SLC 2018: Finding Alternatives to Lockout/Tagout
When safeguarding devices, there are many choices and references. It’s important to consider the task, the hazard and your options. If you pick the wrong safeguard, productivity suffers or somebody finds a workaround—and that increases your risk.
You can use the OSHA Minor Servicing Exception as an alternative to lockout/tagout (shutting the machine down completely to perform maintenance tasks), but you have to be careful how you do it. A risk assessment can help your engineering team design safe workarounds to lockout/tagout.
At the Safety Leadership Conference in November 2018, Steve Ludwig and Patrick Barry of Rockwell Automation shared safeguarding alternatives to lockout/tagout:
1. Fix the position of the operator. In the early stages of engineering on a new or refurbished machine, the positioning and the design of controls can prevent the machine’s operation while exposed. But problems can occur when two operators collaborate on a machine designed for a single operator. In that case, there’s not a lot to be done in the design phase to prevent exposure.
2. Prevent access by using a physical barrier. When that barrier is removed, the machine senses that and goes to a safe state. An interlocking guard can be used for certain specific tasks. For a more inexperienced worker, it may be beneficial to list the tasks on or near the machine.
With a locking gate switch, the machine stops when operator goes in. But if the operator is performing a cleaning task, the locking gate switch tends to be one of those things susceptible to operator bypass, which can cause safety issues.
3. Fix process conditions. Rather than shut everything off, find a condition to fix in place that keeps the person safe. For instance, if a gate is open, it will only turn in a different direction. This is where all the development is going on for manufacturers: Ways you can fix different conditions.
4. Install presence sensing. An electronic barrier can detect entry and stop the machine.