Chain Saw Safety
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Chain Saw Safety Overview
This program provides information regarding the safety requirements of chain saw use.
This program applies to employees who use chain saws while on the job. It does not apply to home use; however, the safety information provided certainly is beneficial to anyone using a chain saw regardless of location.
Departments that have personnel using chain saws must ensure that the equipment provided has the required safety features, personnel using the chain saws have received training on work practices, and are provided appropriate safety apparel.
Personnel using chain saws for work-related purposes must attend safety training and follow recommended practices described in this program. OSHA requires that appropriate personal protective equipment be provided by the employer and used by the employee.
Chain Saw Safety Online Program
Chain saws have many safety features, some of which are voluntary for the manufacturers to implement. If chain saws are used by employees, they must have these three safety features, and they must be in proper working order.
The chain brake stops the chain motion in the event that the operator falls onto the chain saw, or the chain pulls the bar into the tree being cut, reducing the potential for serious injury. It should stop the chain motion when pushed or pulled back towards the handle, and the chain motion should resume when the brake is reactivated.
The throttle and lock safety feature prevents accidental throttle engagement. Both the throttle and lock must be pressed in order for the chain to move.
The chain catcher is a small plastic or metal protrusion that prevents a broken chain from flying back towards the operator. If it is missing or broken, it must be replaced prior to use.
The impact from falling limbs and debris to the head is a major hazard when using chain saws to cut limbs or fell trees. ANSI-approved hard hats are required when operating a chain saw. Hard hats must be worn properly (i.e. brim forward) and maintained in accordance with the manufacturer's instructions. For more information, refer to the head protection section of the Personal Protective Equipment Program.
The impact from flying debris during cutting operations poses a hazard to the eyes and face. In addition to a metal-mesh face screen typically attached to the hard hat, ANSI-approved safety glasses (or goggles) are also required. For more information, refer to the eye and face protection section of the Personal Protective Equipment Program.
Although chain saws are designed to create the least amount of noise possible, there remains a risk of hearing loss from operating a chain saw due to the distance the saw can be held from the body, the amount and type of noise, and the duration of exposure. Appropriate hearing protection, such as ear muffs and/or earplugs, is required. For more information, refer to the hearing protection section of the Personal Protective Equipment Program.
The operator's legs are one of the most vulnerable areas of the body when using a chain saw. Leg protection, such as chaps or cut-resistant jeans, are required to be worn when cutting brush or trees on the ground. Cut-resistant chaps or pants are made of layers of material that are designed to jam the chain on the saw during contact. This will hopefully give the operator enough reaction time to prevent the saw from cutting into flesh. Chaps are not required to be worn when working in trees or cutting from an aerial lift.
- Chaps should extend from the waist to the top of the work boot in order to provide adequate coverage and protection.
- Leg chap straps should be kept as tight as possible to prevent them from being ripped away from the leg.
- Chaps must be kept clean in order to function properly. If they become dirty or matted, the chain saw can cut right through them. Follow manufacturer's instruction's closely for proper wash and care.
Heavy-duty foot protection is required when operating chain saws. Minimum requirements include leather work boots that extend above the ankle, are cut-resistant, and water-proof. Steel-toed boots are highly recommended for all chain saw use and are required when felling trees.
Leather work gloves will help maintain a good grip on the chain saw and prevent minor cuts and abrasions. Gloves with a padded palm will provide added protection again hand vibration and fatigue, which can result in numbness in the fingers or hand. For more information, refer to the hand and arm protection section of the Personal Protective Equipment Program.
Clothing should be tight-fitting to avoid entanglement with the chain saw. Shirt tails should be tucked in, sleeves should be buttoned at the cuff, and jackets and overalls should be snug and fastened.
Always follow the manufacturer's instructions for proper use and maintenance. The following tools may be necessary for proper maintenance.
- Bar wrench: To adjust the chain tension on the saw. The chain should be kept as tight as you can get it while still turning freely.
- Chain files: In the proper size to sharpen the cutters. The file tip will bend somewhat during use; however, the base of the file is made of case-hardened steel and can shatter or splinter when broken. Always carry the files in a safe place, such as a tool pouch. Never place them in your pockets (pants or overalls).
