Safe work load calculation of hoisting wire rope and hoist chains

Hoisting wire rope and hoist chains are the important part of the hoist which are closely bound up with the safe work load, now let’s talk about the formula or rule of thumb to calculate the SWL of ropes and hoist chains. Basic: All diameters are measured in millimeters (mm). All weight are calculated in Kilograms(kg). Formula SWL-Fiber Rope Diameter in mm squared=The weight in kg. (Diameter)²=SWL Kg Example: For a 12mm diameter rope..... SWL=12*12=144Kg Formula Size-Fiber Rope Choosing the correct rope for the load Fiber Rope Square root of weight Example:900Kg load Rope diameter=√90=30mm Hoisting wire rope Construction 6*19 (6 strands*19 wires) 6*24 (6 strands*24 wires) 6*37 (6 strands*37 wires) Electric hoisting wire rope drawing Formula SWL-Steel Hoisting wire rope SWL=8D² 8 times stronger than Fiber (Diameter)²*8=SWL Kg Example: For a steel Hoisting wire rope of 15mm diameter SWL=15*15*8=1800Kg Formula Size-Steel Hoisting wire rope Square root of the load divide by 8 Example:5000kg load Ø=√5000÷8 =√625 The diameter of steel Hoisting wire rope=25mm SWL=8D² Steel Hoisting wire rope discarding factor 10% of the wires broken in a length of eight times the diameter Example:6*19 construction 20mm Diameter 6*19=114 wires 10% of 114 wires=11 8*20mm=160mm 11 wires broken over a length of 160mm discard sling Electric hoisting wire rope drawing Formula SWL-Hoist chains grade 30 Nine times stronger than Fibre (Diameter)²*9=SWL (Kg) Contoh: Garispusat=18mm SWL=18*18*9 =2916Kg SWL=9D² Formula SWL-Rantai Gred Peblagai Grade 30 hoist chains=9 times stronger than fiber rope Grade 40 hoist chains=12 times stronger than fiber rope Grade 60 hoist chains=18 times stronger than fiber rope Grade 80 hoist chains=24 times stronger than fiber rope Formula for different grades 0.3*diameter²MM*Grade of Hoist chains Or SWL=0.3*D²*Grade Formula Size-Hoist chains of different grade Square root of the weight (Kg) divide by the grade of China Example: Weight=5400Kg & Grade=40 Diameter of Hoist chains=√Weight÷(0.3*Grade) =√5400÷(0.3*40) =21.2 mm W=12D² Load factor 2 slings at an angle Sling angle 30° 60° 90° Load factor 1.93 1.73 1.41 Comparative Methods of Wire Rope Slinging Full Wrap Hoisting wire rope safe working load drawing