Separation stations and drinking water feeding

Ensuring clean water is of fundamental importance for human well-being. In many countries, public drinking water supplies are therefore specially protected. It is well known that water once leaked from the public supply system can potentially be contaminated or microbially polluted. Therefore, it is of utmost importance to ensure that water from connected facilities does not re-enter the drinking water network.

To the products

WISY recommendations

For the protection of drinking water

Protect drinking water

Clean water is indispensable for humans. This is why the public drinking water supply enjoys special protection in many countries. Water that has once left the public supply area can be contaminated or microbially polluted. Therefore, it must not be allowed to get back into the drinking water network from connected facilities.

Free run

The safest way to prevent backflow is the free outlet. According to the standard, this is a "permanently unimpeded free flow path" for the water. It therefore falls freely downwards into an intermediate tank from which it cannot flow back.

A pump then builds up the required system pressure, which has dropped to ambient pressure through the free outlet. The volume of the intermediate tank, the type of pump and the pipe cross-sections are adapted to the desired pressure and volume ratio.

DIN EN 1717 AND DIN 1988-100

Throughout Europe, the requirements for the type of system separation are regulated by the EN 1717 standard. It has been adopted and supplemented for Germany by DIN EN 1717( ) and DIN 1988-100( ). Depending on the potential hazard, categories are defined for liquids that can come into contact with drinking water. The liquid categories are designated with the numbers 1 to 5. Category 1 corresponds to water for human consumption. Liquids that are hazardous to health due to microbial or viral pathogens fall under category 5.

Safety devices according to standard

According to the hazard potential, appropriate safety devices are prescribed. These are divided into types and designated with a combination of two letters.

Fluid category 5

According to the European standard, liquids of category 5 may only be used by means of safety devices with free discharge of types AA, AB, AD or, to a limited extent, type DC. The German standard gives concrete examples of tapping points or apparatus whose liquid falls into this category. Examples of applications where a standard-compliant separation must be made are:

  • Activated carbon filters in chemical apparatus
  • Tank filling, e.g. tank trucks
  • Sprinkler systems, underfloor systems
  • Fish tanks
  • Rainwater harvesting
  • Meat and fish processing machines
  • Galvanic plants
  • Glass rinsing equipment, e.g. at bar tables
  • Potato peeling machines
  • Cooling circuits, cooling towers
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