(a) Each mechanical fitting used to make a hot tap must be designed for at least the operating pressure of the pipeline.
(b) Where a ductile iron pipe is tapped, the extent of full-thread engagement and the need for the use of outside-sealing service connections, tapping saddles, or other fixtures must be determined by service conditions.
(c) Where the diameter of a threaded tap in cast iron or ductile iron pipe exceeds 25 percent of the nominal diameter of the pipe, the pipe must be reinforced, except that a 1ΒΌ-inch (32 millimeters) tap may be made in a four-inch (102 millimeters) cast iron or ductile iron pipe, without reinforcement. In cast iron pipe of a nominal diameter of six inches (152 millimeters) or less, all threaded taps for service line connections must be reinforced.