G. J. EDGELL British Ceramic Research Limited

A method of water testing has been agreed in BSS30J but not a criterion for acceptability. This paper describes a series of tests to establish the relative importance of some of the factors relating to construction and workmanship and also the likely leakage rates in well constructed manholes. The results indicate that the filling of joints is important, although their width is less important than might have been expected. Leakage is often associated with the positions of pipes through the walls, but not with step iron locations. Manholes made from perforated bricks are not prone to more leakage than those from solid brick, workmanship aspects are more important than choice of clay brick type. The leakage rate from well constructed manholes is, in the long term, low and any test will need to allow for the fact that there is a decay in leakage rate over an extended period.