Water Supply Industry Interpretations and Advice

  • Area of Interest : Backflow prevention
  • Topic : Fluid category
  • Title : Flushing water systems prior to commissioning
  • Clause Reference : Schedule 2 paragraph 15 & G15.3
  • Reference Number : B12
  • Decision Date : February 2002

The Fluid Category risk of a newly installed water plumbing system before flushing and commissioning is considered to be not more than Fluid Category 3. Rapid filling of the system would be permitted using a temporary connection by means of a hose of no greater than 25mm (1”) diameter, protected against backflow by a double check valve, unless a risk assessment, taking into account specific circumstances, indicates that a higher level of backflow protection is required.