
The slip on flange has a low hub
The slip on flange has a low hub and slips onto the pipe prior to welding. Welding is carried out on the inside and outside to provide sufficient strength and prevent leakage. Slips on flanges are all bored slightly larger than the OD of the matching pipe to allow for the welds to hold. They are many times preferred over weld necks due to their lower cost, though net installation cost is often the same due to the additional welding.