|Disaster Rescue - Australian Emergency Manual (Natural Disaster Organization, 183 p.)|
|CHAPTER TEN - RESCUE FROM HEIGHTS AND DEPTHS|
10.18 The jib consists of a pole projecting about one metre (horizontal distance) out from a structure, with a snatch block attached to the end, through which is reeved a lowering rope. It is a quick method of lowering stretchers in a horizontal position. The material used for the jib must be strong enough to allow the one metre projection to bear all weight.
Before pushing the jib pole out, the snatch block must be secured. To do this, 'middle' a 12mm rope and Clove Hitch the middle of the lashing to the hook of the block. Then cross the two running ends over the top of the pole about 300mm back from the end. Take two or three cross-over turns around the pole and through the hook, then frap the centre of the lashing, again using the cross-over turns and finish off. Reeve the lowering rope and tie a Thumb knot 2m back from the running end to prevent the rope running back through the block. (Figure 10:19)
Alternatively, a nylon tape sling can be passed several times around the pole about 300mm from its end. The block should be secured to both ends of the sling with a screwgate karabiner, and the hook securely moused.
NOTE: Ensure the lowering rope is reeved through the block, so that the running end goes directly from the block to the lowering party, and the standing part is led to the casualty by the same way the casualty will leave the structure.
The pole must then be firmly lashed in position, making sure that the snatch block is in the centre of the opening and about 1m out from the wall. It is important that the pole be lashed as near as possible to the point where it passes over the wall, as side strains will often be set up during the lowering operation. The other end of the pole must be secured. Remember this end of the pole will tend to lift and this must be borne in mind when selecting an anchorage. It is not necessary that the pole should be at right angles to the wall or that it should be in the horizontal plane, eg. the inside end of the pole could be anchored down to a floor joist, if it were solid.
The casualty is blanketed and lashed in the usual way and a Chair knot or four-point bridle connected. Two guide lines are attached to the stretcher and passed down to the rescuers on the ground. The lifting rope is secured to the Chair knot or four-point bridle.
At least two, preferably three, rescuers will be required on the lowering rope. When all is ready, the weight is taken on the lowering rope and the two rescuers up top ease the casualty out through the opening, feet first. As soon as possible the rescuers on the guide lines swing the stretcher around parallel to the wall and lowering commences. If necessary, the guide line rescuers can pull the stretcher out to a clear landing space as it comes down. They should walk in on their lines so as to be ready to take hold of the stretcher as it comes in reach.
The jib can also be used successfully for rescues using mechanical descenders.