A pipe coupling method includes an inlet insert, a clamping ring, a clamp and the forming of a flange on an end of two adjacent pipes. A clamping ring includes an inner groove sized to receive the flanges of the two adjacent pipes. A first end of the inlet insert is inserted into a first pipe and the second end of the inlet insert is inserted into a second pipe. The clamp is placed over the clamping ring. The clamp is tightened to secure the two pipes. A second embodiment of the pipe coupling method includes an inlet insert, and a pair of latch clamps for joining a pipe to a sprinkler pipe. A third embodiment of the pipe coupling method includes an inlet insert, two collars, a peripheral clamp and enlarging a perimeter of two coupled pipes.
