ACO Doorway Drain 1m Length. Introduction to the system ACO DoorWay Drain provides simple, unobtrusive threshold drainage compliant with Part M and Section 4 Building Regulations. It is designed for use with doorway systems up to 1000mm wide, however multiple drainage runs can be achieved by simply clipping units together. Manufactured from recycled polypropylene, the 1m channel unit is combined with two Heelguard, friction-fit stainless steel gratings. In addition to the channel unit, all accessories such as end caps and o…