Safety fitting

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A safety fitting is a fitting that protects the drinking water from contamination. The aim is to prevent liquids such as contaminated drinking water, waste water or industrial water from entering the pipe network. A backflow as a result of suction or pressure can e.g. B. occur when the shower hose falls into the full bathtub, when an outlet hose is immersed in a vessel or when a hose connection to a household appliance or to fill the heating system is made.

If there is a connection between service water and drinking water, service water can flow back into the drinking water line if

  • A higher pressure arises in a device than in the associated piping system or
  • the pressure in the drinking water system drops because
    • a valve with a high flow rate has been opened on a lower floor , e.g. B. the flush valve of a toilet,
    • the drinking water pipe has been shut off and a valve in the shut-off pipe section has been opened,
    • A pipe burst has occurred in the drinking water connection line (e.g. due to construction work or earth faults),
    • During maintenance work, the main line is emptied and the pipe network above it runs empty.

Safeguards

Incomplete list, roughly sorted in order of effectiveness:

  • free run (safest facility)
  • Pipe interrupter A1,
  • Pipe separator installation type 3,
  • Pipe interrupter A2,
  • Pipe separator GB (installation type 2),
  • System separator / pipe separator BA, pipe separator GA (installation type 1),
  • System separator / pipe separator CA, GA
  • Safety combination,
  • Backflow preventer and
  • Pipe aerators of shapes C, D and E.

Safety fittings differ from safety fittings such as B. Safety valves , which prevent the creation of dangerous overpressure.

Applications

If a hose is connected to a drinking water tap to clean the drainpipe, a pipe interrupter can prevent contamination of the tap.

When using a hose, the water at the end of the hose must be able to flow freely and unhindered. As soon as the end of the hose is in a container or is firmly connected, a safety fitting must be used in accordance with the now valid EN 1717.

When connecting the hose to top up the water in a heating system, a system separator type CA or GA can be used if no additives have been added to the heating water (hazard class 3). If additives are used, a system separator type BA (hazard class 4) is required.

Guidelines

Since 2001, EN 1717 has been in force together with the previous DIN 1988 Part 4. The latter is to be withdrawn after EN 806 Part 1 - 5 comes into force.

The selection of the safety fitting is based on the hazard class of the drinking water according to DIN EN 1717.

Families of safety fittings:

  • Family A Free exercise
  • Family B Controllable separation (usually recognizable by three test valves with which pressure loss in connected lines is simulated and the medium pressure zone is controlled)
  • Family C Unmanageable separation
  • Family D Atmospheric ventilation devices
  • Family E backflow preventer
  • Family G pipe separator
  • Family H ventilation fittings for hose connections
  • L Family Pressurized Aerators.

The fittings are marked with two capital letters, the first of which designates the family specified above and the second specifies the type of fitting.

Safety devices with atmospheric ventilation (e.g. types AA, BA, CA, GA, GB etc.) must not be installed in rooms or shafts where there is a risk of flooding or where toxic fumes can occur.

A safety device consists of the actual safety fitting and the accessories according to DIN EN 1717, which ensure proper functioning over the long term and enable testing and maintenance. These include shut-off valves and screw connections for easy replacement of a defective fitting, dirt traps to maintain the function of check valves and valves for functional testing by simulating a pressure drop.

Web links

Individual evidence

  1. ↑ a b c Dipl.-Ing. Tino Reinhard: The meaning and content of DIN EN 1717 - system standard regulates drinking water protection across Europe , IKZ Haustechnik, issue 13/2006, p. 32ff
  2. ↑ Tino Reinhard: Safety concept and safety fittings according to DIN EN 1717 in energie | wasser-praxis , October 2008 edition, online at www.fachzeitschriften-wvgw.de ( Memento from June 16, 2012 in the Internet Archive )
  3. ↑ a b twin - Information from the DVGW on the drinking water installation system separator ( memento of the original from September 3, 2013 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. , As of April 2003 @1@ 2Template: Webachiv / IABot / www.dvgw.de