In 2012, BS 6700 was deactivated to be replaced by BS EN 806. With the implementation of the BS EN 806, several requirements have been changed and it is worthwhile to have a thorough understanding of these if you are a plumber, a contractor or even an owner of an establishment.
 
In particular, BS EN 806 covers the specifications required for installation of systems used for delivery of water for human consumption inside a building. The document is comprised of five essential parts: general specifications, design, pipe sizing, installation and operation and maintenance, which includes legionella testing.
 
The objectives of the document are three-fold. First, it seeks to prevent water deterioration. Second, it sets the requirements for water flow and pressure, particularly at the draw-off points and appliances. Finally, it seeks to ensure that potable water standards are met in terms of the physical, chemical and microbiological aspects at draw-off points. In summary, the goal of the document is to ensure that the water inside a building as well as the system used for its delivery do not pose damage to users. The document defines potable water as water that is fit for human consumption and conforms with regulations based on ECC directives.
 
In terms of design, the documents outline the requirements for designing systems used in distributing potable water within a building as well as the pipework within the premises of the building to include those found outside.
 
In general, the guidelines found in BS EN 806 are aimed at fulfilling several important goals. These include avoidance of waste, misuse, contamination, low flow rates, excessive velocity, stagnant areas, trapped air and air lock formations. In order to achieve this, due care must be given to water outlets as well as other factors including flow rate, water temperature and pressure.
 
The document also specifies the factors that should be used in choosing materialsto be used in a water system. These criteria include a material's effect on water quality, water pressure, temperature, corrosion, durability and compatibility with other materials. BS EN 806 expressly prohibits the use of both lead pipes and fittings.
 
If hot water systems are going to be used within a building, BS EN 806 expressly states that the growth of legionella bacteria must be prevented in conformance to existing national and local regulations. Along with knowing how to test for legionella, designers and installers should ensure that appropriate measures like insulation are put into place.
 
Finally, the documents delve into suitable pipe design to include selection of appropriate materials, consideration of water conditioning, storage, jointing and other factors that influence corrosion.

+Duncan Hollis