25/06/2024

Many laboratory or building users do not focus on the drinking water system. True to the motto: "In Germany, drinking water comes out of the tap." Most people only realize that clean and germ-free water is not a matter of course and that everyone who runs a laboratory has to do their homework and fulfill their duties as an operator when they take a closer look at this topic.

Mr Gahmig, could you start by giving us an overview of what exactly is meant by drinking water hygiene and what legal principles need to be observed?

Maximilian Gahmig: Drinking water hygiene encompasses all measures that help to ensure that drinking water is available in perfect quality. This starts with water extraction and extends to distribution in buildings. The requirements of the German Drinking Water Ordinance (TrinkwV), which specifies the limit values for various microbiological and chemical parameters in drinking water, are essential here. The ordinance also specifies at what intervals and in what way the water must be tested in order to prevent any risk to the health of users. These regulations are particularly strict, as contamination in drinking water can quickly lead to serious health problems.

A key aspect of drinking water hygiene is the network protection concept. Can you explain what this means?

Maximilian Gahmig: The network protection concept is an integral part of drinking water hygiene and aims to prevent contamination of the drinking water network. It documents the pipes and various drinking water consumers and categorises them in terms of their risk of contamination. Machines and laboratory equipment that are permanently connected to the drinking water network are particularly critical here. In order to ensure that the water from industrial processes cannot flow back into the general drinking water network even in the event of a pressure drop in the main network, these areas of the water network may need to be isolated from the main network by means of network protection devices. It is important to use suitable safety fittings here, as normal drinking water fittings do not provide a sufficient barrier for microbially or chemically contaminated water.

What is the importance of regular water quality testing and how is this carried out?

Maximilian Gahmig: Regular water quality testing ensures that all legal limits are met and that the water is free from harmful germs and substances. These tests are carried out at least once a year, but often at shorter intervals to ensure continuous monitoring. The samples are taken at various points in the network and tested for a variety of parameters, including microbiological germs such as legionella, E. coli or pseudomonads, but also chemical substances such as heavy metals. The results of these tests form the basis for any adjustments and measures to ensure water quality. This can be quite time-consuming.

The VDI/DVGW 6023 guideline stipulates a complete water exchange every 72 hours in the entire pipe network. Why is this important and what challenges does it pose?

Maximilian Gahmig: Changing the water every 72 hours is intended to prevent water from stagnating in the pipes, as stagnant water is an ideal breeding ground for germs and bacteria. This requirement is particularly challenging in areas with low utilisation. For example, we need to ensure that water is replaced regularly in areas that are rarely used, such as meeting rooms or during office holiday periods. This requires a minimum water draw-off and appropriately sized pipe diameters to ensure a continuous flow of water.

What could such an automatic dishwashing system look like? Can you tell us more about it?

Maximilian Gahmig: Automatic flushing valves and their integration into the building management system are essential measures for ensuring compliance with drinking water hygiene. They ensure that water is flushed through the pipes at set intervals to prevent stagnation. These systems can be programmed to meet the specific requirements of the building and are particularly useful in areas with irregular usage. Integration into the building management system makes it possible to monitor, control and document the flushing processes centrally. This allows us to ensure that all necessary flushing processes are actually carried out and at the same time optimise water consumption. This technology also makes it possible to take immediate action in the event of deviations, thus ensuring even better drinking water hygiene. Depending on the size of the drinking water network and the initial situation in the project, we can cover this monitoring and control of the drinking water supply with plug & play solutions or integrate it into an existing higher-level building management system. This allows the entire building to be controlled centrally.

Another problem is dead leads. What exactly are they and why are they so problematic?

Maximilian Gahmig: Dead pipes are sections in the water network where there is no regular exchange of water. This can be the case, for example, when a washbasin is dismantled. The pipes are shut down, but not completely disconnected from the network. The remaining pipes lack the necessary circulation, allowing germs and bacteria to colonise and multiply.

As they represent one of the greatest risks to drinking water hygiene, the VDI standard 6023, for example, stipulates that pipes must be dismantled or disconnected directly at the last branch of the system through which water flows. This ensures that decommissioned pipes are completely disconnected from the network and do not pose a risk to drinking water hygiene.

How important is it to document the water network and what are the benefits of simulating the flushing behaviour?

Maximilian Gahmig: Complete documentation of the water network is extremely important in order to fully understand and monitor the structure and functioning of the network. This includes the precise recording of all pipes, fittings and network protection devices as well as the utilisation of space in the buildings. The simulation of flushing behaviour also makes it possible to analyse and optimise water exchange in various scenarios. For example, the trend towards mobile offices means that many offices and toilets are used less frequently, which can lead to problems with drinking water hygiene. Using a simulation, we can determine how long and to what extent flushing is required to ensure that the water is completely renewed. This contributes significantly to safety, but also to the efficiency of flushing measures, as it helps to minimise water consumption.

Such a simulation is also particularly helpful for older drinking water networks that were originally designed for a higher number of users. If 100 production employees used to use 30 showers twice a day and now only 25 employees per day, the water movement is often not sufficient to ensure adequate hygiene. The simulation makes it clear where and how intensively flushing is required to ensure flawless water. This is particularly important in shower rooms, as legionella and pseudomonads, for example, are especially dangerous if they are inhaled via fine spray mist.

You look after many buildings with integrated laboratories at Industriepark Höchst. Can you give us an example from the laboratory environment where the Drinking Water Ordinance applies but is often forgotten?

Maximilian Gahmig: We are not only responsible for the drinking water supply for all the rental buildings at the Höchst site, Infraserv also operates many of its own laboratories there. That's why we deal very intensively with laboratory issues and the topic of drinking water hygiene in laboratories. One example from the laboratory that is often overlooked is eye showers and emergency showers. According to laboratory guidelines, the function of these showers must be tested monthly. However, the Drinking Water Ordinance and VDI standard go one step further and require the water in the supply line to the shower head to be replaced every 72 hours. To make it easier to fulfil this requirement, adapted showers with fittings directly on the shower head can be used, for example. This reduces the stagnation line and the water can be replaced quickly and efficiently.

Finally, Mr Gahmig, what advice do you have for companies when it comes to drinking water hygiene?

Maximilian Gahmig: Ensuring drinking water hygiene is a complex task that requires in-depth expertise and continuous attention. It is therefore essential that companies work with specialised experts in order to comply with legal requirements and protect the health of users.

Mr Gahmig, thank you for this informative interview!