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Pipe Int. DB 1/2" Inter-Lock Hose Conn.

The type DB Pipe Interrupter is a backflow prevention device for specific Fluid Category 4 applications. The DB device is often fitted to a Hose Union Tap to improve the level of backflow protection. The principle is similar to traditional bicycle tyre valves, where the flow enters a tube with the far end blanked off. This tube has several small radial holes, over which a flexible tube is stretched. The forward flow lifts the flexible tube and pushes it against the outer vent holes. When the supply pressure is released, the flexible tube contracts venting the downstream and covering the inlet holes. The DB Pipe Interrupter is approved for back siphonage protection – not back pressure. DB Pipe Interrupters are generally used externally and must not be used for washing machines or any appliance that has a control valve or restriction. They are resistant to frost damage.
Product Code: DB20IL15
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Additional Information

Fluid Category 4 - Size DN20
Fluid Category 4 - Powered No
Fluid Category 4 - Requires Annual Testing No


The main application identified in the Water Regulations Guide is for porous hose モleakyヤ irrigation in a house garden. Water companies may accept small non-house porous hose applications in non-house situations.

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Specification Clauses

Every Hose Union Tap shall be fitted with a DB Pipe Interrupter, suitable for fluid category 4 backsiphonage protection – model DB20IL15 - as distributed by Arrow Valves Ltd – Tel 01442 823123 www.arrowvalves.co.uk.  The device shall be fitted vertically and at least 300 mm above the spillover level.  No valves must be fitted downstream of the device.  The body of the valve shall be chrome plated brass with DN20 female inlet, 15 mm male outlet with hose connector.