Identified Flying Objects (IFO)

One of the greatest fears when using a chainsaw is being cut by its spinning chain but for the groundcrew the chainsaw can become a lethal missile when dropped from a tree.

How many climbing arborists that are reading this article have had a chainsaw drop from their harness once or more during their career? How many ground crew members have seen a chainsaw hit the ground or even had a near miss? I have already heard some very graphic near misses, perhaps you have some more.

In my travels I have seen some amazing saw lanyards or saw strops. Anything from a length of chainsaw starter cord, a dog leash and even a fashioned coat hanger.

In general, all equipment used at height when working from a harness should be attached by a strop. If that equipment is too heavy to carry on a climbers harness then it should be suspended from a separate rope. The code of practice for the Amenity Tree Industry states that chainsaws should be attached to the climbers harness by a tool strop. The tool strop should be long enough to allow the chainsaw to hang below the climbers feet. This may be common sense and a standard work practice for you but some climbers still choose not to use a tool strop but to hang the saw on an open hook from their harness or on branch stubs when not in use.

The use of hooks is not a problem when used in conjunction with a tool strop. The use of a saw hook to hang the saw at waist level has some advantages and disadvantages. Some of these are listed below:

Advantages

• Damage to the chainsaw is reduced when swinging from branch to branch or tree to tree.
• The chainsaw travels with you through forks and over branches as opposed to needing to lift it over branches all the time.

• The saw is not hanging below you and hitting structures when working near roof tops or television antennas.

• The saw is not being dragged on the ground when leaving or returning to the ground.

Disadvantages

• The chainsaw catches on foliage and branches in some trees because you are less streamlined.
• The muffler can contact with skin or clothing causing burning. Also the chain hangs very close to your leg leading to cuts. (Important: never leave the chainsaw running when hanging on the hook).

• The hook catches on everything when climbing in some trees especially on vine covered trees.

• During an uncontrolled swing or fall the chainsaw can cause injury. This is less likely to occur when the saw hangs below your feet.

In my option, the saw hook serves a useful purpose in some cases depending on the type of job, the frequency of chainsaw use and the size of the chainsaw being used. Using just a saw strop can be limiting at times, be adaptable both methods have their good and bad points. See figure two - a ladder hook.

Note: the hook can be either open or with a gate. It doesn’t matter as long as you use a tool strop on the chainsaw.

The saw strop comes in many forms. This is largely due to the lack of a purpose made product. Also, like harnesses, climber have their own views on the best type of chainsaw strop assemble. Approximately 80% of saw strops I have seen have problems which will lead to early failure or accidental release from the harness.

The attachment hardware on the chainsaw strop is the critical link. Most chainsaws that crash to the ground are related to hardware failure or detachment for the harness. I have seen the use of non-locking karabiners, sailing snap hooks and clips used for dog leads and saddlery. Most of these, if not all, are inappropriate especially when using larger chainsaws. The failure of these light weight hooks or the hook lending itself to easy roll-out is very high. Ground crews are placed at risk when working in the drop zone, so it is not worth the risk of using inadequate equipment. The attachment hardware should be at least double action and auto locking. This may be a karabiner or a snap hook. If using a karabiner choose one that has a closed eye or a keeper to prevent the karabiner rotating on the strop. See figure one

Closed eye karabiner ladder hook

The saw strop should also be easy to hold and grip with one hand. These features will not be found in the above mentioned starter cord or the coat hanger versions.

The code of practice for the amenity tree industry also recommends the use of a “weak link” be incorporated within the chainsaw strop. The weak link is a safety feature intended to fail should the chainsaw be overloaded due to the saw jamming in a cut section of a log or branch.

The weak link is nothing new but it has been formalised to be included in the saw strop and not the harness accessory dee rings. It seems that the weak links build into some arborist harnesses have been failing regardless of overloading and that a weak link on a harness can be dangerous should the climber accidentally clip into it for support. The problem is there is not yet a saw strop on the market with a built in weak link that I am aware of.

The question may be at what force should the weak link fail and will the weak link deteriorate during normal use to the point of failure. The force required to break the weak link must exceed the heaviest chainsaw used and be multiplied by the maximum fall factor possible, that is a fall factor of two (twice the saw strops length). Also, when this figure is calculated, is the force too great for the human body.

It’s amazing that something so simple as a saw strop can raise so many issues relating to safety. The make shift methods of the past will be just that and the industry will move on, as it should, to a much safer and more professional occupation. In this day and age I would like to think that all climbing arborists are using a saw strop of some form. This article may, I hope, make you think about the current design of your saw strop and that any step forward is an improvement. The safety of your crew may depend on it.

Next: Practical Hazard Assessment