Demonstrated knowledge required to complete the tasks outlined in elements and performance criteria of this unit:
- organisational procedures for safety and serviceability checks
- how the following factors affect selection of descent and ascent routes for natural surfaces including:
- season of operation, weather and environmental conditions
- participant characteristics including age, size, weight, fitness and abseiling skill level
- group objectives and size
- environmental hazards specific to abseiling on natural surfaces and how these affect:
- safe access to and egress from the pitch
- choice of descent and ascent routes for safety of abseiler
- positioning of top or bottom belay systems for safety of belayer
- features, functions, advantages and disadvantages of different types of anchors used for abseiling on natural surfaces including:
- fixed artificial:
- threads
- bolts
- chains
- concrete bollards
- naturally occurring:
- artificial removable:
- spring loaded camming devices
- nuts, wires and hexes
- pitons
- issues that are assessed when selecting anchors and likely impacts of poor condition on performance under load:
- wear and abrasion due to age and use
- corrosion
- decay
- dislodgment
- underlying stability of structural features and presence of:
- cracks
- deformities
- fissures
- meaning of the following terms, and principles which apply when rigging anchors and ropes:
- equalisation of load
- single point of failure
- anchor redundancy
- angle of separation
- shock loading
- cross loading and cyclical loading of carabiners
- mis-alignment of carabiners
- closing the system, including advantages, disadvantages and methods used
- types of forces (upwards, downwards) generated during abseiling and belaying, and how to calculate load on anchors and ropes for these circumstances:
- top rope top belay
- bottom brake belay
- self-belay
- abseiler descending under control
- abseiler fall
- belayer arresting falls
- the effects of rope stretch during operations and implications if not minimised:
- abrasions
- rope bounce
- undue stress on the anchor system
- potential for abseiler to impact with hazards, or become entangled
- features, functions, advantages and disadvantages of the following abseiling and belay equipment used on natural surfaces:
- abseiling and belay systems for:
- single rope
- releasable abseil line
- rope systems suitable for single rope techniques
- top rope top belay
- bottom brake belay
- self-belay
- descending devices:
- assisted locking
- inline
- plate
- figure 8
- tubular
- improvised
- belay devices:
- assisted locking
- inline
- plate
- figure 8
- tubular
- improvised
- carabiners
- harnesses of different types
- static and dynamic rope and when each might be used
- rope protectors
- tape
- sewn sling
- Prusik cord
- how the following factors affect the selection and rigging of above equipment:
- site characteristics including position of rub points
- weather and environmental conditions
- participant size, weight, and abseiling ability
- cumulative load for group size and number of abseils
- abseiling techniques to be used
- distance, height and angle of anchor relative to top edge of abseil
- manufacturers' specifications for equipment use
- techniques used to establish belay systems for safety of belayer:
- rigging belays for performance of rescues
- attaching to anchor or self belay safety system
- situations requiring back up belay systems
- when different knots are used, advantages and disadvantages, and how to tie them:
- fixed eye
- mid line tied in the bight
- end to end joining
- termination
- load control hitches
- slide and grip hitches
- types of safety checks completed for rigging of equipment
- how to care for abseiling equipment when rigging to avoid damage, and promote long lifespan
- potential environmental impacts of rigging for abseils on natural surfaces including cliff faces and techniques used to minimise damage.