Pressure Tight Joints
Pressure tight joints for low pressure service are sometimes made with straight internal threads and the American standard taper external threads. The ductility of the coupling enables the straight thread to conform to the taper of the pipe thread. In commercial practice, straight-tapped couplings are furnished for standard- weight (schedule 40) pipe NPS 2 (DN 50) and smaller. If taper-tapped couplings are required for standard-weight pipe sizes NPS 2 (DN 50) and smaller, lin
