Exposure and products

Exposure

Health risks in the workplace is a major concern for both employers and employees. It is important to remember that some concentrations represent only health risk when they come in contact with your body. You can in other words avoid risk by eliminating or preventing contact.

Hazardous materials absorbed into the body in three ways:

• INGESTION - through the mouth
• ABSORPTION - through the skin, eyes
• INHALATION- through the lungs

The most common type of exposure for most health hazards are inhalation. This involves breathing in dust, fumes, oil mist, fumes from solvents and other various gases. To protect from this type of exposure you must either eliminate or prevent with different types of systems according to the wishes or comfort. Tenotec AS has 40 years experience in technical respirators and equipment covering most exposure types whether we are talking about dust, fumes, oil mist, fumes from solvents or other types of gases.

Breathing and inhalation

To better understand how harmful substances can enter your body by inhalation, let‘s take a closer look at the breathing process. Whenever you take a breath, oxygen rich air is taken into your body through your mouth and nose, goes down your windpipe and into the lungs. In your lungs, there are tiny air sacs called alveoli. These delicate air sacs then transfer the oxygen from air into your blood. At the same time the  oxygen is being absorbed into your bloodstream, carbon dioxide is being transferred from your  bloodstream into the air sacs. When you breathe out, you are ridding your body of  gaseous wastes.

The risk caused by airborne contaminants mainly depends on:

•The physical, biological and chemical properties of the contaminants, their size and form
•Concentration in the ambient air and time of exposure
•Volume of inhaled air (the more rapid respiration, the more airborne contaminants are inhal

What types of "air exposures" is possible to inhale?

Airborne particles - dust, smoke and steam: Workplace processes can generate tiny solid particles which are light enough to float in the air, and these arereferred to as dusts, fumes and smoke.

DUSTS are polydisperse solid aerosols*, generated during processing of organic and inorganic substances. Solid particles can be mineral, metal, coal, wood or crop dust, as well as fibres. They are usually heavy enough to settle slowly to the ground.

FUMES are very tiny solid particles which can remain airborne that are formed when a heated metal has evaporated in the air and then condensed back to a solid form. This occurs in welding and soldering
operations.

SMOKE is made up of small particles produced by the incomplete combustion of any material that has carbon in it. Smoke is often produced during processes that require high heat or burning as part of the manufacturing process. (* AEROSOL – a substance consisting of very fine solid particles or liquid droplets suspended in a gas.

Gases and vapours: Workplace chemicals can enter the air in a number of different ways. Simple evaporation is probably the most common way. Organic solvents, such as toluene, methyl ethyl ketone (MEK) or alcohols, generally evaporate more rapidly than water, acids or caustics, though this is not always the case.

GASES are materials that become airborne at room temperature. Gases may have an odor, but many do not. Some gases can be seen, but again, others cannot. Gases may be heavier than air, or lighter than air, but in either case, can travel for great distances undetected.

VAPOURS are substances that are created when a solid or liquid material evaporates. Materials that evaporate easily at room temperature include paint thinner or solvent


Negative pressure systems

Disposable particulate (dust) respirators

- Designed for protection against low concentrations of dust, mists, pollen, animal dust etc.

Advantages

  • Lightweight
  • disposable
  • relatively comfortable
  • and inexpensive.

Limitations:

  • Minimal protection due to poor sealing properties. They cannot be used by personnel with facial hair which comes between the respirator and the skin

Re-usable half mask

- Air purifying half masks have a rubber face sealing part which fits over the nose and under the chin. Exchangeable cartridges and filters are designed to provide protection against different types of air contaminants.

Advantages:

  • Relatively lightweight and offer good protection against many contaminants.

Limitations:

  • Use is limited by the type and capacity of the filters - can not be used neither in areas with high concentrations of contaminants nor in oxygen-deficient atmospheres. 
  • Difficult breathing because of the additional effort is needed to breath through the filters. 
  • Eye protection is not provided. 
  • Although the proper and tight fitting is essential, many factors may effect the face sealing

Re-usable full face mask

Air purifying Full Face Masks work on the same principal as the half-mask respirators described above. The facepiece extends protection around the entire face, covering the eyes, nose, chin and mouth.

Advantages:

  • Full face respirators are used where a higher level of respiratory protection is needed or where eye and face protection is required.

Limitations:

  • Full face masks are heavier than half-masks and often less comfortable for the wearer. 
  • Cannot be used for all types of air contaminants and are limited by the type and capacity of the filters and cartridges used. 
  • They cannot be used in oxygen-deficient atmospheres. 
  • Breathing may become difficult because of the additional effort is needed to breath through the filters.


Positive pressure systems

PAPR – Powered Air Purifying Respirators

- The most advanced group of personal protective equipment provides a high level of protection even for long lasting applications. Battery powered portable fan unit which drives the air through a particulate or chemical filter and blows it to the facepiece. Full and half mask are available as well as wide variety of hoods and helmets.

Advantages:
Major advantages are derived from the positive pressure provided by the fan forcing air into the facepiece, hood or helmet. This eliminates difficulty in breathing provided by the negative pressure respirators and reduces the importance of a good facial fit.

Limitations:

  • Higher purchase price and maintanance. 
  • Use is limited by the life time of the battery and fan. 
  • Can not be used in oxygen deficiency environments <19,5% O2 VOL

Airline systems

These respirators provide clean, fresh air to the user from a stationary source such as a compressor or compressed air cylinders. Full face mask and half mask are available as well as wide variety of hoods and helmets.

Advantages: 

  • Airline respirators may be used for long periods and provide a high degree of protection from a variety of air contaminants.
  •  They provide minimal breathing resistance and discomfort, are light weight, moderate initial cost and low operating costs.

Limitations: 

  • Unexpected loss of the air source eliminates all protection to the user.
  • Air must be delivered to the mask or hood through a hose which can be awkward to maneuver and may easily tangle or crimp. 

Applications: 

  • These respirators can be used for protection from the most of all air contaminants.

SCBA – Self Contained Breathing Aparatus

SCBA‘s provide the user with clean air from a high pressure cylinder carried on the wearer‘s back. They are equipped with a full face piece and are operated in the pressure demand mode. SCBA‘s provide the maximum degree of protection available from airborne contaminants.

Advantages:
Users carry their air supply with them allowing comparatively free movement over an unlimited area.

Limitations:
SCBA units are expensive to purchase and maintain; require the wearer to carry heavy weight of equipment on his back, and provide no more than 40 minutes of continuous use. Personnel with facial hair which comes between the respirator sealing surface and the wearer‘s face cannot use SCBA equipment