- Depth gauge: To assist with filing off the extra height on the "trailer" links of the chain. The gauge will help ensure that the height of the "cutter" is slightly higher than the "trailer" and thus allowing a better cut.
There are two basic types of chains on the market.
- Green label safety chains provide anti-kickback protection and are highly recommended.
- Yellow label chains do not provide anti-kickback protection. Use with caution.
The chain links should be inspected for excessive wear periodically. Many brands of chains will have a wear line on the heal of the cutter links to indicate if enough metal is still present between the rivet and the edge to hold the chain on the bar. Once the link is worn beyond the wear line, the chain must be replaced.
- It is not recommended that chains be repaired.
- It is not recommended that chains be shortened once they have been stretched beyond a safe limit.
Always follow the manufacturer's instructions for proper use and maintenence. Chain saws do not need to be drenched in oil. Pull the chain away from the bar and look for the presence of oil. If any oil is visible, it is enough - even though the top of the chain may appear dry. Most of the oil actually ends up going to the ground, which poses an environmental concern. The less oil you use, the less environmental impact created.
- Use only bar and chain oil, which is attracted to friction (motor oil is designed to move away from friction, and is not effective on chains).
- Biodegradable oil is acceptable, but may be more costly.
Chain bars are very sharp. Wear gloves when handling the bar to perform maintenance tasks. Chain bars wear from the inside (of the track) out. Dealerships can redress the bar at least twice, if necessary. As a rule of thumb, most bars will last through two chains before they need to be replaced due to excessive wear.
- Remove the chain and inspect the bar to make sure it is straight.
- Clean out the track of the chain bar.
- Turn the chain bar over every time you take the chain off. This ensures even wear and tear on the bar and chain. Note: If the chain saw seems to be cutting crooked, turning the bar over may help correct the problem.
Chain saws process a huge amount of air when in operation. Dirty filters make the engine work harder and can reduce the life of the chain saw. Therefore, air filters should be kept as clean as possible at all times.
- Remove the cover and shake the dust out of the filter.
- If it is recommended by the manufacturer, wash the filter with soap and water and allow it to air dry before reinstalling.
Reactive forces may occur any time the chain is rotating. They may result in loss of control of the chain saw, which may, in turn, result in serious injury or death. There are three common reactive forces at work when using a chain saw.
- Kickback may occur when the moving saw chain near the upper quadrant of the bar nose contacts a solid object, such as a nail, or becomes pinched by the tree being cut. The result is a rotational force in the direction opposite to the chain movement, meaning that the bar may be flung upward and backward towards the operator. Many factors influence the kickback reaction, including chain speed, the speed at which the bar and chain contact the object, the angle of the contact, and the condition of the chain.
- Pushback occurs when the chain on the top of the bar is suddenly stopped when it becomes pinched by the tree, caught, or encounters a foreign object in the wood. The resulting force drives the saw straight back toward the operator and may cause loss of saw control. Pushback typically occurs when the top of the bar is used for cutting.
- Pull-in occurs when the chain on the bottom of the bar is suddenly stopped when it becomes pinched, caught, or encounters a foreign object in the wood. The reaction of the chain pulls the saw forward and may cause the operator to fall onto the chain saw or lose control of the saw. Pull-in frequently occurs when the bumper spike of the saw is not held securely against the tree or limb, and when the chain is not rotating at full speed before it contacts the wood.
How you hold the chain saw is very important - if you are in the "line of fire" of the chain, you are in danger. If you're holding the chain saw (during operation) so that you're looking down the chain, it's about the same thing as looking down the barrel of a loaded shotgun.
- Your body should be positioned to the left side of the chain saw at all times during operation.
- Your right hand should be on the throttle, and your left hand should be holding the guide bar. Unfortunately, there is no such thing as a left-handed chain saw. Left-handed persons should hold the chain saw in the same manner as a right-handed person would hold it.
- Your body should be in such a position that you have control over your balance.
- Avoid leaning over the chain saw when operating.
- Avoid holding the chain saw above your shoulders when operating.
- Do not operate a chain saw from a ladder.
