Bending radius R of the pipe bend, this bend is a radius of curvature corresponding to the center line. Multiple diameters generally OK. Such as: Hot elbow bend is usually one to two times, and the fire simmer elbow bend is usually three to four times, so the magnification used for low pressure pipeline bend. High pressure steam pipe bending radius plant according to drawings to determine the general bent of six to ten times. Commonly asked their length pipe elbow 30 degrees 45 degrees 90 degrees formula to calculate what it 1.5D. 2D. 4D. 5D's elbow-length algorithm? Please also expert advice. Thank you to answer one said 1.5D. 2D. 4D. 5D refers to the bending radius. 2, a simple calculation of the length of the top of the bend radius used (that is, when a fire simmer crater length): 90 degrees bend radius is multiplied by 1.57; 45-degree bend radius is multiplied by 0.785; 30-degree bend radius is multiplied by 0.523.