This standard applies to mobile backflow preventer B-FW for fire brigade use at a nominal pressure PN of 1,6 MPa (16 bar) and defines its characteristics. The mobile backflow preventer B-FW is connected to existing standpipes or hydrants without integrated system separators for water delivery from the pipe network. It is intended to prevent water from flowing back into the drinking water supply network by sucking back or backpressure when the pressure in this network is lower than in the installed water line.