What is SWL? How to find it?
The Safe Working Load (SWL) is the stress that a component of a lifting apparatus can safely bear in normal use.
The SWL of various apparatus, chains, ropes etc can be found out by using various formulas specific for ropes, chains, etc.
For ex: Formula SWL-Fibre Rope
(Diameter)²=SWL (Kg)
Example: For a 12mm diameter rope.
SWL=12*12=144Kg
Fomula Size-Steel wire rope
Square root of the load divided by 8
Example:5000kg load
Ø=√5000÷8
=√625
The diameter of steel wire rope=25mm
SWL=8D²
Hence, various items have a different SWL formula. There is no single formula to calculate the SWL of all ropes,chains, crane booms , etc.
The SWL of any item supplied on a vessel is provided in its certificate. Hence, to know the SWL of an apparatus, just look up its certificate or you can apply the relevant formula and calculate the SWL.