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Personal Protective Equipment for the Face and Arms
 
 
Personal Protective Equipment for the Face and Arms

HAND AND ARM PROTECTION

Personal protective equipment which is designed for the hands can also consist of protection of the arm in the form of gauntlets. They may be designed to protect the wearer against the following hazards:

  • Physical hazards
  • Environmental hazards
  • Chemical injuries
  • Biological injuries
  • Thermal injuries
  • Electrical injuries
  • Radiation injuries

Hand protection can be made of the following designs:

  • Five fingered gloves
  • Two fingered gloves
  • Mittens
  • Fingerless gloves
  • Partial gloves
  • Finger guards
  • Finger cots
  • Hand pads

Some examples of hand protectors include the leather work glove, the cotton work glove, the unsupported rubber glove, a rubber-coated fabric glove, the steel ribbon reinforced mitten and the fingerless leather glove.

The five fingered glove provides the greatest protection of the hand against the various hazards the worker might be exposed to. Mittens, on the other hand, are often used in extremely hot or cold environments to provide thermal insulation. The partial glove protects the wearer's palm and fingers but has an open back. Fingerless gloves protect the patient's palm and back of the hand but leave the fingers free for better functionality. They can protect the hand from cold or from physical hazards.

Finger guards have an elastic back and an open end or wrap around the finger with an elastic back, protecting the entire finger. There are also those that roll onto the finger and protect the finger all around. Finger guards often protect against physical injury. Finger cots usually protect the entire finger, extending over the first interphalangeal joint. Hand pads are usually protective against the palm of the hand only but can be made to protect the back of the hand as well. Many are rectangular in shape and protect the front and back of the hand. Hand pads protecting the palm only are attached at the fingers or thumb and around the wrist with an elastic band.

Gloves and other hand gear are made from the following materials:

  • Leather
  • Cotton or other natural textile
  • Synthetic fiber knit or woven material
  • Aluminized fabric
  • Rubber coated or impregnated fabrics
  • Rubber
  • Plastic
  • Metal mesh

Gloves may have linings to enhance comfort or to provide a method to wick away hand perspiration; barriers marries may prevent liquid penetration or may provide insulation from severe heat or cold.

GLOVE CONSTRUCTION

Gloves can be made of a separate glove liner and therefore is made in two pieces. The "clute cut" glove is made with a single piece as the front of the glove while the back is sewn from a number of pieces. This provides a form-fitted glove that generally has a knit wrist. The "Gunn cut" glove is made by creating the back of the glove liner from a single piece. "Dipped gloves" are made from dipping a metallic or porcelain form into a vat of rubber to create a molded rubber glove.

Cuff designs can have various functions and include knit wrist cuffs that keep debris out of the glove. They fit relatively snugly around the wrist. Safety cuffs provide an extended piece of material attached to the glove by a seam at the wrist. Unlike knit wrist cuffs, they are typically made of more rigid material that remains firm, eve with perspiration and are easier to get on and off more quickly than knit wrist cuffs. Gauntlets are similar to safety cuffs but extend up to the lower forearm. Closure-end cuffs have an open end that is secured around the wrist with a closure such as a hook and loop or an adjustable strap.

HISTORY OF HEARING PROTECTION

It was in the military that initially spurred the invention of hearing protections, which was believed to be used as early as ancient Greek times. In 1864, earplugs were patented and ear canal caps were attached to an adjustable headband for sailors and soldiers. The first disposable earplugs were designed for WWI soldiers and were patented in 1914. Leather flaps were used over the ears to protect the crews of military aircraft. Earmuffs were designed for those who were near jet engines, and are still used today. Such earmuffs require a strong and stiff headband to allow a tight seal against the wearers head. A fluid-filled cushion for a headband muff was first designed in 1954 for a better seal. Comfortable foam earplugs were first created in the 1970's.

HEARING PROTECTION TYPES

There are generally three types of hearing protection:

  • Ear plugs that fit directly into the ear
  • Ear canal caps that cover the external opening
  • Ear muffs over the ears

There is a newer class of hearing protectors that include active hearing protective devices.

Ear Plugs come in three types:

  • Formable
  • Custom-molded
  • Pre-molded

Conformable earplugs come in foam, fiberglass or silicone materials and form to the ear canal upon squishing the earplug and inserting it into the ear, whereupon the earplug expands to fit the ear canal snuggly. They are usually one size fits all and are usually designed to be disposable. Many are single use only. They require wearer cleanliness upon insertion to prevent infection and care should be taken to prevent ear damage upon insertion.