- Make sure you have a good, solid footing at all times. If you slip or trip, you will most likely fall onto the chain saw. Avoid muddy areas and other slippery surfaces. If necessary, remove debris from the area where you will be working.
The saw should be held to your side. The chain bar should be pointed behind you and the chain brake should be engaged. Do not hold it in front and engage the throttle while carrying.
Before starting the chain saw, the chain brake should always be engaged. The area should be free of debris, and the starter grip should be pulled with the right hand. There are two approved methods for starting the chain saw. The preferred method is while the chain saw is on the ground. This provides maximum control and minimal opportunity for accidents. The second method is where the chain saw is otherwise supported (i.e. hold the rear handle of the chain saw tightly between your legs just above the knees). "Drop starting" a chain saw is dangerous and should never be done.
Always follow the manufacturer's instructions for proper fueling. Chain saws should be fueled in an area that is at least 10 feet away from any open flame or ignition source, and as always, never fuel a chain saw while it is running.
One important factor is the gasoline (fuel) being used. The octane is not as important as the freshness of the gasoline. Fresh gasoline (mixed to the recommended gas to oil ratio of 50:1) cools the two-cycle engine more effectively than old gasoline. Gasoline goes "bad" in about 90 days, much the same as a bottle of soft drink loses its fizz after a few days.
- Gas stabilizers or boosters are not necessary for two-cycle engines.
- Once a plastic gas can begins to fade in color, the polymer is dissolving into gasoline, which can affect the engine.
Carburetor icing can occur when the chain saw is operated in temperatures below 40 degrees Farenheit. Erratic engine performance is a typical indication that the carburetor has frozen, such as "choking" when in use (because it's frozen) and operating fine when it is checked later (because it has thawed).
Many chain saw brands have a gate/plate/plug with a snowflake and sun on it that can be reversed in cold weather to recycle exhaust (warm) air back through the system to prevent freezing or icing. In warmer weather, the gate/plate/ should be turned over to help cool the engine, or the plug pulled/pushed as indicated. Often this device is found near the air filter and the cover must be removed to access it. Always follow the manufacturer's instructions for proper use and maintenance.
It is important to have a plan before you begin cutting. Which way do you anticipate the tree falling and what will be your primary and secondary escape routes - typically 45 degrees to either side of the tree. Check the area for objects that may be affected by the falling tree - overhead power lines, vehicles parked nearby, or houses or other structures in the area. Make an educated guess as to how far the tree will fall and ensure the area is clear.
Metal splitter wedges are for splitting firewood with an axe - not for assisting with tree felling. If the chain saw hits the metal wedge, it could result in a reactive force as well as damage to the saw. Always use a plastic felling wedge with the chain saw.
Always consult your operator's manual for tree felling techniques. Descriptions and illustrations are often provided which can help you decide the proper method and technique for what you will be cutting. There are two situations that pose a significant risk and are worth mentioning here.
- "Spring poles" are present when a tree is bent over like a catapult and will spring loose if not properly cut. Make several small cuts (not completely through the tree) in the arch of the tree. This should ease the tension and permit you to safely cut the tree.
- "Widow-makers" refers to logs and fallen limbs that are stuck up in a tree that you're about to cut down. They are unpredictable, uncontrollable, and dangerous. Whenever possible, remove the limbs before cutting the tree/limb to minimize potential accidents.
Chain Saw Safety Frequently Asked Questions
No, they are not required, but they are highly recommended. Departments owning chain saws or who have personnel using chain saws are encouraged to provide any additional safety features, where possible.
Regardless of who owns the equipment or tools used by an employee while on the job, it must be in good condition and in proper working order. Good condition would also include any required safety features of the equipment/tool. Departments permitting employee-owned equipment/tools to be used while on the job are responsible for ensuring it is safe. If the person is injured while on the job because of defective, improper, or sub-standard equipment, it is still work-related. It is our goal, and everyone's obligation, to reduce hazardous conditions in the workplace.
It should not be used. Report it to your supervisor for replacement, repair, or retrofitting. Chain saws without the required safety features can be dangerous if used.
Robin McCall-Miller, Occupational Safety Program Manager