Method for calculating Stud bolt lengths

The stud bolt theoretical length can be calculated by means of the formula:
L = 2 (s + n + h + rf) + g

• s = free threads (equals 1/3 time bolt diameter)
• n = nut thickness (equals nominal bolt diameter)
• h = flange thickness
• rf = height of raised face
  for class 150 and class 300 height of raised face is included in h height
• g = gasket thickness approximately 3 mm