uponor drinking water hygiene

Specifying the correct pipework can prevent Legionella

In this blog we tackle the topic of legionella; the deadly water related infection, which can lead to premature deaths amongst those who are most vulnerable in society. Indeed, the UK government  reported that nearly 700 deaths were registered in conjunction with Legionella last year.

This figure is startling considering the technology and materials we have at our disposal to eliminate this water based infection. For instance, did you know that specifying the right pipework can reduce the threat of Legionella?

But before we discuss prevention methods, it is important to assess what causes Legionella.
Legionella and pipework

What causes Legionella

Legionella has an extraordinary ability to breed exceptionally quickly in any stagnant water within the 25C – 45C temperature range, doubling in number every eight hours. Under utilised areas of pipework are prone to building up stagnant water and this can often cool to within the high risk temperature parameters or rise in temperature within close proximity of hot water pipes.

Although regular checks of taps and sentinel points using thermal probes can help to reduce the issue, they are often vulnerable to human error. Design and specification issues can also lead to a continued threat.
MLC pipework

Specifiying MLC and PEX pipework can help prevent Legionella

So, what can be done to reduce the risk through specification and design? The first area of focus should be the pipe material. By switching from traditional copper piping to MLC (multi-layer composite) pipe or PE-X polyethylene pipe, the specifier can reduce the risk of calcification which can harbour bacterial growth and ensure a smoother internal surface to enable better water flow on the network.

Some common joint methods on copper piping can provide small crevices that can harbour bio-films and bacterial growth, whereas MLC and PE-X pipe systems, which seal on the inside bore, provide a smooth bore and a more hygienic connection. This simple change in specification can remove some of the conditions that support Legionella growth.
Installation methods

Installation methods can prevent Legionella

‘Serial’ installation can avoid dead legs (cause of Legionella) on the network, provided that the most frequently used water outlet – usually the toilet - is placed as the final item on the network so that water regularly flushes through the pipe to reach the frequently-used service. 

The most effective pipework configuration of all for avoiding stagnant water on the system and mitigating Legionella risk is a Loop installation, whereby a small set of services are connected by a continuous loop of pipework ensuring water is flushed through the whole local pipe network every time any water outlet on the system is activated. This completely eliminates dead legs, dramatically reducing Legionella risk.
Uponor Heat Interface Unit

Heat Interface Units

To further reduce the threat of Legionella, Heat Interface Units (HIU's) can be specified. HIU's supply hot water on demand and consequently eliminate the risk of stagnant water. What's more, the installation time can be reduced by over 30% in comparison to alternatives and improved energy savings can be realised.

Uponor's MLC and PEX pipework is compatible with HIU's and can be supplied as a complete solution