Chopping Chain Saws

Archive for the ‘Safety’ Category

Despite all the safety improvements that have been made with chainsaws in the past few years, chainsaws are dangerous.

An average of 40,000 individuals are injured each year in the USA because of misuse of chainsaws, with most injuries occurring from kickback. This is occurs when the upper tip of the guide bar touches an object or when the wood pinches the saw chain in the cut, resulting in the bar violently being driven in an upward arc towards the operator. Kickback has resulted in serious injuries and even deaths.

In addition to kickback, chainsaws can also cause the operator to have vibration white finger also referred to as hand-arm vibration syndrome or HAVS, which can result in permanent numbness in the fingers, other systems cause by chainsaws include tinnitus, and industrial deafness.

In order to help reduce the number of injuries and improve the safety of chainsaws, manufacturers have installed several safety features. Some of these features have become standards, while others are legal requirements set fourth by certain state and federal, and national jurisdictions and governments.
The following is a list and brief description of the safety features on most modern chainsaws:

On/Off Switch

Because of past accidents where the on/off was accidentally shut off during a critical point in tree cutting, most on/off switches today are clearly marked and positioned so that there isn’t any chance the switch will accidentally be turned off, even while the saw is vibrating under a heavy load.

Front Hand Guard

The front hand guard is a bar that is in front of the top handle. It is designed to stop a slipping hand from coming into contact with the saw chain. When the operator is using the chainsaw, a right-handed person will always keep the left hand on the front handle, and visa-versa for a left-handed operator. If the operator accidentally loses his hold, the front hand guard will help prevent his or her hand from moving forward and into the saw chain. On several models of chainsaws, the hand guard also operates the chain brake, shutting off the saw chain when the hand guard is pulled back towards the user.

Manual or Inertia Chain Brake

The chain brake is designed instantly stop the saw chain dead, even with the chainsaw’s engine operating at full throttle. Once the chain brake has been engaged, the operator must deliberately switch off the chain break. In February 1995, all chainsaws sold in the United States must be equipped with chain brakes. Every year an estimated 40,000 people are seriously injured or killed as a result of chainsaw accidents. Unfortunately, all of these accidents could have been avoided.

The chain break is to prevent or reduce the risk of injury when kickback occurs. This is when the upper portion or tip of the chainsaw strikes an object, or is used for cutting. When kickback occurs, the tip of the chainsaw cutter bar is jerked violently up and back toward the operator, making the chainsaw very difficult to control. When this happens, the chain break is engaged, stopping the saw chain, so that if the saw chain hits the user’s arm, head, shoulder, or other body part, the cutting chain should be stopped, and the minor.

Today, many modern chainsaws have incorporated an inertial sensor and mechanism, which switches the chain brake on when kickback occurs. The sensor detects the characteristic rapid rotation of kickback, and engages the chain brake by automatically pushing the hand guard forward. Sadly, many chainsaw owners have taken upon themselves to disable this safety feature. Statistics from insurance companies have shown that of the reported injuries resulting from chainsaw accidents—40% of the chainsaws involved, had the chain brake removed, or disabled.

Safety Throttle

The safety throttle is designed to prevent the saw chain from being driven if the trigger has accidentally been pushed by an obstruction, such as a branch or undergrowth. The throttle is locked in the idling position when the proper handgrip is not engaged on the handle.

Chain Catcher

The chain catcher is located on the bottom most forward position of the engine and is designed to prevent the chain from being thrown back towards the user, if the chain breaks or becomes derailed.

Anti-Vibration System

Individuals who operate tools, which produce excessive vibration for over long periods of time, can develop hand-arm vibration syndrome or HAVS, also known as white finger. This is a condition that can cause permanent numbness in the hands and fingers and is a debilitating industrial injury. To reduce the risk of HAVA, manufactures have divided the chainsaw into two parts. The first section is the cutter bar and engine, which vibrates strongly when the chain is cutting. The second section is the assembly of the handles and controls, or the section the operator holds. These two sections are joined together by mounts that provide spring suspension and damping to the chainsaw. These mounts are often rubber bushings but may also be constructed of metal springs.

