Zenoah GZ3500T General requirements working at height, Preparing to use the saw in the tree, GB-6

GZ3500T

WORKING WITH TREE SERVICE CHAIN-SAWS FROM A ROPE AND HARNESS

This chapter sets out working practices to reduce the risk of injury from tree service chainsaws when working at height from a rope and harness. While it may form the basis of guidance and training literature, it should not be regarded as a substitute for formal training.

General requirements working at height

Operators of tree service chainsaws working at height from a rope and harness should never work alone. A competent ground worker trained in appropriate emer- gency procedures should assist them.

Operators of tree service chainsaws for this work should be trained in general safe climbing and work position- ing techniques and shall properly equipped with har- nesses, ropes, strops, karabiners and other equipment for maintaining secure and safe working positions for both themselves and the saw.

Preparing to use the saw in the tree

The chainsaw should checked, fuelled, started and warmed up by the ground worker before it is sent up to the operator in the tree. The chainsaw should be fitted with a suitable strop for attaching to the operator’s har- ness:

a)choke the strop around the attachment point on the rear of the saw (A);

(A)

b)provide suitable karabiners to allow indirect (i.e. via the strop) and direct attachment (i.e. at the attach- ment point on the saw) of saw to the operators har- ness;

c)ensure the saw is securely attached when it is being sent up to the operator;

d)ensure the saw it secured to the harness before it is disconnected from the means of ascent.

The saw should only be attached to the recommended attachment points on the harness. These may be at mid-point (front or rear) or at the sides. Where possible attaching the saw to centre rear mid-point will keep it clear of climbing lines and support its weight centrally down the operator’s spine.

When moving the saw from any attachment point to an- other, operators should ensure it is secured in the new position before releasing it from the previous attachment point.

Using the chainsaw in the tree

An analysis of accidents with these saws during tree service operations shows the primary cause as being inappropriate one-handed use of the saw. In the vast majority of accidents, operators fail to adopt a secure work position witch allows them to hold both handles of the saw. This results in an increased risk of injury due to:

•not having a firm grip on the saw if it kicks back;

•a lack of control of the saw such that it is more liable to contact climbing lines and operators body (par- ticularly the left hand and arm)

•losing control from insecure work position resulting in contact with the saw (unexpected movement dur- ing operation of the saw)

Securing the work position for two-handed use

To allow the operator to hold the saw with both hands, they should as general rule, aim for secure work posi- tion where they are operating the saw at:

•hip level when cutting horizontal sections;

•solar plexus level when cutting vertical sections.

Where the operator is working close into vertical stems with a low lateral forces on their work position, then a good footing may be all that is needed to maintain a secure work position. However as operators move away from the stem, they will need to take steps to remove or counteract the increasing lateral forces by, for example, a re-direct of the main line via a supplementary anchor point or using an adjustable strop direct from the har- ness to a supplementary anchor point.

GB-6