Water Supply Industry Interpretations and Advice

  • Area of Interest : Backflow prevention
  • Topic : Emergency supplies
  • Title : Renal Dialysis units - emergency water supplies to hospitals
  • Clause Reference : Schedule 2 paragraph 15 (1)
  • Reference Number : B03
  • Decision Date : February 2001

In an emergency, an acceptable arrangement, for the direct connection of a hospital renal dialysis unit to a supply pipe, bypassing the normal storage cistern, is via a Reduced Pressure Zone (RPZ) valve (Type BA device), designating the system a fluid category four risk.

A maintenance routine would be required that not only includes the RPZ valve, but also necessitates the regular flushing of the deadlegs up-stream and down-stream of the valve. Any hospital seeking to install such an arrangement should be advised to first establish that the supply pipe pressure is adequate for the supply via an RPZ valve. Hospitals are advised not to place reliance on a continuous mains supply.