FALL ARREST CONSIDERATIONS
In all cases when working at height using fall arrest type equipment it is essential that there be adequate clearance under the area of work so that in the event of a fall the user will not strike the ground or any other hazardous objects during the fall. If it is assessed that the occurrence of a fall would endanger the user then other alternatives of fall protection systems must be considered.This may include the use of shorter shock absorbing lanyards, retracting lanyards, relocating anchor point or adjustable lanyards. In each case the fall clearance must be identified and the hazards associated with fall clearance eliminated.
The benefits of reducing free fall distances are multiple. If the free fall distance is reduced then the load on the system and the person are reduced, also the recovery method may be simplified and time may be significantly reduced.
Wherever possible the attachment point for a fall arrest system should be located above the attachment point on the users harness. When this is not possible the shock absorbing lanyard length must be reduced to ensure that the maximum fall distance of the user is limited to 2m (Consult AS/ NZS1891.4 cl 8.1). A user should never climb above the attachment point using a fall arrest shock absorbing lanyard as this only adds to the free fall distance which may take it over the permitted 2m.
SHOCK ABSORBING LANYARDS INERTIA REELS – FALL CLEARANCES
Fall Clearances Shock Absorbing Lanyards.
Fall Clearances Inertia Reels.
FC = FT + 1000 FC = Foot Clearance FT = Fall Total
FC = FF + AB + 1000 FC = Foot Clearance FF = Free Fall (Maximum allowed 2000mm before activation) Add 250mm for Harness slippage. AB = Shock Absorber Extension AS/NZS1891.4 Advises that this can be estimated using FF which reduces FC accordingly.
(Free Fall, Activation and Declaration to be 1.4m max) Add 250mm Harness slippage.
AS/NZS1891.4:2009 advises that this can be estimated at 700mm + stretch and slide.
1000mm standard safety clearance figure.
FF
AB
600mm 1000mm 1500mm 2000mm
300mm 500mm 600mm 900mm
1000mm standard safety clearance figure.
B-SAFE CATALOGUE
9
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