NFORM TO AMERICAN SOCIETY OF MECHANICAL ENGINEERS ASME 112.19.2 (VITREOUS CHINA PLUMBING FIXTURES) AND THE HYDROLIC REQUIREMENTS OF ASME 112.19.6 (HYDROUC PERFORMANCE REOUIREMENTS FOR WATER CLOSETS AND URINALS). 2. WATER CLOSETS THAT PERMIT THE BACKFLOW OF THE CONTENTS OF THE BOWL INTO THE FLUSH TAN