Have you ever been working in the basement when someone upstairs turned the lights out? Suddenly you’re in total darkness, and your immediate reaction is to let out a yell. This usually brings the lights back on, along with an apology from the person who absent-mindedly flipped the switch. In this case, there’s usually no harm done. But what if you were checking a machine and someone flipped a switch that started gears turning and they chewed up your arm?
This type of accident happens all too frequently. Each time it points up the fact that shutting off machinery isn’t enough–you have to lock out the main switch and tag it.
Actually, there are several reasons why a machine may run after it apparently has been shut off. The machine can coast or it can cycle by gravity. The switch might also be bypassed by electrical wire, or the machine might cycle if air or hydraulic pressure lines have not been bled off. And, of course, if you don’t tag and lock out the main switch, someone may unthinkingly turn on the switch, causing the machine to suddenly go into action at a very bad time for you.
What can you do to protect yourself and others?
- First, before attempting to adjust or repair a machine, wait until it comes to a complete stop. Block the elevated ram or other mechanisms so that they can’t be operated by gravity. Bleed air and hydraulic pressure lines. Then lock out the main switch so no live wiring can be contacted actually. Push the start button to make sure the machine will not cycle.
- Finally, attach a tag to the switch stating your name, department, and reason for taking the machine out of service.
To repeat, the basic sequence for lockout procedure is:
- Disconnect and tag the main control of the entire unit to be worked on. Use padlocks if possible, (each person working on the equipment should have their own lock and key.)
- Disconnect all plugs and cords on portable units. Attach your tag, starting time, department, and reason for repair.
- 3.Bleed air and hydraulic lines, block all rams, and lock out main valves. If working on the plant, get the dispatcher to give you the auto control key.
- Test the machine to make sure it will not cycle. Then perform the necessary adjustment or repair. After repairs or adjustments are completed, replace all guards and safety devices. Remove only your own padlock and tag. (This is very important if more than one repair person is working on the machine.)
- When all is clear, restore power and check-run the equipment.
If the repairs aren’t satisfactory, repeat all previous lockout steps again.
It is important to remember that the tag and lockout devices should be removed only the person who originally attached them. The supervisor, after checking the situation thoroughly, may remove these devices in case of illness or absence of the persons who attached them.
Many people don’t want to take time to go through the safe lockout procedures. Others may hurriedly attempt to make adjustments that they aren’t authorized to handle, while still others don’t shut off machines before making repairs. Sooner or later people in a hurry are involved in accidents.
Never assume that other people will see you make adjustments and will know that they shouldn’t turn on the machine. They may be too absorbed in thinking about their own safety to recognize any danger to you.
“Practice safety–don’t learn it through Accidental Experience.”