INSPECTING JIG FOR DUCT LINE AND PIPING METHOD USING THE JIG

PROBLEM TO BE SOLVED: To make it unnecessary to prepare a large number of mandrels, by bundling a plurality of inspecting substances having a diameter the same as or larger than a second pipe, and using it as an inspecting jig on the occasion of drawing a plurality of second pipes into a first pipe to perform piping. SOLUTION: An inspecting jig 1 is obtained by arranging each three inspecting pipes 2 longitudinally and transversely respectively, and are bundled with ropes 3 whose each one end is bound to both ends of each inspecting pipe 2. Next, the other end of each rope 3 is connected with wires 5, and it is drawn with a wire 16 into a large pipe such as a trough, a box, a box culvert, etc., reaching a hand hole from another hand hole to inspect a duct line. At this time, inspecting pipes 2 are made and used by cutting a pipe, a straight or corrugated pipe made from synthetic resin for example, by lengths about 30 cm-1 m into a necessary number of pieces. And a plurality of small pipes are drawn into a large pipe and piping is performed, when it becomes possible to insert the inspecting jig into the large pipe. Consequently, preparation of a large number of mandrels becomes unnecessary, and it becomes possible to facilitate piping in a large duct line.