RPZ Valves Uncovered:

In a world of acronyms and abbreviations, it is hardly surprising the profession is struggling to decipher it all. RPZ stands for "Reduced Pressure Zone". An RPZ Valve is basically an extremely reliable non-return valve. This mechanical device is designed to prevent contamination of the Mains water supply and the water system within a building. It prevents contamination by preventing backflow of fluid. The reason you may not have come across the term "RPZ" is because these valves are new to the UK. However, they will become commonplace once designers and installers become aware of the requirements of the new Water Regulations and the advantages these devices offer over conventional break tanks.

New to the UK they may be, but RPZ Valves have been used in America for about 30 years and are known colloquially as "Backflow Preventers". Europe has used RPZ's for about 10 years and they are termed "BA Devices" since this identifies the alphabetical prefix of this family of Backflow prevention devices. European harmonisation will make the name BA Device more common in the UK.

The old Water Byelaws did not allow the use of RPZ's. However many of the water supply companies recognised the benefits and sought specific or a blanket relaxation of their own Byelaws in order to gain experience of these devices. The prescriptive nature of the 101 Byelaws stifled development of the plumbing industry in the UK and this accounts, in part, for the huge differences in engineering standards between traditional UK fittings and those seen in Germany and other European countries.

The range of Backflow Prevention devices now permitted in the UK is considerable. Definitions and examples of applications are described in the Water Regulations and government Guidance. Consulting Engineers and Installers must have a comprehensive understanding of the Regulations in order to select the right device for the application. So let us begin with an overview of the Water Regulations.

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