This International Standard establishes a method of calculating minimum pulley diameters for conveyor belts. It applies to belts made of rubber or plastics with textile or metal carcasses, of different carcass thickness and different carcass materials, operating at any anticipated belt tension up to, but not exceeding, the maximum belt tension (RMBT). It does not apply either to belts which have a carcass thickness of more than 20 mm or to those which have intermediate layers of rubber or plastics of more than 0,8 mm thickness between the plies. Nor does it apply either to heat-resistant belts on conveyors for hot products at temperatures over 100 °C or to belts in service at ambient temperatures under -40 °C. The use on conveyor belts of pulleys with diameters too small for the carcass construction may lead to premature belt failure. NOTES 1 The values indicated in this International Standard are minimum values to be used in the absence of information provided by the conveyor belt manufacturer. 2 The calculation of the minimum pulley diameter according to this International Standard is valid for all general applications. For special purposes, the conveyor belt manufacturer may allow smaller pulley diameters. For belts which are not listed in the following tables, consult the manufacturer. 3 In the case of use of pulleys with diameters larger than those corresponding to the minimum diameter calculated for the recommended maximum belt tension, an increase of this maximum tension is not permissible.