Case Study 44 – What is a D&C R40?

The R40.1 specifications states “The drain pipe must be of rigid unplasticised polyvinyl chloride (UPVC) complying with AS 1477.1 and have a strength grade of Class 18.”

Each drain comprises an inner and outer pipe, and the outside diameters and the wall thickness must be as given in Table R40.1 below:


If you need a copy of the RDA D&C R40 specifications the link is below:

A UPVC cap complying with the same standard must be fitted to the upstream end of each drain pipe.

The pipes must be provided with slots of width between 0.90 mm and 1.10 mm, extending to a minimum depth equal to 3/8 of the outside diameter of the pipe and a maximum depth equal to half the outside diameter of the pipe, and spaced at 25 mm apart.

The slots must be cut in groups of twelve. Each set of twelve slots at 30° to the horizontal and orientate each alternate group to lie within the top 240° of the circumference. In this fashion, the bottom 120° of the circumference of the pipe remains uncut over its entire length (see Figure R40.1).

The pipe must be un-slotted for a length of 1 m from the outlet end, or whatever length as directed by the Principal.

The problem here is there is no pipe that has a  75mm OD , the closest is 80mm which has a od of 88mm, but if it has the bell on the pipe( 103mm) this will not fit into the 114mm od pipe.

This is a dilemma as by using another size pipe, it then does not meet the standards.

By using a special size pipe Deps has overcome this problem.

If you need any more info please contact us on 1300 133 000