tions of the Building Research Establishment (BRE, 1984). The recommendations contained in Sewers for Adoption are in Table 4.5.
The diameters for circular manholes are for sewers of 300 mm diameter and less. The BRE recommendations are for building drainage and are similar to those used in North-east Lahoreindeed they suggest that 190 mm diameter chambers are appropriate for invert depths of 600 mm and less. BRE's recommendations for greater invert depths are given in Table 4.6.
One of the most difficult tasks in developing cost-effective approaches to the provision of sewerage within the public sector
