Health & Safety How to Stay Safe When Laser Welding Laser beam welding is a highly effective joining technique widely used across the welding and fabrication sector. The practice is underpinned by AS/NZS 2211.1 Laser Safety Part 1: Equipment classification requirements and users guide, which explains the risk categories and safety measures that must be adhered to when completing the practice. Weld Australia has also recently released a Technical Guidance Note to strengthen welder safety and provide practical tips in accordance with the Standard. Together, these safety guidelines and procedures explain the hazards, and the key responsibilities for equipment suppliers and welders who are conducting laser beam welding. Laser beam welding is a fusion process where two pieces of metal are joined together by a laser. The practice is common across the welding and fabrication sector, but it does pose a range of hazards. However, there are Standards and procedures in place to minimise the risks associated with laser beam welding. The basic approach to nearly all laser safety standards has been to classify lasers according to their hazard potential, which is based on their optical emission. According to AS/NZS IEC 60825.1 Safety of laser products Part 1: Equipment classification and requirements, laser manufacturers are required to certify that lasers are designated as one of eight risk classes, and labelled accordingly. Additionally, laser users are also responsible for acting in accordance with standardised safety measures to reduce or eliminate accidents. The following is a brief description of the categories of lasers (see also AS/NZS 1336). Class 1 A Class 1 laser is considered safe according to existing medical knowledge. They do not involve any hazard, and no safety measures are required. There are two subcategories under Class 1 laser systems: • Class 1C: These lasers apply where the beam directly impacts the intended target and engineering controls are applied to prevent leakage at levels higher than that permitted for Class 1. • Class 1M: Class 1M lasers exceed the emission levels of Class 1 lasers, but the beam divergence does not present a hazard to an unprotected eye. Importantly, if magnifying instruments like binoculars, telescopes, magnifiers, or microscopes are used to view the beam, eye damage can occur.
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Australian Welding
Class 2 Class 2 lasers or laser systems are defined as operating in the visible region between 400-700nm. These lasers are not typically safe, but protection against eye damage can occur through aversion responses like blinking. A very brief exposure, of around 0.25 seconds or less, is not considered hazardous. Class 2M lasers still operate in the visible region (400-700nm), but at higher power levels than Class 2 lasers. Because of the spread of radiation in laser beam welding, Class 2M lasers afford limited protection against eye damage because of the blink reflex and its response to bright sunlight. The blink reflex provides little protection, and the beam is considered hazardous if the beam is columnated by optics, or if it is viewed through optical instruments. These instruments may include binoculars, telescopes, magnifiers, or microscopes. Class 3 Class 3 lasers are medium-powered lasers, which may lead to a potential injury. Laser users who operate under this class may need to follow specific safety precautions, like wearing protective eye wear. However, skin hazards do not typically exist for incidental exposures under this classification. There are two subcategories under Class 3 laser systems: • Class 3R (Restricted): These lasers or laser systems can emit invisible or visible radiation and operate up to five times the power of Class 1 lasers (invisible radiation) or Class 2 lasers (visible radiation). However, they may have higher levels (25 to 50W.m-2) of radiant flux, or power. • Class 3B: Class 3B lasers can emit invisible or visible radiation and can cause eye injury.