Exhaust/Muffler

The exhaust or muffler servers two purposes. The first is to direct the hot and harmful gases coming from the engine and operator. The second purpose is to decrease the noise level of the chainsaw. A faulty muffler will cause an increase in noise level and a decrease in engine power. However, injury can occur if the operator accidentally touches extremely hot metal.

Scabbard

The scabbard is usually made of a hard durable plastic and is used to cover the guard bar and saw chain when the chainsaw is not in use. This will prevent injury when transporting and storing the chainsaw.

Chain

Yes, believe it or not, the saw chain is also a safety feature. Each chainsaw manufacturers produce specify chains for each chainsaw model they manufacturer. These chains have been geared to properly match the guide bar and chainsaw.

The best way to guarantee safety is to ensure that your saw chain is always properly sharpened. A key to sharpening is having the proper depth gauge setting. The depth gauge is a small steel protuberance that is in front of every cutting tooth. When the depth gauge is too low, the cutters will try to take too deep of a bite from the wood, thus increasing the chances of kickback. To increase safety, many saw chains also have what is known as guard links, which are in front of every cutter link. The guard link offer added limitations on the cutting depth.

In addition to these safety features, it is strongly suggested that every chainsaw owner take a chainsaw safety class. Many community colleges offer these one-day classes as well as many major home do-it-yourself stores.

In addition, when operating a chainsaw you should always wear the proper protective clothing, such as long pants, shirts, ear and eye protection, gloves, protective helmet, and steel-toed shoes.

The American OSHA Regulation 1910.266 mandates that employed chainsaw operators must wear the following Personal Protection Equipment:

1. Head Protection
2. Protection for the Face and Eye
3. Hearing Protection
4. Certified Chainsaw Protective Chaps or Pants that are UL listed (Underwriters Laboratories Incorporated)
5. Certified Chainsaw Protective steel toed Footwear

While these requirements are mandated for professional chainsaw operators who are experienced and professionals, it only makes since that the casual individual who operates their chainsaw seasonally should also use the same personal protective equipment.

Having worked disaster relief, I have lost count of the number of times that well-meaning individuals have ended up as victims during “cleanup,” simply because they did not use common sense and were not wearing the proper clothing when operating a chainsaw. Flip-flops, sandals, and tennis shoes will not protect your feet and legs when operating a chainsaw. Therefore, when you are purchasing your chainsaw, before you purchase all the wonderful accessories that will go with your new chainsaw, you should purchase protective clothing first. This should include a safety helmet, protective eyewear, earplugs, steel-toed no-slip boots, and protective gloves that are certified for use with a chainsaw, regular garden gloves and work gloves will not protect your hand if it happens to slip and encounter the saw chain while the chainsaw is running at full speed.

When using a chainsaw, you should always wear protective clothing, or as OSHA refers to it as Personal Protective Equipment or PPE.

Worldwide, there has been a general agreement as to what is suitable clothing that should be worn when operating a chainsaw. The following has been viewed as acceptable safety clothing:

Safety Helmet/ Hard Hat:

You’re favorite ball cap will not protect your head if you are struck by the force of the guard bar if kickback occurs. Your head protection gear should be strong enough to withstand the force of impact with the guide bar of the chainsaw, should a kickback occur. Therefore, you should wear hardhat that has been approved by OSHA for use with a chainsaw. The safety hard hat should also protect against small falling branches and limbs. According to OSHA, hard hats and safety helmets should be replaced immediately once they become cracked or discolored. It has been proven that when the chain brake has been disabled, a saw chain running at full throttle can cut through a hard hat.

