protective clothing.pdf
TRANSCRIPT
-
7/27/2019 Protective Clothing.pdf
1/25
Dr. V. K. Kothari
Department of Textile Technology, IIT, Delhi
Schematic of classifications of Protective Textiles
-
7/27/2019 Protective Clothing.pdf
2/25
Flame retardanto Kermel and Kermel / Viscose fabrics for
flight suits, station wear and turnout gear.o Nomex for military applications
o Molten Aluminum splash protective fabric.
o Electrical Arc
Ballistic protectiono p Aramid woven fabric for hard and soft
ballistic applications
Lint free antistatico Continuous filament polyester / carbon fabrics
Medical textileso Systemic and non systemic antibacterial and
antistatic fabrics for surgeons gowns, scrubs and
warm up jackets.
Chemical protectiono Liquid chemical protective fabrics
UV protectiono Fabrics that offer a UPF rating for the wearer.
Industrial work wearo Component fabrics for chain saw protection
o freezer suits
o waterproof clothing
Military textileso Uniforms
o Parachutes
-
7/27/2019 Protective Clothing.pdf
3/25
Materials & Technologies
Processing technologies for specific
protective clothing are different, the main
processes generally include:
Material manufacturing or selection;
Producing fabrics and other related items;
Finishing, and
Clothing engineering.
-
7/27/2019 Protective Clothing.pdf
4/25
Schematic of materials and technologies for
manufacturing 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
-
7/27/2019 Protective Clothing.pdf
5/25
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 majorfactors
Job performance
Comfort Cost
Durability
Use, care & maintenance
AGENDA
Look at some aspects related to:
Extreme old protection
Chemical & Biological protection
Radiation protection
Electrical protection
Heat & Flame protection
Mechanical protection High visibility Protection
-
7/27/2019 Protective Clothing.pdf
6/25
EXTREME COLD PROTECTIVE CLOTHING
Hazards of Extreme Cold Climate
Increased incidence of Arthritis,Rheumatism and Bronchitis
Cold metal injury
Hypothermia - one of the serious
hazards of cold exposure Frostbite
-
7/27/2019 Protective Clothing.pdf
7/25
Comfort & Survival Factors in
Cold Protective Clothing
1. Physiological Factors
Metabolic heat output
Perspiration rate
2. Environmental Factors
Wind Chill
Relative Humidity or Dampness of theEnvironment
3. Fabric Factors
Thermal insulation
Air permeability
Moisture vapour permeability
4. Design of the Fabric Assembly
-
7/27/2019 Protective Clothing.pdf
8/25
The human heat balance equation
Appropriate protection against cold is provided when the human body is in heat
balance at acceptable levels of body temperatures (for example skin and core
temperatures).
This implies that heat losses are equal to metabolic heat production.
The following equation describes the heat balance.
where S is the rate of change in body heat content,
M is the metabolic heat production,
C is the convective heat exchange,
R is the radiative heat exchange,E is the evaporative heat exchange,
and RES is the respirative/airway heat loss, all in W/m2.
Thermal insulation
Evaporative resistance
Wind resistance
Water resistance
Measurements of clothing performance
-
7/27/2019 Protective Clothing.pdf
9/25
Category of Fibres which provides
Thermal Insulation
A. Heat Insulating
- to entrap as much air as possible.
- Low compressibility and high resilience
- Conventional fibres, hollow fibres & highbulk fibres
B. Heat Absorbing
- to maintain the microclimate inside theclothing
- Solar radiation absorbing fibre and fibrescontaining ceramic particles to absorb IRradiation
C. Heat Storing- Phase change materials
-
7/27/2019 Protective Clothing.pdf
10/25
Types of Layer- Combination
Outer layer should provide adequateresistance to wind penetration & shouldbe water vapour permeable
Next-to-skin layer of the garment shouldwick the liquid sweat away from thebody rapidly
Middle layer(s) should provide the maininsulation. Body heat should be
reflected back using a inner reflectivelayer.
-
7/27/2019 Protective Clothing.pdf
11/25
-
7/27/2019 Protective Clothing.pdf
12/25
Structural Model of a Cold Weather
Protective Clothing
Laminates with Aluminum Film
-
7/27/2019 Protective Clothing.pdf
13/25
Engineered Fibres
An unique polyester fibre such as Primaloft Air pockets increases the thermal resistance and
help it to resist the passage of water whileallowing body moisture in form of water vapour toescape
Insulation through Incorporation of
Integrated Heating Panels
Light weight, washable heating panelspowered by batteries are laminated inthe fabric
-
7/27/2019 Protective Clothing.pdf
14/25
Smart Polymeric Membranes
Laminated fabrics made frommonolithic breathable membranewhich react to build up of heat andmoisture
As the microclimate temperaturerises, the openings between thepolymer molecules in the membrane
expand, thereby increasing the fabricmoisture permeability. As thetemperature drops the pores in the
Chemical Protection
Chemical Hazard
Affects human based on its characteristics and mode of entry
Chemicals present a variety of hazards such as toxicity,
corrosiveness, flammability, reactivity, and oxygen deficiency
Routes of chemical entry into the human body are oral,
respiratory, and dermal
Dermal exposure considered primary mechanism of chemical
entry through human body
-
7/27/2019 Protective Clothing.pdf
15/25
Chemical Resistant Clothing
It provides an effective barrier between thechemicals used & area of the body to be protected
No single material will protect against all chemicals
Appropriate chemical resistant clothing must demonstrate:
No penetration
No significant degradation
Low permeation rate
-
7/27/2019 Protective Clothing.pdf
16/25
Chemical/Biological (CB) warfare agents and their effects
To design and to fabricate effective CB protective clothing, it is necessary to
have an understanding of the hazardous threats that must be prevented from
reaching the wearer.
