What is required for a sprinkler system?

DOUBLE CHECK, MINIMUMBackflow Double Check

The plumbing code mandates as minimum protection, a Double Check backflow device.

Some municipalities have mandated a higher level of protection, namely a Reduced Pressure Backflow Assembly.

Information specific to you municipality can be found here: Municipal watering restrictions

Do I need to install a backflow device?

YES, IF YOU ARE CONNECTING DIRECTLY TO THE PLUMBING SYSTEM OF THE BUILDING

All new systems must be protected.

YES, IF YOU ARE MODIFYING THE PLUMBING TO THE SPRINKLER SYSTEM

Any modifications require us to bring the system up to code.

MAYBE, IF YOU ARE CONNECTING TO A TAP OUTSIDE

It will depend on the type of tap that is installed.

These devices are meant to protect the drinking water. If there is an incident which results in the contamination of public drinking water, the owner responsible or occupant of the property can be held liable for damages.

How do I know if I have a backflow device protecting my water?

IT SHOULD LOOK LIKE ONE OF THESE

There are 3 different types usually used by irrigation companies and are shown to an approximate scale:

Dual check

(Illegal)

Dual Check
Dual Check – Not a backflow device, just a check valve

Double check

(Legal / Illegal depending on municipality)

Backflow Double Check
Proper backflow device for normal protection

Double check RPZ

(Legal)

Backflow Reduced Pressure
Proper backflow device for elevated protection
How do I know if a backflow is included in my estimate?

GET IT IN WRITING

Our estimates always include a written description and model number of every component we are installing.

Chances are if your estimate does not specifically mention a “Double Check” device (not “Dual Check“, this is very deceiving) than it is not included.

This device is expensive (~ $250.00 vs. $50.00), so it is always best to ask if you are unsure.

What is backflow?

BACKFLOW IS THE ADVERSE REVERSAL OF THE INTENDED DIRECTION OF FLOW.

There are two types of backflow;

  • back-siphonage and
  • backpressure
What is back-siphonage and how is it caused?

THINK OF A STRAW

Back-siphonage is backflow caused by a siphon, a condition where the supply pressure in a system drops to below atmospheric pressure, thus creating a vacuum within the system and allowing backflow to occur.

This condition is identical to the action of water travelling upwards through a straw that you drink from.

Causes of back-siphonage include:

  • Undersized piping (venturi effect – increased fluid velocity)
  • Burst water main
  • Draining of system piping (repair/winterization)
  • Condensation of steam (cooling)
What is backpressure and how is it caused?

THINK OF A PUMP

Backpressure is any condition where the pressure in a system becomes greater than the supply pressure feeding the system.

Causes of backpressure include:

  • Elevated piping and vessels
  • Thermal expansion (heating)
  • Pumps
What is a backflow preventer?

BACKFLOW PREVENTER

A backflow preventer is a piping arrangement or mechanical device that is designed to prevent the occurrence of backflow.

Essentially there are three categories of backflow preventers that are used.

These include the:

  • Air Gap (piping arrangement)
  • Backflow prevention assembly (testable mechanical apparatus)
  • Backflow prevention device (non-testable mechanical apparatus)