Safety guidelines for felling trees with chainsaws
Chainsaw felling of trees is recognized as one of the more dangerous activities in forestry. However the risks can be reduced considerably with well trained and professional operators. WorkSafeBC and the BC Forest Safety Council have produced a training standard that will go some way in achieving these risk reductions. The document begins by providing an initial safety meeting checklist and universal principles for safe felling. The standard then proceeds to discuss various safety aspects under the following headings:
- Working safely: This considers general safety aspects such as safety programmers.
- Clothing and personal equipment: The various safety clothing that should be worn is covered.
- Safety equipment and personal wellbeing: This section includes information on aspects such as operator visibility and climatic factors.
- Stretches: Various exercises that should be performed by operators are described.
- Chainsaw and other equipment: This includes choosing a chainsaw, carrying a chainsaw by hand and chainsaw refuelling.
- Chainsaw maintenance and filing: A chainsaw maintenance checklist is provided, along with safe chain filing information.
- Safe chainsaw handling procedures: Various safety aspects are covered, with a focus on kickbacks.
- Axes and wedges: The uses of axes and wedges with chainsaw felling are described.
- Planning and safety meetings: Various plans, meetings, checks and procedures are discussed.
- Falling areas and active falling areas: The safe working procedures are described for entering a falling area and barricading a falling area.
- Crew transport and first aid coverage: Transportation of the crew, tools, fuel and equipment is discussed.
- Tree species group hazards: The risks associated with felling various tree species is described.
- Dangerous tree indicators: The aspects of a tree that create safety hazards are explained.
- Various cutting procedures: These include different types of undercuts, directional control and wedging.
Other aspects covered include managing risk factors, escape routes, opening the falling face, site-tree assessments, inadequate felling cuts, correcting incomplete felling cuts, and steep slope, upslope and riparian felling.
The helmet offers some protection for the user’s head against impact by the cutter bar of the chainsaw should a ‘kickback’ occur. Kickback is when the running chainsaw jumps up unexpectedly out of the cut, thus endangering the saw operator. Helmet protection can only be successful if the chain brake has been operated to stop the saw chain, since a chain running at full speed can easily cut into the helmet. The helmet, and its eye protection guard, also protect against impacts from small falling or flying objects, such as dead twigs and branches from a tree being felled.
Exposure to the sun causes the plastic of the helmet to weaken over time, so it is recommended that a helmet is replaced every 3–5 years. A helmet normally has a symbol inside that shows when it was made. Many helmets also now have a sticker on the outside that fades with exposure to light. When the sticker has faded the helmet should be replaced. Another way of determining if a helmet needs to be changed is to press the two sides of the helmet towards each other. If a cracking noise is heard, the helmet must be replaced.
Visor or goggles
The relatively flimsy mesh visor, with imperfect coverage of the face, is considered acceptable because the chips produced by well-maintained chainsaws are of relatively uniform size and speed. Unlike other woodworking tools, a chainsaw with a sharp chain produces little or no sawdust, only chips (that are too large to fit through the visor’s mesh).
Some chainsaw users prefer conventional safety glasses or goggles. The choice may depend on the environment. The visor provides better ventilation for hard work in hot weather. Often, both safety goggles and a visor are employed for superior protection.
Chainsaw safety mitt
A leather mitt for the operator’s left hand that is fitted to (but is free to rotate on) the front bar of the chainsaw.
The safety mitt ensures that if kickback occurs the operator’s hand remains on the bar of the chainsaw. This means that the kickback is more easily controlled and the chain brake is more easily engaged. The safety mitt also protects the operator’s left hand in the same way as chainsaw safety gloves. The protection on the left hand mitt protects when the chain derails and jumps over the front handle.
Most safety mitts have a protection class 0 (up to 16 m/s chain speed, see below). There are mitts available covering class 1 (20 m/s chain speed).
Ear defenders and ear plugs attenuate noise to levels that cause little or no damage to the user’s hearing. Non-electric chainsaws are very loud, typically 115 dB, above the recommended exposure limit of 85 dB from the National Institute for Occupational Safety and Health.
In the EU, ear defenders must comply with EN352-1.
Special fabrics have been developed for chainsaw clothing, and this development is still ongoing. Conventional fabric is useless as protection against a running chainsaw, as the fabric is cut through immediately.
There is a real struggle and conflict between making a fabric proof against more violent impact, and making it light, flexible and comfortable enough for the user. Clothes which make the user too hot, or which prevent the user moving easily, are a safety problem in themselves. A worker unable to move easily and/or suffering from being too hot is not safe. Extra fabric layers are added to clothing to improve cut resistance, but clothes which cannot be cut at all by a powerful saw are impractical, even with modern fibres. Additionally saw and chain technology seems to be outstripping fabric technology. It is almost impossible to protect against high power saws employing aggressive cutting chains.
A classification scheme has been developed in the EU to rate trousers, and fabric in general, for protection against cutting.