Prefix DX - Designates a wide flange that can be furnished on certain Smith Cleanouts. This flange receives and serves as a bonding base for the membranes and coatings of waterproof floor covering systems. These coverings consist of thin coatings which are applied in a series of trowel coats. The covering forms its own membrane, flashing and durable traffic surface. The wide DX flange is regularly furnished 4" in width. The usual covering is approximately 3/16" thick and may be applied over many sub surfaces such as concrete, gypsum or wood decks. Such coverings are particularly adaptable to areaways, plazas, floors and corridors.

When DX flange is required on cleanouts other than those shown in this section, the prefix DX must be used with the figure number and the lip dimension must be specified. If waterproof deck covering thickness is greater (or less) than 3/16, the lip dimension must be specified. Cleanout body should be set to compensate for the variation in thickness. Cleanout body should be set low enough to permit "dimpling" of area surrounding drain.

Illustrated is a typical waterproof traffic bearing floor covering installation and an example of the "dimpling" effect.