Segurança na Utilização da Tecnologia Ultravioleta
Ultraviolet technology has revolutionised the world of non-destructive testing (NDT) by making it possible to accurately detect and repair a wide range of defects that previously remained hidden.
UV technology can be used routinely and safely in NDT applications, with little chance of health risk, by following a few simple guidelines.
The term "ultraviolet radiation" may sound scary to some, conjuring up images of nuclear meltdowns and other disasters. However, without making it overly scientific, it is important to note that the term "radiation" is defined as "emission or transmission of energy in the form of waves or particles". In other words, light, radio waves, wireless signals or countless other natural and artificial energies are sources that
settle along the electromagnetic spectrum (photo) and constitute some form of radiation, each with its own uses and potential risks.
establish themselves along the electromagnetic spectrum (photo) and constitute some form of radiation, each with its own uses and potential risks.
Low energy waves are generally the most harmless and are used for radio and television transmissions, while high intensity X-rays and gamma rays pose the greatest safety risks - this high energy radiation is associated with the fears that many people associate with all radiation. Infrared radiation, commonly known as heat, is the most prevalent component of
sunlight, followed by visible light and then ultraviolet light.
sunlight, followed by visible light and then ultraviolet light.
The UV-A wavelength (365 nm), used in NDT or Nondestructive Testing applications, lies just above the upper limit of what the human eye can detect. When emitted onto a suitable reflective material, this UV-A wave can reflect visible light, making it very useful for seeing what the human eye alone cannot.
The simple act of walking outdoors already leads to exposure to UV-A radiation. Therefore, just as sunscreen is recommended for a trip to the beach or any other form of strong sunlight exposure, occupational exposure to ultraviolet light sources also requires simple and usual safety precautions.
In NDT applications, the most significant risk factor associated with exposure to UV-A radiation is to the eyes, as prolonged, unprotected exposure is associated with cataracts. Not looking directly at a UV light source is an important precaution, although the greatest concern with occupational exposure is reflected UV light.
Wearing UV absorbing glasses, supplied with inspection fixtures for NDT, prevents these reflected rays from reaching the sensitive eye tissue and is the most important safety precaution to take into consideration when working with UV lamps. Even if you never look directly into the lamp, without eye protection the reflected UV light will pass through the eye and could cause injury.
Excessive exposure to UV-A radiation can also potentially lead to skin cancer. Therefore, when carrying out regular NDT inspections, measures are required to protect the skin from reflected UV light, particularly by wearing long-sleeved clothing. It is essential to cover the skin as much as possible when working with the UV lamp.
Sunscreen can also be used for the face and other parts of the body that are difficult to protect with clothing, but it is important to choose a product specially designed to block UV-A rays for optimum occupational safety.
There is no formal occupational exposure limit for UV-A radiation, although guidelines set by the American Conference of Governmental Industrial Hygienists (ACGIH) are generally used as informal exposure limits. The guidelines are for NON-PROTECTED exposure and, although quite scientific, with the use of adequate eye and skin protection, should not come into play. Follow the links below, for more information.
As the risk of damage to the eyes can start with an exposure as short as 16 minutes, possibly less in the case of a high intensity source, the need for eye protection during occupational use of UV-A inspection lamps is highlighted.
The use of suitable protective eyewear, combined with the right clothing and sunscreen (where applicable) makes UV-A totally safe for routine inspection, allowing UV technology to be used freely and safely in a variety of NDT applications.
More information:
Columbia University, Health Sciences Division "Working Safely with Ultraviolet Radiation"
http://ehs.columbia.edu/UV.pdf
Canadian Centre for Occupational Health and Safety - Ultraviolet Radiation
http://www.ccohs.ca/oshanswers/phys_agents/ultravioletradiation.html
