Protection and Safety

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Protection and Safety

• Chapter 14
• Safety Aspects and Protective Properties of
  Textiles
• (Collier Epps, 1999)

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All textiles are protective to some extent ?!?!
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What is, then, the main difference between common
textiles and PROTECTIVE TEXTILE MATERIALS?
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Protection/Safety Properties

• Protection/Safety properties of textile materials
  are those that protect the human body from a
  variety of hazardous environments and harmful
  substances

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What is HAZARD?
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A hazard is any source (event, conditions,
substance) of potential damage, harm or adverse
health effects on something or someone under
certain circumstances.
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Basically, a hazard can cause harm or adverse
effects (to individuals as health effects or to
organizations as property or equipment losses).
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Sometimes a hazard is referred to as being the
actual harm or the health effect it caused rather
than the hazard. For example, the disease
tuberculosis (TB) might be called a hazard by
some but in general the TB-causing bacteria would
be considered the "hazard" or "hazardous
biological agent".
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What is RISK?
Risk is the chance or probability that a person
will be harmed or experience an adverse health
effect if exposed to a hazard. It may also apply
to situations with property or equipment loss.
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Protection/Safety Properties

• Hazardous Environments
• Chemical
• Thermal (heat, fire, molten metal, and electric
  arc)
• Mechanical (impact and cut/slash/puncture)
• Radiation (nuclear, UV and electromagnetic)
• Biological
• Extreme ambient conditions

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Protective Clothing

• Personal Protective Clothing is designed to
  extend peoples physical and physiological
  limitations in response to environmental and
  hazardous conditions.
• Selection Criteria
• Protection and safety
• Comfort and functional fit
• Durability
• Functional design details
• Appearance
• Maintenance
• Cost

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Protection From Thermal Hazards

• The primary function of thermal protective
  clothing is to minimize or eliminate physical
  harm as a result of fire or exposure to hot
  surfaces, molten metal splashes, electric arc
  explosions, etc.
• The performance of thermal protective clothing
  depends on its ability to insulate and to
  maintain structural integrity when exposed to
  high heat.

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• Materials for Thermal Protection
• Inherent thermal-stable fibers
• Aramid (Nomex, Kevlar, Kermel)
• Polybenzimidazole (PBI)
• Carbon
• Novoloid
• Sulfar
• Polyphenylene sulfide (PPS)
• Fire-retardant (FR) finished fibers
• Cotton
• Wool
• Rayon
• polyester

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• Factors Affecting Fire/Heat Protection
• Burning behavior (thermal resistance)
• Fabric structure
• Thermal inertia (TI)
• TI density x heat capacity x thermal
  conductivity
• Guidelines to Ensure Maximum Effectiveness
• Anything worn over protective clothing should be
  made of FR material, specially the outermost
  garment or layer
• Avoid undergarments such as nylon or
  polyester/cotton blends that can melt against the
  skin and increase the severity of burn injury
• Wear controlled loose-fitting clothing to
  increase the insulating effect of air between
  clothing layers

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• Methods of Testing Heat/Fire Protection
• Ignition Resistance and Flammability
• Resistance of textile materials to burn
• Tendency of textile materials to burn
• Flame spread properties
• Ease of ignition
• Limiting Oxygen Index
• Heat Protective Properties
• Thermal Protective Performance (TPP) or Exposure
  Energy to Thermal End Point is the thermal energy
  input to a fabric specimen that is required to
  result in a heat transfer through the specimen
  sufficient to cause a second-degree burn in human
  tissue

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Protection From Chemical Hazards

• Workers need to be protected from a wide range of
  hazardous chemical substances, such as
  pesticides, in the form of solid, liquids, or
  gases.
• Effectiveness as barrier against a specific
  chemical, the style and construction, comfort
  factor, mode of use, and cost have an impact on
  the selection of CPC.
• Polymer materials used in CPC
• Tyvek
• Saranex (Saran-laminated Tyvek)
• Teflon

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• Permeation Testing
• Permeation of a liquid or vapor through
  protective clothing material, involves three
  steps
• The sorption of the chemical at the outside
  surface of the CPC material
• The diffusion of the chemical through the CPC
  material
• The desorption of the chemical from the inside
  surface of the CPC

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• Factors Affecting Permeation Assessment
• Temperature
• Material Thickness
• Solubility Parameter
• Multi-component Liquids
• Persistent Permeation
• Design and Construction of Protective Clothing
• Performance Standards for CPC
• NFPA 1991, Standard on vapor protective suits for
  hazardous chemical emergencies
• NFPA 1992, Standard on liquid splash protective
  suits for hazardous chemical emergencies
• NFPA 1993, Standard on protective suits for
  non-emergency, non-flammable hazardous chemical
  operations

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Protection From Mechanical Hazards

• Impact Protection
• Impact is defined as a violent contact or
  collision. During the impact event, three actions
  result from the application of forces on impact
• Tension
• Shear
• Compression
• In order to design protective body coverings, it
  is important to understand the factors in impact
  on the human body that may lead to injury.
  Critical conditions for body protection
• Pressure
• Gradual deceleration
• Momentum
• Elasticity

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• The most basic objective of impact protective
  equipment is that prevents penetration of the
  body by an impacting object.
• Age, gender, build up, general health, and
  physical and psychological condition on an
  individual affect body tolerance to a specific
  injury.
• Material for Impact Protection
• Elastic solid foams
• Fiber-reinforced resins
• High-performance polyethylene
• Para-aramid (Kevlar)
• Light-weight metals
• Ceramics

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• Factors Affecting Impact Protection
• Material content
• Fabric structure
• Tensile, shear and compression strength
• Resistance to extreme temperatures
• Fabric stiffness
• Testing Impact Protection
• Ballistic tests (V50 ballistic limit)
• ASTM Guide F2053-00 Standard Guide for
  Documenting the Results of Airborne Particle
  Penetration Testing of Protective Clothing
  Materials.

