Keystones of potable water hygiene
Lukewarm, stagnant water is a breeding ground for bacteria. Therefore, drinking water in buildings has to be kept at the right temperature and remain in motion to ensure proper hygiene. The basis for all this is the "effective radius of drinking water quality" with the four essential influencing variables. But even in advance, during the planning and installation stages, preventive measures shall be taken to reduce rsisks from the beginning.
A high potable water quality begins with the planning and the selection of the right material.
Effective radius of potable water hygiene
There are at least three basic requirements to potable water supply systems. The first two are the classical goals. The third requirement has become more and more important in recent years. Due to its character as a foodstuff, drinking water has an "expiry date" which is reached when it does not meet the standard requirements for potable water at the time of withdrawal. Therefore, planners and experts must know and consider the most important factors influencing the quality of potable water.
Against this background, it is particularly important that the drinking water installation is clearly and transparently documented in order to avoid contamination by chemical or microbiological parameters.
| Usage comfort: water quantity, temperature, sound protection |
| System operation and value preservation: safe, sustainable, energy-efficient |
| Maintaining potable water quality |
There are four central, interdependant influencing variables of potable water hygiene: turbulent flow, temperature, water exchange rate and nutrient supply. The effective radius of potable water hygiene sums them up and illustrates: in a potable water installation, the influencing variables must always be considered in a coherent manner.
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Turbulent flow
The flow through the pipeline network stands for the regular use of the entire potable water system. It prevents stagnating water, in which pathogens multiply much faster than usual, and can be achieved by using slim nominal pipe diameters.
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Temperature
Maintaining temperature is crucial as bacteria such as legionella proliferate particularly strongly in hot water (PWH) at less than 50 °C and in cold water (PWC) at more than 25 °C.
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Water exchange rate
In accordance with DIN EN 806-5 (European Union), proper operation of a potable water supply systems requires an exchange of water at least within 7 days (≥ 1x / 7 days). This refers to complete exchange of the water in all partial sections and in the water heater.
Series piping and ring systems to frequently used sampling points can be used to ensure the required water exchange even for little-used fittings, while maintaining economic viability. Under these conditions it is sufficient in the event of interruptions of use to schedule manual flushing or flushing by a flushing system.
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Nutrient supply
In order to remove nutrients from potential pathogens and prevent their growth, it is important to keep the nutritional value in potable water as low as possible.
Precautionary principle
To avoid contamination within a potable water supply system, specific procedures must be followed. This is particularly important in facilities housing people with weakened immune systems, such as hospitals, retirement homes and care homes.
In order to minimise the expense required to remove the contaminants from the outset, it is necessary to avoid the introduction of impurities as far as possible during installation or repair work. To do this, all system components comprising the potable water supply system are to be transported and stored in such a way that internal contamination from earth, mud, dirty water, pathogens, small animals, etc. can be reliably avoided during installation.
From the outset, it is essential to avoid a lack of water exchange in unused pipelines (e.g. guest toilet, outside tap), otherwise there is an increased risk of microbiological contamination.
Special-use buildings, such as hospitals, retirement homes, kindergartens, schools, also require a hygiene plan. This hygiene plan must contain information and instructions for the increased requirements of the maintenance measures and actions to be taken in the event of faults and incidents.
Additional requirements or measures:
| All pipelines, fittings and appliances are to be delivered with protective caps during transport. |
Press connectors are to be delivered in shrink-wrapped transport bags. After the bags are opened, they are to be stored in airtight containers (also in the material container). |
| Fittings must be sealed with protective plugs or caps to ensure they remain airtight until installation. |
| Fittings, appliances, pipelines or press connectors which show any visible residues or deposits must not be installed, but are to be cleaned and disinfected or removed from the construction site. |
| It must be ensured during assembly that all pipe ends and fittings are sealed with protective caps during all breaks in work. |