Oil-based coating or bitumen enamel is used for external surface coating of steel pipes to protect against corrosion. This coating is one of the oldest pipe coatings that are applied in factories on the external surface of steel pipes according to the needs of customers and according to BS4147, EN10300 standards. The most important feature of petroleum-based bitumen coating is its corrosion resistance and economic efficiency.The corrosion intensity of the soil around the pipe has no effect on the bitumen enamel and this coating is resistant to acids, bases and salts. The steps of applying bitumen enamel coating on the outer surface of steel pipes are as follows. 1. Cleaning the pipe surface 2. Shot blasting the external surface of the pipe 3. Spraying synthetic primer on the pipe 4. Application of petroleum-based bitumen 5. Inner wrap tape cover 6. Application of petroleum-based bitumen 7. Covering the outer tape or outer wrap Depending on the required thickness and strength, one layer (single coat) or two layers (double coat) of the tape is used. The single coat has a thickness of 4 mm and the double coat has a thickness of 5.5-6 mm.