EWT - Line-Clearance Tree Trimming

According to the Centers for Disease Control and Prevention (CDC), during a 15 year period ending in 2007, a total of 1,285 worker deaths associated with tree care in the U.S. were reported to the Census of Fatal Occupational Injuries (CFOI), an average of 80 deaths per year.

Tree trimming is a necessary part of utility work, and it brings with it a variety of safety concerns, involving transmission line characteristics, safe tool operation, fall protection, and what personal protective equipment (PPE) to wear for the task. There is a lot that can go wrong when working in these high-risk, unpredictable scenarios. The key to safety with this important task is constant assessment, of personnel position, potential hazards, developments on the ground, and the electrical implements that need to be negotiated.

First, before an unqualified employee works around any tree, safety supervisors must determine what the nominal voltage is of any electric power lines posing a hazard to employees. Another way to do this, is to determine the maximum nominal voltage that an employee will be exposed to if all lines are considered energized at the maximum voltage.

Since chain and pole saws are the most commonly used instruments for vegetation removal, let’s run through some basics about safe operation of those devices.

Chainsaws

• Must be equipped with a chain brake and a protective device that minimizes chainsaw kickback (Do not disable or remove the kickback device).

• Must meet the requirements of the ANSI B175.1-1991 Standard.

• Must be equipped with a continuous pressure throttle control system that will stop the chain when pressure on the throttle is released.

• Must be operated and adjusted in accordance with the manufacturer's instructions.

• The chain saw should be fueled at least 10 feet from any open flame or other source of ignition, and then taken at least 10 feet away before it is started.

Operating

• Workers must keep both hands firmly on the handles of the chainsaw during operation unless employers can demonstrate a safer method for that particular situation.

• Workers should be certain of footing before starting to cut.

• Utility workers are not to use saws in a position or at a distance that could cause loss of control of the saw, or to slip or lose balance.

• Utility workers must not cut directly overhead—it is safer to reposition ladders.

Carrying

• Employees must shut down the chainsaw or engage the chain brake if conditions such as rough terrain, underbrush or slippery surfaces may create a hazard.

• Workers must carry the chainsaw in a manner that will prevent contact with the cutting chain and muffler, to avoid lacerations and burns.

• Prior to felling any tree, workers need to clear away brush or other potential obstacles that might interfere with cutting the tree or using the retreat path.

• Employees need to shut off or release the throttle before retreating back down ladders.

Other Notes

Tree trimmers, as well as their ladders, platforms, and aerial devices may not be brought closer to an energized part than the minimum approach distance for that situation—safe distance is a living saving priority here.

Branches that contact exposed energized lines or equipment, or that are within the minimum approach distance, may be removed only by use of insulated equipment. A tool constructed of a material that has tested insulating qualities is considered as insulated if the tool is clean and dry.

Each power saw weighing more than 15 pounds that is used for trimming trees should be supported by a separate line, except when work is performed from an aerial lift or during topping or removing operations where no supporting limb will be available.

Workers should not have a power saw running when carrying the saw up into a tree. They must stop the engine when cleaning, refueling, adjusting, or repairing the saw or motor, except if the manufacturer's servicing procedures say otherwise.

When an employee is working above the ground in a tree, he or she must be tied in with a climbing rope and safety saddle.

Weather

If there is a thunderstorm in the immediate vicinity, workers shouldn’t be performing this task. When adverse weather conditions make the work hazardous in spite of the safe work practices required, wait for better conditions—there is always other work to do. Depending on the season, lineworkers know that adverse weather is something that keeps them busy, from ice storms to lightning strikes. Under those circumstances, restorative work should only be performed when safely possible.