Explanatory notes
… to non-refractory piping, etc., designed, as a general rule, to interlock and to be used for draining or for the … drain-pipes, sewer pipes, conduit tubing to protect electric cables but not designed to act as insulators, half … or branching (collars, flanges, elbows, T-pieces, clean out traps, etc.). The heading does not cover : (a) …