When using laser equipment in industry, it is important to adhere to the requirements that ensure occupational safety! Meeting the conditions outlined in international standards in a laser work environment is critical to ensuring a safe working environment for operators, people in the immediate vicinity of the laser system, and the equipment.
The most basic standard document for classifying lasers is IN 60825-1: 2014 with its accompanying T11: 2021 with amendment. The EN60825 standard focuses on lasers with a wavelength range of 180 nm to 1 mm, for lasers with lower wavelengths a vacuum environment is required, the design of which already ensures the necessary safety requirements. Attention has been paid to safety for the skin and the eye in the particularly dangerous wavelength range of 400 nm to 1400 nm. According to the standard, it is also determined that a laser is of the continuous wave (CW) type if the pulse length exceeds 0,25 seconds ON-time. A pulsed laser (PL) is considered a laser with a pulse shorter than 0.25 seconds. Both types of lasers are used in industry, the pulsed laser is used for spot welding and laser cleaning, as it is possible to achieve higher peak power to melt the material without changing its properties as a result of thermal processes and to keep the average energy consumption low. The advantage of continuous wave lasers lies in high-speed edge welding and cutting of materials.
The term by which lasers are classified is the Accessible Emission Level (AEL), which is measured in watts. According to the standard, there are 4 main classes, the first three of which also have subclassifications. The highest, Class 4, has no subclassification. You can read more about the classes in our previous article “Laser hazard classes and corresponding protective equipment". Also, according to the EN 50689:2021 standard, all Class 4 laser devices are professional tools.
When creating protective and safety systems for laser devices, a risk analysis is prepared, which assesses the probability of an error occurring and the level of danger of the error. The lower the level of danger of the error for the user, the more errors are allowed to occur without the need to change the laser class of the device as a result. In the case of class 4 protective systems for laser devices, every possible error that lies in the direction of possible rapid movement is taken into account. In the case of class 4, the housing surrounding the laser is also assessed and whether the laser can affect or damage the surrounding housing.
According to the standard, every Class 4 laser device must have:
- A designated Laser Safety Officer (LSO) within the company who is knowledgeable about laser hazard assessment and control and is responsible for overseeing the control of laser hazards.
- An enclosure capable of withstanding the power output of the device for a sufficient period of time to allow the operator to interrupt the laser operation. The enclosure is permitted to emit laser power below Class 1 radiation.
- Components that require maintenance on the device and the removal of which provides access to the radiation class of the device and do not have a locking mechanism must be removable or movable only with a tool or tools.
- The enclosure panels shall be equipped with safety sensors and a locking mechanism to interrupt the laser beam when the panel is removed or opened. When the panel is open, the transmitted radiation shall not exceed Class 3R radiation. When the locking mechanism of the device is disengaged, the emitted radiation may be higher.
If the machine has a safety override system from the manufacturer, the manufacturer must have sufficient material and information for safe operation with the laser. When the panel is replaced, the locking mechanism must be restored (preventing a false-safe situation). - External safety sensor that interrupts laser radiation to Class 1M or Class 2M levels when the terminals are opened. This requirement does not apply to hand-held and battery-powered Class 3R devices.
- Manual reset button to restore laser radiation by the operator in cases where the laser beam is interrupted by an external safety sensor or a power supply failure lasting more than 5 seconds.
Keyed main switch, the key must be removable and laser radiation must not be available when the key is removed. - An audible or visual warning device when the laser device is switched on or when the capacitor bank of a pulsed laser is being charged or is not fully discharged. The device shall be fail-safe or of a dual system. Visual warnings shall be visible through protective glasses and goggles designed for the appropriate wavelength. The visual warning shall be positioned so that viewing it does not require exposure to radiation higher than 1M and 2M. Control panels or openings located 2 metres or more from the laser device shall be equipped with separate radiation warning devices.
- The device shall have one or more permanent means of stopping the beam. This may be by means of fixed beam stop(s), dampers, electronic control or switch. The beam stop, damper and switch shall be capable of stopping access to Class 1M and Class 2M radiation.
- The controls for controlling the beam must be installed in such a way that their use does not require the operator to be exposed to laser radiation higher than Class 3R, Class 3B or Class 4.
- Optical elements, shutters and screens must provide sufficient attenuation to prevent operators from being exposed to radiation stronger than Class 1M.
- If the device has a panel that allows “walk-in”, the device must:
- A system must be installed that prevents laser radiation exceeding Class 3B and Class 4 from being initiated internally.
- A warning system that would provide sufficient warning of laser radiation to a person inside the machine.
- If “walk-in” during operation is foreseeable, the device must be equipped with engineering methods (pressure mats, infrared sensors, etc.) to exclude Class 3B or Class 4 laser radiation inside the machine.
Meeting these conditions in a laser work environment is critical to ensuring a safe working environment for operators, people in the immediate vicinity of the laser system, and the equipment!
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