulation of a flash fire. The fuel from these burners must provide a uniform heat flux of at least 84 kW/m2 over a minimum exposure time of five seconds

From this test, the total percentage of second and third degree burns are recorded.

Ballistic protection

Defence

textiles

History

 Pre Twentieth century

Normally heavy & uncomfortable uniform for wear. Produced from natural fibers or heavy metal is used. Uncomfortable for soldiers.

Twentieth Century

Light weight & durable, many high performance fibers came into usage.

Ballistic Protection

 With the introduction of bullets and bombs the protective garments for warfare has to be changed completely. To understand and appreciate the design of protective garment the designer must have some basic knowledge about bullets, guns and bombs.

Bullets: A modern cartage consists of:

1. The bullet itself, which serves as the projectile. 2. The case which holds all parts together.

3. The propellant for example gun powder.

4. The rim, part of the casing used for loading. 5. The primer, which ignites the propellant.

 Due to the smaller size of the bullet, the stress exerted on the bullet is large and cause severe damage. A bullet fired from a rifle or handgun has spiral spin that keeps it rotating and travel in straight way.

 The protective garment has to absorb or dissipate the force or load of bullet over a large area.



Bomb blast:

When the chemical reaction begins, the carbon decomposes to release gases. The gas initially expands at about 8050 meter/second. It applies a huge amount of force to everything in the surrounding area. The explosion has actually 2 phases. The initial expansion inflicts most of the damage. It also creates a very low pressure area around the explosion’s origin. The gases are moving outward so rapidly that they suck most of the gas out from the middle of the explosion. Explosive velocity is the velocity of the shock wave.

Effect of thermal pulse on clothing:

 Heat is generated and heat wave cause thermal pulse.

 Gas travelling at high temperature.

 Most severe is flying fragments.

 even only the air can cause severe damage

Materials Used

• Earlier silk & metal was used.

• But now high Performance fibres are used like

• _Kevlar - Polyphenylene terephthalamide, 5 times stronger

than steel. Properties like tensile strength at low weight, low elongation at break, high modulus

high chemical resistance etc.

• Dyneema – polyethylene, 10-100 times stronger than steel. Properties like very high strength to weight ratio & light enough to float on water.

• _{Twaron -} para-aramid, 5 times stronger than steel.

DURABILITY COMFORT

LIGHT WEIGHT

PHYSICAL REQUIREMENTS

PROPERTY

COMMENTS

Light weight and low bulk Items have to be carried by

individuals.

High durability and

dimensional stability

Must operate reliably in

adverse conditions

Good handle and drape

comfortable

Low noise and antistatic

No rustle and no sparks

ENVIRONMENTAL REQUIREMENTS

PROPERTY

COMMENTS

Water-repellent, water

proof & wind proof

For exterior materials

exposed to cold weather

Thermally insulating

For cold climates

Water vapour permeable

For clothing and personel

equipment

Rot-resistant

For tents, covers, nets

UV resistant light

Environment with sunlight

biodegradable

If discarded or buried

SPECIFIC BATTLE FIELD HAZARDS

TYPES

COMMENTS

Ballistic fragments

Bombs,grenades

Low & high velocity

bullets

Hand guns, pistols

Chemical & biological

agents

Blood agents, nerve agents,

bacteria

ECONOMIC CONSIDERATIONS

PROPERTY

COMMENTS

Easy care & min

maintainance

Non iron, smart

Long storage life &

minimal cost

War stock to be stored for

10-20 yrs

disposable

Nuclear & chemical

contamination

fragments _bullets

other 59%

19% 22%

Causes for ballistic

casualties in general war

Fabric layers in the armor

• Energy dissipation and reduction

Weave

• Plain balanced weave • More cross-over

points

• Large surface area .

Requirements

• Ballistic performance • Comfortable clothing

Ballistic resistance material Required degree of protection Final weight of uniform Comfort and ease

of movement Blunt trauma protection steel 1978 1992 materials of today 500 720 750 750 38 36 32 27

Ballistic material performance versus weight

ballistic limit (m/s) weight (oz/sq.ft)

c  Soft armour :-  20-30 layers stitched together.  Kevlar  Spectra  Hard armour :-  Multi-layered fabrics  Vinyl ester  Epoxy

no armor helmets are worn armor is worn armor and helmet is worn 80% 61% 40% 15%

Casualty levels

 Gearing towards an integrated future

 The general aims of future systems are:

 Improve protection against natural and battlefield threats

 Maintain thermo-physiological comfort or survival in extreme

conditions

 Improve compatibility between and within different clothing

components

 Reduce weight and bulk of materials

 Integrate functionality so that fewer layers provide multi layer protection

 Reduce life cycle costs by making systems more effective, durable,

and recyclable and by buying few components in the system