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Swl The safe working load (SWL) of a lifting appliance is the maximum mass which may be lifted vertically by this appliance

Proof Load
It is the excessive load applied on lifting appliance during testing, without exceeding its elastic limit, in presence of competent authority.
MSL stands for maximum securing load. It is a term used to define the allowable load capacity for a device used to secure cargo to a ship. SWL is the safe working load and may be substituted for MSL for securing purposes, provided this is equal to or exceeds the strength defined by MSL.

How to carry out Load test ? he wanted to know the weight allowance for SWL….

1. In the case of cranes, the test load is to be hoisted, slewed and luffed at slow speed. Gantry and travelling cranes together with their trolleys, where appropriate, are to be traversed and travelled over the full length of their track.
2. In the case of variable load-radius cranes, the tests are generally to be carried out with the appropriate test load at maximum, minimum and at an intermediate radius.
3. In the case of hydraulic cranes where limitations of pressure make it impossible to lift a test load 25% in excess of the safe working load, it will be sufficient to lift the greatest possible load, but in general this should not be less than 10% in excess of the safe working load.
4. As a general rule, tests should be carried out using test loads, and no exception should be allowed in the case of initial tests. In the case of repairs, replacement or when the periodic examination calls for re-test, consideration may be given to the use of spring or hydraulic balances provided the SWL of the lifting appliance does not exceed 15 tonnes. Where a spring or hydraulic balance is used it shall be calibrated and accurate to within ±2% and the indicator should remain constant for five minutes.
5. If test weights are not used this is to be indicated in column (3) of Certificate of Test and Thorough Examination of Lifting Appliances.

SWL Proof load
Up to 20 tonnes 25% Excess of SWL
Exceeding 20 tonnes but not exceeding 50 tonnes 5 tonnes Excess of SWL
Over 50 tonnes 10% Excess of SWL

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