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WIS 4-26-01 Specification for leak tightness of covers for manholes and inspection chambers


This document has been prepared by an active Task and Finish Group comprising representatives of UK water companies, Irish Water, WRc, an independent expert on this topic and nine manufacturers and suppliers of covers and frames for manholes and inspection chambers.

It’s primary aims are to:

  • Provide designers and specifiers with the opportunity to select products appropriate to the location and sensitivity to leakage (inflow) into the drainage system on which the cover is installed.
  • Provide manufacturers and suppliers with a means of testing products against the specification and categorising and labelling their products appropriately.
  • Raising industry awareness of the risk that  ‘foul only’ sewerage systems (pumping stations / treatment plant) can be overwhelmed by leakage (inflow) through relatively small numbers of inappropriately specified covers during their partial or total submergence by surface water.

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