Irrigation Components

Question 1

Atmospheric Vacuum Breaker (AVB)

Answer 1

Incorporates a floating disc which when pressurized, rises and seals off the air inlet.
Prevents Back Siphonage
Must be installed vertically and a minimum of 6” above the highest head
Cannot be subject to more than 12 hours of constant pressure in a 24 hour period.

Question 2

Pressure Vacuum Breaker (PVB)

Answer 2

An air relief valve opens at low pressure and stops any backsiphonage
Must be installed vertically and a minimum of 12” above the highest head or outlet.
Designed to handle constant pressure
Approved for health hazard where there is no threat is back pressure.
2 shut off valves, 2 test cocks for testing the device.

Question 3

Air Gap

Answer 3

The unobstructed vertical distance through free atmosphere between the lowest point of water supply outlet and the flood level rim of the fixture or assembly into the outlet discharges.

These vertical, physical separations must be at least twice the diameter of the water supply outlet, but never less than 1” in diameter.

Question 4

Double check assembly (DCA, DCVA)

Answer 4

Utilizes two spring loaded check valve assemblies to protect against backsiphonage AND back pressure.
It can be installed horizontally or vertically and above or beneath the ground.

It has two shut off valves. It can handle constant pressure and is approved for non-health hazard applications ONLY. Has 4 test cocks.

Question 5

Reduced Pressure Principle Device (RP, RPZ, RPP)

Answer 5

Approved for health hazard conditions, protects against backsiphonage and back pressure and offers the most protection of any mechanical device.

4 test cocks cocks. Two shut off valves are present. Must be installed horizontally with a minimum of 12” above grade in a location that cannot be submerged. It can handle constant pressure and is required when a fertilizer injector are being used.

Question 6

What is an unwanted reversal of water flow in an irrigation system?

Answer 6

Backflow

Question 7

A cross connection is any actual or potential connection between a portable water supply and:

Answer 7

Any source that has the possibility to introduce polluted or contaminated water back into the potable water that is supplying it.

Question 8

Backsiphonage is caused by:

Answer 8

Negative or sub-atmospheric pressure

Question 9

What can cause backsiphonage?

Answer 9

A break in the city main and the fire department using water to put out a fire.

Question 10

If the pressure in the sprinkler system (or downstream side) exceeds the pressure in the supply side, what phenomenon can occur?

Answer 10

Back pressure

Question 11

What causes back pressure?

Answer 11

Gravity and a pump.

Question 12

The vertical, physical separation, in an air gap must be:

Answer 12

At least twice the diameter of the water supply outlet, but never leas thank 1 inch.