Protective Eyewear:

Sunglasses are NOT acceptable protective eyewear. When operating a chainsaw you should wear safety visors, goggles, or eyeglasses that have side shields to protect your eyes from wood chips, sawdust, or twigs. However, many chainsaw operators in the logging industry prefer the use of conventional safety goggles in cooler weather and safety visor during hotter weather because the visor provides more ventilation.

Ear defenders/ Ear Plugs/ muffs:

Chainsaws are very loud pieces of equipment, which generate a noise level of approximately 115 decibels (dB). Therefore, to protect your hearing, you should wear a pair of ear defenders, earplugs, or muffs, which will ease the noise levels so that it will cause little to no damage to your hearing. Protective hearing-wear such as ear defenders, muffs and ear plugs should all have a decibel noise reduction rating, the higher the rating is the more protection that item provides. Several companies, which specialize in personal protective equipment often, offer complete sets that include hardhat, earmuffs, and protective eyewear usually at a very reasonable price.

Trousers/ chaps/ safety pants

Over the years, special fabrics have been developed for chainsaw clothing, and are still being improved upon and development even now. Conventional fabrics such as denim, provide little protection against a running chainsaw running at top speed from cut through to the user’s leg. The problem is creating a fabric that is lightweight so that the worker does not suffer from heat exhaustion and a fabric that is tough enough to withstand a chainsaw attack. Manufactures of chainsaws continue to chainsaws to the point that newer chainsaws can run at speeds of 45 to 55 miles per hour. Unfortunately, safety chaps, pants, and trousers do not provide a fail-safe, when working with a chainsaw, no safety gear does. What safety trousers, chaps, and pants do is increase the operator’s ability to sustain a chainsaw attack with minimal injury to the area where the chainsaw cuts occur.

OSHA does have guidelines for protective clothing for chainsaw operators. Safety chaps, leggings, pants, and trousers should cover the area from the groin area to approximately 2 inches above the ankles. Chaps and leggings must wrap around the leg and provide protection also to the calf area. Safety chaps, pants, and leggings are made from several layers of synthetic fabrics. The top layer is usually slippery and tough, with the goal that the chainsaw will skim over the fabric, instead of cutting through the fabric. The bottom or lower layer of fabric should be able to absorb the power of the chainsaw power. The third layer of defense, are long fibers of Kevlar. If the chainsaw cutting through the first layer of protective fabric, Kevlar threads will be pulled out by the running chainsaw, and into the chainsaw’s drive sprocket, where the Kevlar fibers jam the drive sprocket causing the chainsaw to stall. Once the Kevlar has been pulled into the chainsaw, the saw will have to be taken apart and cleaned out before it will function. These safety pants, leggings, and chaps meet the UL Classification and APA Class A standards plus all OSHA Logging Operations requirements.

Gloves

Because the majority of all chainsaw hand injuries occur to the back of the left hand, safety gloves specially designed for chainsaw use, the back of the left hand have the same strong cut-resistant fabric that safety pants, chaps and trousers do. When purchasing safety gloves, it is important that the gloves chosen are flexible, yet still provide protection. For those individuals who are left-handed, there are also specially designed safety gloves.

Protective Boots/ Footwear:

Protective chainsaw boots look similar to ordinary steel-toe boots, and have nonskid soles. However, they have several layers of the same protective fabric that is used on chainsaw pants, chaps and gloves on the exposed front surfaces of the boot. These boots have high tops and provide protection to your ankles in they accidentally come into contact with the moving chainsaw. Regular steel toe shoes only protect your feet from injury, which occurs from falling objects, but offer limited protection against accidental contact with a moving chain, therefore you should invest in chainsaw protective boots.

Additional Personal Protective Equipment

Whether you are cutting wood in the forest, or simply cutting wood in your backyard, in addition to wearing protective clothing, head gear, protective ear and eyewear, you should also have a first aid kit, cell phone or communication device of some sort. Your first aid kit must contain at least a large wound dressing.