non-mechanical & mechanical backflow protection

What is the air gap?

Hint 1: 'Air gap with unrestricted discharge' means a non-mechanical backflow prevention arrangement of water fittings where water is discharged through an air gap into a receptacle which has at all times an unrestricted spillover to atmosphere

Hint 2: A good example of the use of this air gap is in the form of an animal drinking trough

• AA

• AB

• AC

• AD

What is the air gap?

Hint: 'Air gap with weir overflow' means a non-mechanical backflow prevention arrangement of water fittings complying with Type AA, except that the air gap is the vertical distance from the lowest point of the discharge orifice which discharges into the receptacle, to the critical water level of the rectangular weir over flow

• AA

• AB

• AC

• AD

What is the air gap?

Hint 1: 'Air gap with injector' means a non-mechanical backflow prevention arrangement of water fittings with horizontal injector and a physical air gap of 20mm or twice the inlet diameter (whichever is greater).

Hint 2: #the practical application of this arrangement is in a commercial washing machine.

• AA

• AB

• AC

• AD

What is the air gap?

Hint 1: 'Air gap arrangement with minimum size circular overflow' means a non-mechanical backflow prevention arrangement of water fittings with an air gap

Hint 2: Likely to be installed in cold water storage cisterns

• AC

• AD

• AF

• AG

What is the air gap?

Hint 1: 'Air gap with interposed cistern' means a non-mechanical backflow prevention arrangement consisting of a cistern with type AG overflow and air gap; the spillover level of the receiving vessel (WC pan) being located no more than 300mm below the overflow pipe, and not less than 15mm below the lowest level of the cistern.

Hint 2: Typical application WC

• AG

• AUK1

• AUK2

• AUK3

What is the air gap?

Hint 1: 'Domestic tap gap' The fluid category 2 or 3 risk is present downstream.

Hint 2: Typical application hot and cold taps in a cloakroom

• AA

• AUK1

• AUK2

• AUK3

What is the air gap?

Hint 1: 'The higher risk tap gap' where a fluid category 4 or 5 is present downstream

Hint 2: typical application kitchen sink

• DC Interrupter

• AUK1

• AUK2

• AUK3

What is the air gap?

Hint 1: 'Pipe Interrupter' with permanent atmospheric vent' means a non-mechanical backflow prevention device with a permanent unrestricted air inlet, the device being installed so that the flow of water is in a vertical downward direction

Hint 2: typical application found in urinals

• AUK3

• AF

• AG

• DC Pipe Interrupter

What is the air gap?

Hint 1: 'Verifiable backflow preventer with reduced pressure zone' means a verifiable mechanical backflow prevention device consisting of an arrangement of water fittings with three pressure zones

Hint 2: Provide protection against fluid category 4. These devices need specialist competency to install and are notifiable to the water undertaker

• CA

• BA (RPZ)

• DA Anti Vacuum Valve

• AF

What is the air gap?

Hint 1: 'Pipe interrupter with atmospheric vent and moving element' means a mechanical backflow prevention device with an air inlet closed by a moving element when the device is normal use, but which opens and admits air under fault conditions - discharging to atmosphere.

Hint 2: Typical application hose union bib tap, protection against fluid category 4

• DB

• DA

• CA

• BA