Bill Hodgson, Safety Advisor
Safety Management Group
It goes without saying that industrial equipment can be dangerous when it’s being used. That’s why machines are designed with safety equipment and operators wear personal protective equipment when operating them.
But machinery can also present hazards when not in operation. As long as energy sources such as electricity, natural gas, steam, pressurized water, and compressed air are connected to the machine, a potential hazard exists. Workers who will maintain or repair the equipment, or who will be working in close proximity to it, need to be made aware of these hazards and assured that steps have been taken to protect them.
That’s why OSHA requires a formal lockout/tagout program. While it may seem that having a formal program with multiple steps may be overkill, it actually makes good sense. After all, most companies use a variety of equipment that require very different safety practices. In addition, any number of workers may be asked to deal with the equipment, and some will be more familiar with it than others.
Just as airline pilots with thousands of hours in the cockpit still go through step-by-step checklists before even the shortest flight – even though they could probably perform the actions in their sleep – having a detailed lockout/tagout set of instruction on how to properly remove from and return equipment to service is similarly important. It will help insure that nobody gets injured by the machine’s energy sources and can also prevent the machinery from potential damage.
When developing a lockout/tagout program, imagine that it’s Christmas night, and a contractor has been called in to perform an emergency shutoff of some complex machine. He’s never seen the machine before, and he can’t reach anyone from the company. By creating sound, detailed, clear instructions to guide a technician will have guidance that will prepare him for what he might encounter. He will be able to safely shut down the equipment.
The primary aspect of a lockout/tagout program is the equipment isolating instructions. These are developed by determining the correct procedure for shutting down and restarting the equipment. Spell out exactly what to do and in what order to safely de-energize, and then re-energize, that equipment. Determine these steps with operators and maintenance craftsmen most familiar with the nuances of the equipment. Detail that procedure, step-by-step, in writing. Consider all of the energy sources that may be connected to the equipment. Be very specific, because ambiguous language could lead to an incorrect and potentially dangerous action.
With any lockout/tagout program, it is incumbent upon management to supply sturdy locks and appropriate locking devices to secure valves, breakers, disconnects and the like in a de-energized mode. Quality locks and locking devices preclude an accidental re-energizing of machinery.
An effective lockout/tagout set of instructions will commonly include the following eight step approach.
Step 1: Detailed procedures for equipment
Begin the set of instructions on the proper de-energizing of equipment by making sure you’ve identified the equipment correctly and accurately, including its specific location. Emphasize the responsible craftsman must read and understand the procedure and pertinent hazards they will encounter. If they do not, then they must not attempt the lockout!
Step 2: Notify affected employees
When an equipment lockout is going to be performed, all of the employees that may be affected should be notified. Let them know the timing of the work, and how long the equipment may be unavailable. If the unavailability of the equipment requires a change in work processes, be sure they are familiar with the steps to be taken.
Step 3: Shut down equipment properly
The de-energizing procedure should explain the machine shutdown process in detail. It’s not enough to say a generic "shutdown or disconnect the machine." To ensure everyone’s safety and reduce the potential for damage to the equipment upon restart, the shutdown instructions should be detailed. Spell out the exact actions to be taken and their correct sequence to shutdown the piece of equipment.
Example: Move the On/Off selector on the Control Panel to the OFF mode, then de-energize the adjacent electrical disconnect labeled “XYZ”.
Step 4: Disconnect all primary energy sources
Although this may seem fairly self-explanatory, once again, it’s important to be very detailed. Whether the primary energy sources include electricity, steam, water, gas, compressed air, or other utilities, do not assume that the person performing maintenance will know the correct procedure to follow. Again, explain exactly what needs to be done, when and where. Since shut off valves can look similar and are often positioned adjacent to each other, it is a good practice to have each valve clearly identified. Reference that specific valve identity in the equipment specific lockout instructions.
Step 5: Address all secondary sources
While disconnecting the primary energy sources may remove much of the energy source dangers, there may remain sources of secondary or residual energy. Typical secondary energy sources include trapped heat in a thermal system, fumes that may need to be vented, free wheeling rotating assemblies, and tension in a spring assembly. Identify the process that will safely and effectively relieve or isolate these secondary energy sources.
Step 6: Verify the lockout
Once you’ve disconnected all primary and secondary sources of energy, attempt to start the equipment to verify that the lockout has rendered the unit dormant. This may be as simple as pushing the “Start” button. Before you try to start it, verify that nobody is in the area and it may be started safely. Once the lockout effort has been verified as successful, return all switches and associated equipment back to their "off" position. This is to preclude the machine starting unexpectedly when the energy sources are re-energized. Once you’ve verified the lockout, attach a lockout/tagout device to the equipment to ensure that it cannot be started without removing the device.
Step 7: Keep it in force during shift changes
The equipment must remain in lockout/tagout condition across shift changes, so that workers arriving at the site are aware that the equipment is out of service. If individual locks or tags are used, the individual(s) responsible for controlling the lockout/tagout on the current shift and the individual responsible for it during the next shift must both be present as the locks or tags are switched.
Step 8: Bring the equipment back on line
When the work is done the machine will be brought back into operation. Make a point of telling affected area personnel that the equipment is being brought back into service. The procedure should spell out the exact steps that are involved, along with the correct sequence. For example, one typically must open a discharge valve before you open the inlet, so any incoming product has a place to go.
A Key Additional consideration
Keep procedures up-to-date by periodic audits. Equipment and operating procedures tend to change. Over time controls may be updated, valves replaced and re-identified, and the like. Your lockout/tagout procedures needs to reflect these changes. That’s why it’s a good idea to review all your lockout/tagout procedures regularly to verify that they remain accurate. Even better is to have a strong change control process in place that will flag such changes and make the update of the Equipment Specific set of Lockout instruction a required consideration.
A company with just a small number of machines may be able to review all of them regularly, while a larger organization may need to study a certain number or a random sample every year. Another benefit of regular reviews is that it gives you an opportunity to deploy newer and better ideas or more accurate descriptions.
A well conceived and followed Lockout/Tagout program is not only an OSHA necessity, but a sound business practice. It will both keep your employees safe and ensure properly sequenced shutdowns and restarts that protect your operating equipment.
Bill Hodgson (BillHodgson@SafetyManagementGroup.com) is a Safety Advisor for Safety Management Group, an Indianapolis-based professional service organization that provides nationwide workplace safety consulting, training, staffing, program planning, and implementation. Information is available at www.safetymanagementgroup.com/pub or by calling 800.435.8850.