With the strain of fresh water availability on our planet, and the need to prevent contamination of water that can lead to the spread of disease, clean water has become both an environmental and public health issue.
The strict guidelines for drinking water hygiene in building industries are a particular challenge. Pipe and fittings material, size and installation methods are all deciding factors for the lasting preservation of drinking water quality.
The ways in which we as a plumbing fittings manufacturer can contribute to water safety is in the design of our products, the materials we use and our compliance with global water safety standards.
One thing that contributes to the protection of public water supplies and encourages the efficient use of water is the testing for compliance and certification of products by the appropriate water protection and standards bodies.
For example, WRAS in the UK actively promotes and facilitates compliance with water supply regulations. We work constantly to ensure our products meet not only WRAS standards, but those of KIWA, DVGW, SVGW and CSTB as well as numerous international bodies.
A substantial investment in testing and certification is carried out, qualifying our products for contact with drinking water, including meeting European standards such as SVGW (the Swiss Gas and Water Association). ATG in Belgium certifies plumbing fittings in copper or bronze for use in cold sanitary water distribution, as well as hot, heating water and cooling water.
Outbreaks of disease from waterborne pathogens continue to be a major concern for organisations such as The World Health Organisation (WHO), the Health and Safety Executive and the Association of Plumbing and Heating Contractors in the UK. Work with governments and partners to support and assist control continues to be through education, vigilant monitoring, prevention and directives for reaction.
The issue of prevention can of course go to the source of the water, as well as issues such as the potential for micro-organisms to grow, the potential for aerosol release and the likelihood and susceptibility of people being exposed to the aerosols. But it is at the design stage of the water network that prevention comes into play. This is where the identification of the right materials to be used can be a key factor in the reduction of diseases such as legionella, pseudomonas and other pathogens.
Proliferation of bacteria such as legionella in water networks can be a major health risk, particularly for people in poor health such as aged care or hospital residents however, it is also finding its way into multi residential locations such as apartment blocks.
Recognising the seriousness of this issue, the EU in 2000 outlined regulations to member states on their responsibilities to provide a consistent water quality policy by 2015, 2021 and 2025. The plumbing industry has a huge part to play in ensuring that quality control is maintained.
Legionella can cause extremely serious infections with outbreaks frequently occurring in healthcare, retirement and convalescence domestic properties, as well as standard private housing. Legionella is caught by inhalation rather than by ingestion and is particularly prevalent in water circuits where, according to HSE, the temperature range is between 25-45°c.
The bacteria are mostly transferred to the atmosphere by aerosol action such as water vapours from air-conditioning systems and faucets. The spread of this type of bacteria depends on certain key elements, such as:
• nature of water
• absence of circulation
• ambient temperature
• lack of ongoing treatment
• choice of pipe work materials used
Using the right materials
Numerous antimicrobial efficiency studies have been conducted in the past 10 years regarding copper’s ability to destroy a wide range of bacteria, including legionella. Therefore copper is trusted to be the safest choice of plumbing material to use in a supply network for potable water, to minimize the possibility of a legionella outbreak.
It is important to point out that bio films and the nutriments they provide are key to the survival of bacteria and that all piping materials develop this bio film formation. Also, over time the data shows no substantial difference in the formation of bio film between copper and many of the synthetic pipe materials commonly used for potable water networks.
However, where copper is beneficial is in its ability to withstand high thermal shocks, whilst maintaining its installed and mechanical characteristics, over a significant period. There is no need for excessive special measures to deal with expansions, such as loops or bellows, and will continue to suppress colonisation and growth of a wide variety of micro-organisms.
Whilst materials, such as copper, are used to minimize the risk of legionella outbreaks, designers and operators should note that copper is not to be installed as a sterilisation disinfectant or way of improving the potability of water.
Stainless Steel assists in the creation of long lasting hygiene and the prevention of the formation of any medium on which bacteria can grow, through the generation of its thin, chromium-rich, self-healing oxide film. This passive film causes stainless steel to be basically inert in drinking water, which maintains water quality.
Soil chemistries, treatment chemicals and water itself can all cause corrosion over time, as well as the erosion corrosion caused by high flow rates. Stainless steel has proved itself much more resistant to high velocity and turbulence than steel, without suffering wall thickness erosion, and is why stainless steel fittings are recommended in the design of drinking water systems.
Conex Bänninger >B< Press Inox fittings are manufactured using solution-treated molybdenum-steel giving the steel its superior strength. When added to steels, molybdenum also enhances corrosion resistance to the full range of potable waters and various chloride levels covered by the EU drinking water directive.
Ongoing surveillance and monitoring
Once installed, system networks should be subject to rigorous protocols to ensure all ‘breakdowns’ in the network are minimised, which will reduce the risk of water sitting in pipes for extended period, increasing the risk of bacterial growth.
If these points are taken on board as an industry, we can minimise the proliferation of legionella bacteria and other pathogens in our water heating systems.
References and further reading: