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.
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WISY recommendations
For the protection of drinking water
Product information
Sigura 9 break tank
The SIGURA 9 separating station separates the points of use for process water from the public supply network, thereby protecting the public drinking water from contamination. The drinking water backfeed is designed as a free outlet in accordance with DIN EN 1717 and DIN 1988-100.
The SIGURA 9 separating station is installed in the frost-free plant room, draws drinking water from the mains and feeds it under pressure into the service water network. It supplies up to 4.5 bar pressure in the service water network and is also suitable as a pressure booster system for buildings with up to three storeys.
Important details
Product information
Sigura 350 break tank
The SIGURA 350 separating stations safely separate domestic hot water systems with a standard-compliant free outlet type AF from the public mains and build up the required operating pressure. The intermediate tank holds 350 litres and serves as a buffer to quickly provide the required volume flow in the domestic hot water system.
The pump is controlled by the Zeta 02 automatic switch and requires only 0.2 watts in standby mode. The pressure in the domestic hot water system is generated either by the Multigo 205 (80 l/min) or 407 (120 l(min) submersible pump.
Important details
Drinking water top-up
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:
