This International Standard specifies requirements and test methods for the relative level of heat resistance of conveyor belt covers made of rubber. It gives the permissible variations of hardness, elongation at break and tensile strength after exposure to heat. It is applicable only to those conveyor belts having a cover thickness greater than or equal to 4 mm. It is not suitable or valid for light conveyor belts as described in ISO 21183-1.^[1]