CWAs are defined as natural or synthesized chemical substances, whether
gaseous, liquid or solid, which might be employed because of their direct toxic
effects on man, animals and plants.
BWAs are microorganisms (viruses and bacteria) or toxins derived from
living organisms.
They are used to produce death, or incapacitation in humans, animals, or
plants. Typical effects of selected CWAs are listed in Table given in the
next slide.
Chemical and biological protection
Typical effects of toxic chemicals, microorganisms, and toxins
-
7/27/2019 Protective Clothing.pdf
17/25
There are basically four different types of CB Protective Materials.
Figure illustrates the differences in their protective capabilities.
Different types of protective materials
Examples of Chemical Protective Cloth ing
z Three layers outer fabric, sorptive layer and inner layer
Layers of Protective Clothing
Outer shell is water repellent layer protecting from liquid chemicals Sorptive layer is soul of protective clothing absorbing liquid &
air borne chemicals
Inner layer provides comfort to the wearer
-
7/27/2019 Protective Clothing.pdf
18/25
Development of Chemical Protective Clothing
Polyester fabric
Cotton Nonwoven
Activated carbon
Cotton Nonwoven
Cotton fabric
Formed by five layers
Outer shell made of polyester as it has low absorption of 2% &
provides good strength to the fabric and polyester has a good
resistance to lab grade chemicals
Inner layer is made up of cotton fabric as it gives good
absorbency and comfort
Middle layer comprises of activated carbon sandwiched in
cotton nonwoven
Chemical Protective Clothing
-
7/27/2019 Protective Clothing.pdf
19/25
CPC Garment materials
Textiles
Unsupported rubber or plastics
Microporous film basics
Adsorbent-based fabrics
Coated fabrics
Plastic laminates
Combinations
The use of excellent protective materials, effective closures, and
ergonomic survival equipment for an individual will be meaningless
and unproductive without proper garment designs.
There are different garment designs given as follows:
Coverall or one-piece garments
Two-piece garments
Undergarments
Multilayered garments
Closure system, components, and systems
Clothing system designs
-
7/27/2019 Protective Clothing.pdf
20/25
UV exposure and human skin
Effect of UV rays on different types of skin
Radiation Protection
Ultraviolet radiation band
UVA(320 to 400 nm)
UVB(290 to 320 nm)
UVC(200 to 290 nm)
Causes little visiblereaction on skin
but decreaseimmunologicalresponse of skin cells
Responsible for
development ofskin cancers
Totally absorbed by
atmosphere &doesnt reach theearth
Radiation Protection
-
7/27/2019 Protective Clothing.pdf
21/25
Fabric's ability to block UVR dependent on several parameters:
Principal Parameters
Fiber Chemistry Fabric Construction Moisture content Wet Processing History
WeightThicknessPorosity
Dye
Concentration
Fluorescent
Whitening
Agents
UV-absorbers
Textiles as protection from ultraviolet radiation
Schematic representation of a textile as a barrier to UV radiation
-
7/27/2019 Protective Clothing.pdf
22/25
Electrostatic Protection
The term `electrostatic' or `static electricity' refers tothe phenomenon associated with the build up of
electrical charges generated, for example, by contact
and/or rubbing of two objects. Static electricity is
generated by unbalancing the molecular configuration
of relatively non-conductive materials.
Discharge of static electricity
In principle, there are three methods for
neutralizing charges on insulators:
conductance through the bulk of the material
conductance along the surface of the material
the attraction of oppositely charged ions from
the air
-
7/27/2019 Protective Clothing.pdf
23/25
Measurement techniques
There have been two main approaches to assessing theelectrostatic propensity of textile materials.
One is to measure the charge built up on a clothed
person or the electrical capacitance of a body (human-
body model)
The second is to measure some electrostatic
characteristics of textiles (e.g., surface resistivity,
charge decay rate, peak potential, etc.) in small-scaletests.
The most common way to confer anti-static properties on a fabric is to
incorporate conductive fibres/yarns.
Common conductive elements used in
fabrics include carbon, copper, silver,
stainless steel or metallic salts.
The choice of conductive product will
partly depend on the end use and the
required level of static protection.
-
7/27/2019 Protective Clothing.pdf
24/25
Modern ESD-textiles
Many ESD-garments are made of heterogenouscomposite fabrics where a grid or stripes of
conduct ive threads are present inside an
insulating matrix of cotton, polyester or mixtures
of these materials.
The conduct ive threads are more and morefrequently made by composites, i.e. by a mixture
of conductive and insulating fibres.
There are several variations in both fabric andthread s tructures.
-
7/27/2019 Protective Clothing.pdf
25/25
Gore-tex: Antistatic
Source: AVANTEX 2000