Custom-molded ear plugs are specifically-molded to the wearer's ear. It achieves a complete and total fit for the person to which it is molded. Such earplugs are not disposable and are intended to be used indefinitely.

Pre-molded earplugs are comprised of silicone, urethane or vinyl material and often include one or more flanges that help seal the ear canal. They can be of a universal size, fitting a wide variety of ear canal shapes and sizes. They may also come in a variety of sizes to mold different sized ear canals. It is probably best to have a professional fit this type of earplug so as not to damage the ear.

Earmuffs can be attached to a head band or to the sides of a hard hat. There can also be headbands that are connected to earplugs rather than ear muffs. Earmuffs are dome-shaped devices that fit directly over the external ear, including the earlobe. The cups are made of a type of plastic and are padded on the inside to protect the hearing. The cushioning material is made of foam; however, some companies are offering liquid encased in a plastic or rubber material that improves the seal over the ear. The headband can fit under the chin or over or behind the head. Some earmuffs are equipped with microphones, speakers and amplifiers--communication sets not unlike those used in the aircraft industry.

Most ear muff manufacturers utilize an oval rather than round ear cup that fits the majority of the worker population.

Active hearing protective devices resemble ear muffs but are used to overcome communications difficulties, having exterior mounted microphones with amplifiers that pick up ambient sounds and deliver the sounds to the wearer by the use of ear phones embedded into the ear muffs. They can selectively filter or modify the level of sound based on frequency of the sound.

RATING EAR PLUGS

Earplugs are rated with an NNR or Noise Reduction Rating. An NNR tells you how much noise reduction in decibels the set of earplugs provides. An average NNR for earplugs is 26 to 33 decibels.

Respirators

A respirator is a PPE device which is designed to protect those who wear it from the inhalation of harmful fumes, vapors, dusts and gases. They are primarily used by the military and in private industry. Respirators can be single use devices or reusable types that have replaceable cartridges for filtration.

There are two main categories of respirators:

· Air-purifying respirator--it forces contaminated air through a filter, delivering clean air to the wearers respiratory system

· Air-supplied respirator--it provides an alternate supply of clean air to the wearer

There are also combined respirators that combine the features of each.

HISTORY OF THE RESPIRATOR

The first respirator was designed by Leonardo da Vinci in the 16thcentury. He felt a finely woven cloth which was dipped in water could be used to protect sailors who worked with a fine powdery substance. In the mining industry, a primitive respirator was used in 1799, invented by Alexander von Humboldt. Most respirators of the era consisted of a rubber, impregnated fabric or rubberized fabric that was placed over the entire head and fastened around the throat. Many contained a tank with slightly positive-pressure air, while others also had the means to absorb carbon dioxide in exhaled air. Others just had valves for used air to escape.

The first patent for an air purifying respirator was given in 1848 for the "Haslett Lung Protector" that filtered dust using a one-way clapper valve and a moistened wool filter. Later cotton and charcoal or lime filters were patented. Charcoal or lime filters were used to absorb poisonous vapors. Eventually, activated charcoal became the gold standard for respirator use. In 1871, a firefighter's respirator was developed which used cotton and wool, saturated with lime, charcoal and glycerin, which filtered smoke and gases from the air.

Poisonous chemicals were first used in WWI, when the Canadians pushed back the Germans by releasing toxic chlorine gas, killing almost 6000 troops within ten minutes. The gas caused blindness and respiratory failure when troops were exposed. Chlorine is denser than air so that the poisonous gas flowed down into the trenches. The Canadians survived by using urine-soaked cloths to make primitive respirators. The ammonia in the urine neutralizes the chlorine so the soldiers could breathe through the gas.

An American inventor, Garrett Morgan, patented what he called the Morgan safety hood and smoke protector in 1914. It was used in mining and, in fact, was responsible for saving more than 30 trapped miners only two years later. This lead to designs used in firefighting and in WWI.

A carbon monoxide respirator was created by the British in 1915, just before the heavy use of chemical gas weaponry. It was found that unexploded enemy shells gave off deadly carbon monoxide gas that killed soldiers in confined spaces. In 1916, the British created the British Small Box Respirator or SBR that became one of the most widely used and reliable gas masks created in WWI.

MODERN RESPIRATORS

Modern respirators are either tight-fitting or loose-fitting and provide the ability to remove contaminants from the air while supplying fresh air from an alternative source.

Tight-fitting respirators are face pieces that provide a gas-tight and particle-tight seal on the wearers face. They are generally made from a moldable elastomer material and include:

· An elastomeric face piece

· Straps or head bands

· Valves (optional)

· Connections to air purifying or air supplying elements

Some respirators are constructed from fabric that has the same level of protection as elastomeric respirators.

