Page 74 - OHS, July/August 2021

TRAINING: LOCKOUT/TAGOUT
Lockout/Tagout
Can Save Lives
Always consider the electrical issue as it relates to lockout/tagout.
BY JEFFERY BUCKAU
In the safety world, one tends to think of lockout/tagout as an electrical problem. People dealing with energized equipment spend significant amounts of time working through the de- energization process to ensure that electricians and quality
control people are kept safe from bolts of current flowing through conductors or components. As safety professionals, we need to always consider the electrical issue as it relates to lockout/tagout.
However, there are so many other items to consider when talking about the unexpected release of stored energy in the direction of workers. Some might call it a “line of fire” issue. A lot has been made of the avalanche issue from this past winter season. Snowpack on the side of a mountain has the potential for that unexpected release of stored energy. Millions of tons of snow sliding off the side of a mountain would surely have dramatic impacts on those in the way of the rushing snow slide.1 However, it isn’t like one could lockout/tagout the side of a mountain, right? Actually, you can. The ski patrol usually does this through proper signage and barricading.
At work, there are many times where stored energy is found near the worker. Gravity, chemical, high pressure, steam, hydraulic, mechanical, etc. are all found on worksites every day. If we were sitting in a classroom, a discussion could be held where examples for each of the items listed above would be explored. Stop for a moment and think of the last time you walked around your worksite and looked specifically for those areas where stored energy might be found.
One such example to discuss would be the case of the mechanic who was working on a cement truck.2 The truck had a mechanical problem where the mechanic had to climb under the rotating drum to complete the fix. The mechanic placed a “do not operate” sign on the steering wheel of the vehicle, the vehicle was turned off, and the key was removed. However, somehow someone was able to climb into the cab, remove the steering wheel sign and place another key into the ignition, starting the vehicle. As the
vehicle started the drum began to rotate and the mechanic was crushed between the rotating drum and the frame, a completely preventable and a totally unnecessary loss of life.
Another area where stored energy could occur on a construction job site would be in an excavation. A hole is dug creating a trench (deeper than it is wide) or excavation (wider than it is deep). The side walls have the potential of stored energy. With the side walls weakened, any slight pressure on the top of the side wall can create a downward sheer force causing the side wall to collapse into the hole. If it’s there by a worker in that area without proper protection, tragedy can occur. We all know that cave-in is the big issue here. The tons of dirt or material caving in around the worker can bury an employee, but it’s easily preventable.
What would be the lockout/tagout for this scenario? According to the current standards, there are plenty of safeguards in place for this. The 2,2,4,4,5,6 rule of thumb comes to mind.
■ The first two is placing spoil piles at least two feet from the edge of the hole. This helps keeps the shear force placed on the non-reinforced side wall of the opening to a minimum.
■ The second two is that when one is digging below a trench box more than two feet, the trench box must be lowered deeper into the hole.
■ Four: if the hole is four feet or greater then oxygen moni- toring must be completed to maintain the allowed concentration at 21.5 percent +/- 2 percent.
■ For the second four, if the hole is more than four feet, the hole needs an egress no greater than 25 feet from the worker.
■ If the trench is 50 feet long, how many egress points are needed? When the hole is greater than five feet, the hole side walls need to be either shored, sloped or benched.
■ And, if the hole is six feet or greater, fall protection must be used to prevent someone from falling into the hole.3
It is a best practice to provide barricades and signage around any opening in the ground to protect not only the worker, but
70 Occupational Health & Safety | JULY/AUGUST 2021
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