Substitute materials. Wood culverts for steel. Assembly of an emergency sectional wood pipe, twenty-four inches in diameter. These pipes, used in place of corrugated iron or reinforced concrete pipes, are made of sections cut from short lengths of wood. Locking of adjacent rings with hardwood dowel pins produces a flexible structure. About 100,000 feet of these wooden pipes were installed in 1942 in drainage culverts, storm sewers and conduits under highways and at army camps, naval stations, airfields and ordnance plants