Homeowners have a love affair with their power equipment and spring ushers in a multitude of opportunities to put them to work. Unfortunately, safe operation of this equipment is often overlooked or misunderstood.
Chainsaws are one of the most dangerous tools that a homeowner can operate. When contemplating the use of a chainsaw, users should consider not only the operation of the saw as a potential danger but the consequences of what they are cutting. As the process of felling trees is far too complex for an article of this type, we will concentrate on some basic chainsaw safety.
The first and most important aspect of safe chainsaw operation is to be wearing proper Personal Protective Apparel or PPA. The minimum standard includes: helmet, hearing protection, safety glasses, chaps/chainsaw pants, steel/composite- toed full leather boots, and gloves.
The chain on a chainsaw can move at a speed of over 9000 feet per minute. In an instant, a chain can impart considerable damage to human flesh. Further, studies show that injuries to the leg and knee during chainsaw operations account for a third of injuries. In order to mitigate this type of injury, chainsaw pants have been designed with a special fibre that when contacted can stop a chain from moving in under one second. This has considerable value when you consider the fact that of the 35,000 admissions to hospital for chainsaw injuries in the U.S. in any given year, the average number of stitches administered is 110.
There are a number of reactive forces that occur as the cutters on a chain chisel and cross cut wood fibres. The most significant of these reactive forces is kickback. Kickback can have lethal or life changing consequences and should be well understood before operating a saw. It occurs when the upper tip of a chainsaw bar contacts any type of material including wood. When the cutters of a chain rotate around the bar tip, the guides that control the depth of cut momentarily lose their functionality, and can result in a violent upwards rotational force towards the operator. For this reason, the upper front tip of a bar should never be the first part of the saw introduced into material to be cut. If it should happen inadvertently, there is no way to respond to it quickly enough and a helmet and/or chain brake are often the only saving graces.
Over the years, engineers have incorporated at least four safety features into modern chainsaws. They include: 1) an inertial chain brake 2) a throttle interlock 3) a chain catcher pin and 4) a wrist protector
The inertial chain brake is a feature whereby the chain brake will engage should a rapid kick back event occur. The chain brake should be engaged at all times when the operator is not cutting. This is especially significant when an operator is moving or starting a saw. If taking more than one step while the saw is idling, I will always engage the chain brake. In the event of a fall or trip it would be impossible to have the chain move even if the throttle was accidentally activated because the brake is on.
The throttle interlock is intended to prevent operation of the saw without the operator’s hand in the proper position.
The chain catcher pin is a safety feature that is meant to catch or slow a chain dislodged from the bar.
The wrist protector is a widened area of plastic below the handle of a saw that, in conjunction with the chain catcher pin, prevents a thrown chain from rotating up into the operators hand.
Lastly, a comment on the starting of a saw. All too often I see operator’s performing a drop start, which is neither a safe or acceptable chainsaw starting method.
The two safe and standard starting methods are the ground and leg-lock start. My preference is the leg-lock start which provides three points of contact with the saw and a stable body position. The chain brake should be on, the left hand on the top bar, the chainsaw rear handle cradled between the legs, and the starter cord pulled straight and in such a way that it doesn’t rub against any of the housing. These techniques can be viewed at: www.youtube.com/watch?v=THV_xf Fe0i8
This short article is meant to be an introduction to chainsaw safety and is not a substitute for formal training. Chainsaw operators should be very familiar with their chainsaw’s operating manual and understand not only the limitations of their equipment but their own abilities as well.
Jeff Hughes is a Certified Chainsaw Trainer and Owner of TreeWorx Tree Care Inc.