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• Cut/Slash/Puncture Protection
• Protection against mechanical aggressors is based
  on the same principles as protection from larger
  scale impacts.
• Materials that protect from cut, slash or
  puncture either have a strong, solid surface that
  repels the aggressor (sending its kinetic energy
  off in another direction) or are composed in a
  way that allows some sort of energy exchange to
  take place.
• Materials used solely for cut resistance do not
  have to provide impact protection but need to
  resist cutting

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• Materials Used for Cut/Slash/Puncture Protection
• Cotton
• Leather
• Nylon
• Polyester
• Carbon fiber
• High-performance polyethylene
• Para-aramid (Kevlar)
• Common Protecting Products
• Cut-resistant gloves
• Protective sweaters
• Medical glove liners
• Chain saw cut protection

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• Testing Cut/Slash/Puncture Protection (ASTM)
• F1342-91(1996)e2 Standard Test Method for
  Protective Clothing Material Resistance to
  Puncture
• F1414-99 Standard Test Method for Measurement of
  Cut Resistance to Chain Saw in Lower Body (Legs)
  Protective Clothing
• F1458-98 Standard Test Method for Measurement of
  Cut Resistance to Chain Saw of Foot Protective
  Devices
• F1790-97 Standard Test Method for Measuring Cut
  Resistance of Materials Used in Protective
  Clothing
• F1818-97 Standard Specification for Foot
  Protection for Chain Saw Users
• F1897-98 Standard Specification for Leg
  Protection for Chain Saw Users

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Cut Protection Performance Tester
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Protection From Biological Hazards

• Biological hazards involve living organisms that
  can reproduce in supportive environments. They
  are particular dangerous because small amounts
  can contaminate a community once they have
  entered just one host and subsequently been
  passed to others while they continue to grow.
• Biological hazardous substances may reach and
  eventually harm the body by four different
  routes
• Direct contact
• Breathing in
• Ingestion
• Injection

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• Materials for Biological Protection
• Physical Methods of Imparting Protection
• Three-layered composite non-wovens (spun-bonded/
  melt blown/spun-bonded)made of polypropylene or
  polyester/pulp.
• Polyethylene-coated wet-laid non-wovens
• Melt blown microfiber filter media for masks
• Chemical Methods of Imparting Protection
• Antimicrobial-coated woven and non-woven
  materials
• Liquid-repellent fabrics and membranes

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Mechanical Pressure Tester1
1 ASTM F23.40.04, Draft test method for the
resistance of materials used in protective
clothing to penetration by synthetic blood.
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• Testing Biological Protection (ASTM)
• F1670-98 Standard Test Method for Resistance of
  Materials Used in Protective Clothing to
  Penetration by Synthetic Blood
• F1671-97b Standard Test Method for Resistance of
  Materials Used in Protective Clothing to
  Penetration by Blood-Borne Pathogens Using
  Phi-X174 Bacteriophage Penetration as a Test
  System
• F1819-98 Standard Test Method for Resistance of
  Materials Used in Protective Clothing to
  Penetration by Synthetic Blood Using a Mechanical
  Pressure Technique
• F1862-00a Standard Test Method for Resistance of
  Medical Face Masks to Penetration by Synthetic
  Blood (Horizontal Projection of Fixed Volume at a
  Known Velocity)

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Protection From Radiation Hazards

• Protection Against Nuclear Radiation
• The effects of large nuclear radiation can have
  severe, often fatal, consequences to human beings
  for short and long terms.
• Protective clothing designers must understand how
  radiation affects the body to determine the types
  and levels of protection needed.
• Types of radiation
• X rays
• Ionizing radiation
• Alpha, beta and gamma radiation
• Microwaves
• There is protective clothing against alpha and
  beta radiation, but not for gamma radiation.

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• Clothing for Nuclear Radiation Protection
• Protective clothing for nuclear power workers
  generally takes the form of completely
  encompassing coverall with integrated gloves,
  boots and hood.
• These anti-contamination suits are made of
  impermeable vinyl to closely woven materials such
  as cotton.
• Clothing for X-Rays Radiation Protection
• The material most commonly used in X-ray
  protective clothing is lead-impregnated vinyl. It
  is also possible to use antimony instead of lead
  because it is about four times lighter than lead,
  but antimony is more expensive.
• The protection offered by radiation-protective
  materials is expressed in millimeters of lead
  equivalency.

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X-rays Radiation Protection
Nuclear-radiation Protection
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• Protection Against UV Radiation
• Ultraviolet radiation (UVR), from the sun or
  artificial sources, is associated with problems
  such as carcinogensis, cataracts, sunburns, and
  photo-aging.
• UV-A radiation (320 to 400 nm) causes little
  visible reaction on the skin, but can decrease
  the immunological response of skin cells.
• UV-B radiation (290-320 nm) can cause sunburn and
  may be also responsible for the development of
  skin cancer.
• Factors affecting UV protection
• Fabric cover factor
• Fiber content
• UV-absorbent finishes

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• Testing UVR Protection
• Sun Protection Factor (SPF)
• UVR transmission 100 - cover factor
• SPF 100 / UVR transmission
• SPF 100 / 100 - cover factor
• Total UV transmission evaluated as a function of
  wavelength measured by a spectrophotometer.
• In order to calculate the SPF value from the
  transmitted radiation, two additional spectral
  factors must be taken into account The relative
  strength of the solar radiation as a function of
  wavelength and the relative erythermal response
  (reddening) of the skin to each given wavelength
  of light.