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Backflow preventer BA always on the safe side

"If non-intrinsically safe devices or non-drinking water-carrying lines are connected to a drinking water installation, a suitable safety device according to DIN EN 1717 is necessary. The BA backflow preventer prevents the backflow, back-suction, or backpressure of harmful liquids up to category 4 into the drinking water pipeline, thus providing optimal protection."

  • DN20 
  • DN40 
  • DN50 
Certified acc. to
  • DN20/DN40: DVGW W 570-1, DIN EN 12729 
  • DN50: DVGW W 570-3, DIN EN 12729, DIN 3509 

Technical structure

Functional principle

If no water is being drawn, both the inlet and outlet check valves, as well as the drain valve, are closed.

During water withdrawal, both the inlet and outlet check valves are open. The drain valve is closed.

During backflow, the pressure on the inlet side drops. If the pressure difference between the inlet and middle pressure chamber is slightly above 140 mbar, the inlet check valve closes, and the drain valve opens. In the case of backpressure, the outlet check valve closes. If the check valve is leaky, the drain valve opens.

Regulative background

The Drinking Water Ordinance, in § 17, describes the necessity of using a suitable safety device according to DIN EN 1717 if non-intrinsically safe devices are connected to a drinking water installation or if the system is connected to a non-drinking water-carrying line. If devices or apparatuses in a drinking water installation are not properly secured, it may lead to the backflow, suction, or pressure of harmful liquids into the drinking water pipeline. It is not always predictable which category the water at the installation site belongs to. In the case of mobile drinking water supply with temporarily installed systems, contaminated water of fluid category 3 and 4 is often encountered. Such liquids can directly affect health and pose a risk to consumers. The currently commonly used safety combination (pipe vent in combination with a check valve) according to DIN EN 1717 cannot cover every use case. To securely prevent the backflow of substances up to category 4 into the drinking water installation, the backflow preventer BA (according to DIN EN 1717, a "pipe separator with controllable middle pressure zone") is used as an approved safety device.


Your contact person
Christian Meinerzhagen
Customer support

Testing of backflow preventers

according to DIN 806-5

According to DIN standard 806-5, a backflow preventer must be inspected at least semi-annually and serviced and checked annually. Additionally, DIN standards 12729 and DIN EN 1717 emphasize regular maintenance to ensure that technical components meet the high requirements for protecting drinking water. The fundamental aspects of component maintenance in drinking water installations are regulated in DIN 806-5.

Benefit from the expertise of our inspection service and have the annual inspection carried out quickly and accurately by our experienced service staff. BEULCO Service maintenance packages include on-site inspection, optional cleaning, and repair of backflow preventers. We will remind you in a timely manner of the next scheduled inspection date and arrange a suitable appointment.

Backflow preventer BA acc. to DIN 12729