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SEP-OCT 2018

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perimeter guarding around the entire process. However, in most situations, a machine operator needs to interact with the process by loading or unloading materials (such as metals to be weld ed) and "running" the machine. Point-of-operation guarding is where things get tricky. Many details must be considered when it comes to this area, including the layout or design of the process and the limits of the system. Also, facilities must properly identify all associated haz- ards and devise methods for hazard elimination and risk reduction. Once the severity of the potential hazard has been determined, the frequency or duration of exposure and the possibility of eliminating or lim - iting exposure should be considered before mak- ing any machine guarding decisions. Also, using the distance formula identified in OSHA guide - lines can help in this analysis. Per this formula, the safeguarding device has a prescribed location based on a number of factors, including second - ary hazards that might harm a machine operator. Presence-sensing devices Light curtains, laser scanners, and other presence- sensing devices are a commonly used and widely accepted method of machine guarding in manu - facturing facilities—from tier 1 automotive to small machine shops and fabrication facilities. With presence sensing, the automated process ceases once the safety device's infrared beam is tripped. These devices often provide acceptable safety. RIA R15.06-2013 When it arrived earlier this decade, the RIA R15.06 standard made life easier for manufacturers and end users by being compliant with international standards already in place in Europe. RIA R15.06- 2013 references ISO 10218-1 & 2, which addresses robots, robot systems, and integration. This stan - dard requires better hazard identification related not only to robotic motion, but also to the task be - ing performed. Additionally, it requires validation and verification of the safety systems employed and requires designs that incorporate protective measures for the robot cell and the operator. Some of the biggest changes with the RIA R15.06 industrial robot standard have to do with safety- rated motion and allowing advanced programma- ble safety devices to be used. This means software is allowed "safety-rated" control of various aspects of the robot's function, limiting the area in which the robot operates and the speed of robot motion. This is a departure from older standards, which did not allow programmable safety controls. As mentioned earlier, risk assessments are re- quired as part of this standard. Many professionals responsible for plant safety have been conducting risk assessments to increase safety as a matter of practice; the new regulations mandate them. Point-of-operation danger When performing a proper risk assessment, point-of-operation guarding is probably the most involved aspect. It is relatively easy to place FACTORY AUTOMATION FAST FORWARD l Point-of-operation dangers become much more apparent after a proper risk assessment. l Are you taking advantage of "safety-rated" control allowed by RIA R15.06? l Physical barriers can improve worker safety by minimizing primary and secondary hazards that are common to hazardous work cells. INTECH SEPTEMBER/OCTOBER 2018 23

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