Methods of eliminating and limiting exposure

According to the regulation on health and safety at work related to the exposure to radiated optical [Journal of Laws of 2010 No. 100 item 643 and Journal of Laws of 2012, item 787] the employer is obliged to eliminate the occupational risk associated with exposure to optical radiation at its source or limit it to the smallest possible level, taking into account available technical solutions and scientific and technical progress.


The first principle of protecting employees from optical radiation is to avoid exposure to this radiation if it is possible. If this is not possible then the general principle of protecting employees against excessive exposure to this radiation is a combination of three basic types of preventive measures:

    • limitation of exposure time
    • ensuring the maximum distance between the employee and the radiation source
    • shielding from radiation.

Hierarchy of the above activities depend on the type of radiation source and the results of the occupational risk assessment. Whenever sources of optical radiation pose a threat to the health of employees, employers are obliged to provide them with protection against exposure by applying technical, administrative and personal protection measures. Technical means consist in designing and equipping workstations or technological processes to eliminate the occurrence of optical radiation in the occupational zone of the employee or to move people away from processes where there is a risk of optical radiation. An example of this is the installation of screens or protective covers, tight closing of the source in the machine's casing or a separate room, the use of various types of safety interlocks and materials with radiation absorbing surfaces, or radiation detectors and alarms (audible and / or visual).

 

Administrative measures include on: information and training of employees about the threat and protection against optical radiation, restriction of unauthorized access to the area where optical radiation may occur, limitation of exposure time and increase of workers' distance from the radiation source, introduction of warning signals and hazard monitoring through periodic measurements of radiation hazard optical at workstations, in accordance with applicable regulations.
If the technical and organizational measures do not provide adequate protection for the worker, then it is necessary to equip him with appropriate personal protective equipment. In the case of protection against optical radiation, eye and skin protection may be required. The exposed areas of the skin, especially the back, hands, head and neck, should be covered by appropriate working or protective clothing and hands - protective gloves.


However, clothing that protects against infrared radiation should be made of materials with high temperature resistance. The basic criterion for choosing the right protective clothing against infrared radiation is the intensity of irradiation that a worker is exposed to at a given position. Such clothing is usually used in steel mills and during fire fighting.


Eyes are protected by the use of goggles or protective goggles with filters properly matched to the wavelength of radiation and its intensity, while the combined eye and face protection is possible by the use of visors, shields or protective helmets.

 

The method of selecting eye and face protection equipment against ultraviolet light is performed depending on the radiation range and its intensity, determined on the basis of the MDE value exceeding. For high intensity UV-C and UV-B radiation sources, it is advisable to use eye and face shields. When using UV-A radiation sources, the use of eye shields is recommended. The method of selecting the right filters to protect against ultraviolet is presented in the PN-EN 170: 2005 Personal Eye Protection standard. Filters for protection against ultraviolet. Requirements for the transmission coefficient and recommended use. In the case of eye and face protection before infrared, the equipment is selected depending on the IR radiation range and its intensity, determined on the basis of the radiation source temperature, in the case of exceeding the statement of MDE exceedance. The selection of appropriate filters protecting against infrared is presented in the PN-EN 171: 2005 standard. Personal eye protection. Infrared filters. Technological infrared sources (such as, for example, molten metal, glass mass) in addition to infrared radiation can also emit intense visible radiation, which can cause glare. For this reason, the intensity of visible radiation should also be taken into account when selecting filters. The higher the filter designation, the greater the attenuation of visible radiation as well as the infrared. A specific case is the selection of equipment for eye and face protection used in welding and related techniques. In the case of electric arc welding and such techniques related to electroforming and plasma jet cutting, the choice of protection is based on: current, electrode type or welding technique (MIG, MAG, TIG) and the type of related process, according to PN-EN 169: 2005 Welding filters and filters for related techniques. Requirements for the transmission coefficient and recommended use. The choice of eye and face protection used in gas welding and such related techniques as brazing and oxygen cutting is made on the basis of the flow of oxygen or acetylene through the burner. Appropriate marking of filters used in gas welding and brazing and oxygen cutting are presented in PN-EN 169: 2005 Welding filters and filters for related techniques. Requirements for the transmission coefficient and recommended use.

 

In accordance with the regulation on health and safety at work related to the exposure to radiated optical in the event of exceeding the value of MDE, the employer is required to draw up and implement a program of organizational and technical measures to limit exposure to optical radiation, consisting of:

    • introduction of work processes or methods limiting occupational risks related to optical radiation;
    • selection of devices intended for performing a specific work, with the lowest possible emission of optical radiation;
    • limiting the emission of optical radiation with technical means, including the use, in necessary cases, of protective devices and other collective protection measures (locks, casings, screens, screens, etc.);
    • maintenance of devices that are a source of optical radiation emission and their equipment, protective devices and collective protection measures, as well as places and workplaces;
    • designing of workplaces and placement of workplaces in a manner enabling isolation from radiation sources and limiting simultaneous exposure to optical radiation emitted by many radiation sources;
    • limiting the duration and level of exposure;
    • ensuring properly selected personal protection equipment;
    • compliance with the instructions of the equipment manufacturers, in particular in the field of safe handling, preventing the creation of harmful emissions of optical radiation or excessive levels of exposure.

In addition, the employer means workplace safety signs in which the radiation level may exceed the MDE values, and give off zones with such places and restrict access to them if it is technically feasible.