One of the recurrent themes of these columns over the past couple of years has been the need to encourage the use of modern simulation and analysis tools to aid in the modernization of building drainage system design. It is essential that new solutions be found for some of the oldest problems faced in system design; however, it is also essential that these new solutions be accepted in practice. Perhaps the greatest challenge comes in the introduction of new appliances that imply changes in long accepted design approaches. While our industry rightly considers safety its prime objective, it is important that such concerns are not used to block the discussion, investigation and subsequent possible acceptance of new approaches.