+++guide-for-doggers-ODLICNO

Loading factors and slinging
In the examples below all the angle and reeve factors are for FSWR. The arithmetic is set out so that
calculations can be easily worked out on a calculator.
1
To calculate the maximum weight of load that can be lifted, multiply the SWL of the sling (s) by the
angle factor and by the reeve factor.
Formula:
Max load = SWL (of sling) x angle factor x reeve factor
For example: The SWL of each leg of a two-legged sling is 8 tonnes, the angle between the two
sling legs is 60 degrees and they are reeved around a square load.
This means a factor of 1.73 for the angle and another factor of 0.5 for the reeve.
Sling SWL 8 tonne
Angle factor 1.73
Reeve factor 0.5
Therefore:
Max load = 8 x 1.73 x 0.5
= 6.92 tonnes
6.92 tonnes is the maximum weight that can be lifted.
2
To calculate the SWL of multi-leg slings needed to lift a load, divide the weight of the load by the
angle factor.
Formula for a calculator:
SWL = weight ÷ angle factor
Formula can be written:
SWL = weight
angle factor
For example: The weight of the load to be lifted is 20 tonnes and the angle between the legs of a
two-legged sling is 60 degrees. This means that the load factor is 1.73 for the angle.
Weight 20 tonnes
Angle factor 1.73
Therefore:
SWL = 20 ÷ 1.73
= 11.56 tonnes
Therefore, use a sling with a lifting
capacity greater than 11.56 tonnes.
Workplace Health and Safety Queensland (Department of Justice and Attorney-General)
Information guide - Guide for doggers
PN10123 Last updated 15 July 2010
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