RPZ valves are installed to protect "wholesome" water (ie drinkable potable ) mains water against possible contamination in Category 4 fluids. Examples of use are listed on the home page.
The RPZ valve should not be used ( with fluid Category 5 ) where there is a risk of contamination involving Human or Animal Waste, Pathogenic or Radioactive substances or Very Toxic situations. Usually Mortuary, Farm, Butchery & Slaughterhouse premises are not suitable.
RPZ Valve Installation
The Valve should be installed horizontally, above ground with the relief valve discharging downwards into a drain or safe area. It should be in a "tamper free" environment but capable of inspection and maintenance. The Valve should not be subject to flooding or freezing or near electrical equipment.
RPZ valves have been protecting water supplies in the USA for over 30 years and are now becoming widely used in the UK.