SANHA Leads the way
SANHA explain the importance of the new 2013 EU Directive on Drinking Water Quality. Lower permitted lead levels in drinking water are making the issue of lead in plumbing installations very important. SANHA explain the back ground to the regulations and how they are tackling the issue with the launch of a new innovative Lead Free range of fittings.
The new European Drinking Water Directive comes into force on 25 December, 2013, setting new legal requirements for the microbiological and chemical-water quality of drinking water.
Crucially, the new legislation (DWD98/83/EG ) introduces a revised limit for the lead content of drinking water of 10μg/litre, a reduction of 60% on the current limit of 25μg/ litre.
It is a mandatory requirement that contractors and installers comply with all relevant legislation, which means installers have a responsibility to adhere to the limit for permissible levels of lead. From a contractor’s perspective the figure of 10μg/ litre is actually more onerous that it might sound, because half of the allowable lead concentration may already be present in the drinking water from the water supplier.
Lead can occasionally occur naturally in groundwater, but this is rare in the UK, where the principal source of lead in drinking water is from existing lead service pipes. Lead used to be a common material for smaller water pipes and water mains, however, its use was prohibited from the 1970s onwards after it was shown that lead can have an adverse effect on the mental development of infants and children. Although lead has not been used in pipework for decades, many pipes still remain in older properties – often as the service pipe connecting the water main to the house, especially if the kitchen has not been modernised.
The problem with lead pipework is that the metal can leach from the pipe walls into the water supply. The issue is lessened in hard water areas because of the scale that forms on the inside of the pipes, which helps protect against the dissolution of lead. In soft water areas, water companies generally treat the water with orthophosphate to reduce the problem, however this does not completely eradicate it.
The Drinking Water Inspectorate, the independent government body set up to monitor the quality of water supplied by water companies in England and Wales, says that even when orthophosphate is present “particles of lead may build up in these older pipes and intermittently appear in tap water”.
Another cause of lead in drinking water is the illegal use of lead-based solder to join together sections of copper pipe. Lead solder is sold for use on closed-circuit central heating systems, but its use on drinking water systems is banned. Nevertheless, lead fittings do still occasionally find their way into these systems when householders carry out their own plumbing work or an unqualified plumber incorrectly installs a system.
In addition to established sources of lead in drinking water, the significantly lower limit for lead content resulting from the directive will increase the focus on other, less familiar sources of lead in water supply systems.
One such source is brass and other alloys used in the manufacture of fittings. Lead is often added during the process in concentrations of around 2% to enhance machinability. Since lead has a lower melting point than the other constituents of these alloys, it tends to migrate towards the surface of the alloy where it can more easily leach into the water supply.
Cutting operations can also smear the lead over the surface. These effects can result in significant amounts of lead from alloys (of comparatively low-lead content) leaching into drinking water for a considerable period of time after their installation.
Manufacturers are faced with a major challenge with regard to the purity of the components produced for drinking water installations. It is now already clear that a number of the copper alloys offered on the market today will not meet the new statutory obligations.
To ensure they don’t fall foul of the latest changes to the water regulations, installers should be much more vigilant in checking the fittings they choose.
Sanha, a German manufacturer of pipes and fittings, has launched a range of patented lead-free components to help installers comply with their obligations.
The advantage of using guaranteed lead-free fittings is that it will give installers complete assurance that if lead is detected in a system, it must have originated from the water source or elsewhere upstream of the works.
(Barny Parks is managing director, Sanha UK)
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