Ordinary fire engineering grooved pipe fittings have rigid elbows (90 degrees 45 degrees) Positive three-way positive four-way groove Mechanical three-way wire connection Mechanical three-way mechanical four-way conversion flange Split flange groove Reducer wire connection Reducer Pipe grooves have tee wire connection reducing tee, the size includes clamp connection 76 89 114 165 219 (galvanized pipe) 108 159 (seamless pipe) wire connection includes 33 42 48 60 76 89 114 generally 100 (ie 114 outer diameter) above with groove connection 100 below with wire connection.