The face pieces may be of four different types:
· Half-mask facepieces: They cover the nose and mouth and have a seal that fits just beneath the chin.
· Full facepieces: They cover the wearer's mouth, nose and eyes and are sealed all around
· Quarter-mask facepieces: They cover the wearer's nose and mouth and have a sealing surface that resides between the lower lip and the chin.
· Some respirators just have a nose clip and a mouthpiece which are generally used just for escape.

Full-face respirators may come with a nose clip to allow for positive pressure ventilation and to prevent fogging of the respirator from nasal moisture.

Loose-fitting respirators look a lot like clothing and are made of fabric. They come in five different types:
· A loose-fitting cloth face piece that covers a portion of the head.
· A helmet that covers the head (with rigid material) and protects the head from injury.
· A hood that is made from flexible fabric that covers the head, neck, and shoulders.
· A blouse that covers the head and upper torso and may or may not contain arms.
· A suit that covers the wearer's entire body.

Loose-fitting respirators must work under sufficient positive pressure and are used with air-purifying respirators or atmosphere-supplying respirators. Respirators that rely on a secondary source of air are classified according to their time of service, which can range from three minutes to four hours. Air-purifying respirators cannot be used if the ambient environment contains less than 19.5 percent oxygen.

Types of air purifying respirators include:

· Non-powered APRs that only operate through the breath of the wearer. Ambient air is pulled through the filter when the wearer inhales. Exhaled air goes through an exhalation valve or back through the air purifying filter.

· Powered APRs are equipped with a blower that is either portable or fixed and blows air through the air purifying element and supplies air through the respiratory inlet covering.

There are eight different air-purifying respirators:
1. Gas masks
2. Non-purifying particulate respirators
3. Pesticide respirators
4. Chemical cartridge respirators
5. Paint spray respirators
6. Dust, fume and mist respirators
7. Powered air-purifying high efficiency respirators
8. Combination gas masks
Air purifying respirators have the ability to be:
· Particle-removing
· Gas/vapor removing
· Combination particle-gas-vapor removing respirator
Particle-removing air purifying respirators are made from a fibrous material that removes particles through the use of:
· Gravity settling: it changes the particles path
· Impact: the particles impact the fibers and get stuck
· Diffusion: the random motion of particles entraps them in the fibers
· Sieving: large particles are trapped in spaces of the media
· Electrostatic attraction: the particles are held onto the fibers through static electricity
Gas-vapor removing air-purifying respirators utilize solid materials that remove the gases or vapors by the use of:
· Absorption: the gas penetrates the solid and is held in place.
· Adsorption: the gas is held onto the surface of the solid.
· Catalysis: the gas reacts with the solid to become non-toxic.

Atmosphere-supplying Respirators provide an external air or oxygen supply to the respirator. They work in situations where the air is contaminated with toxic particles, is of an extreme temperature or is oxygen-deficient. It is a commonly used device in firefighting.

Such devices include the following:
· Supplied-air respirators
· Self-contained breathing apparatus (SCBA)
· Combination devices
Supplied-air devices use a source of air which is stationary and is supplied to the wearer of the device through a long tube. Air is supplied through an airline or through a hose-mask device. There are three such types of supplied-air respirators (SARs):
· Airline SAR connects the air source to the respirator inlet and supplies a continuous flow of air or oxygen that is determined by an adjustable valve.
· Demand airline SAR is equipped with a tight fitting facepiece. A valve allows air to supply the respirator only when the wearer inhales. The flow of air is stopped during exhalation while maintaining a positive pressure within the facepiece.
· A Pressure demand SAR is like a demand respirator except that the regulating valve maintains positive pressure throughout the respiratory cycle. This keeps the valve open to some degree at all times.
A hose mask SAR supplies air through a large diameter flexible tube and comes in two basic types:
· Hose mask SAR that has no blower but has a tight fitting facepiece connected to a hose that is limited to 75 feet.
· Hose mask SAR that has blowers that push air through the hose and has an extended length of up to 300 feet.

Self-contained breathing apparatus (SCBA) uses a source of air or oxygen that is carried on the body of the wearer of the respirator. Most use tight fitting full face pieces and the wearer is independent and mobile. The use of the device is independent of the ambient temperature. There are two types of SCBA:

· Closed-circuit SCBA remove the carbon dioxide from exhaled air and restores the oxygen content of the residual air.

· Open-circuit SCBA uses a portable compressed air cylinder that provides air to the face piece in either a continuous-flow device, a demand device or a pressure-demand device, that maintains a constant positive pressure, even during exhalation.

 
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