Requirements for pulley blocks to lift up to 6 tons in combination with natural and synthetic fibre ropes of maximum safe working load up to 10 kN on the single part, rope safety factor 8, maximum rope velocity 0.5 m/s, and a sheave diameter at the bottom of the groove not less than five rope diameters. Materials and heat treatment, block shell, head fitting, becket, axle pins, sheaves, lubrication, locking nuts, finish. Recommendations for contracts and marking of safe working load per rope fall.Cross References: BS 350*BS 919*BS 970*BS 1452*BS 1486*BS 1610*BS 1839*BS 1936*BS 2052*BS 2789*BS 2902*BS 3032*BS 3100 *BS 3758*BS 3912*BS 3977*BS 4018*PD 5686*