Chapter 5 - General Backflow Preventer install Requirements

Question 1

Complete the following statement “all backflow preventers shall be installed…”

Answer 1

in a readily accessible location a/ adequate space to facilitate maintenance + testing

Question 2

As a general rule, How much space should be provided for backflow preventers?

Answer 2

Above: 12”
In front: 30”
Behind: 3/4”

Question 3

What is the max centerline height that any in-line testable backflow preventer may be installed above the flow or a permanent fixed platform?

Answer 3

Anything above 60” (5’)

Question 4

Why is an RP the only in-line testable assembly which has a requirement for clearance below the device?

Answer 4

In order the the RV to be accessible for maintenance or repair

Question 5

All backflow preventers w/ an air inlet, air vent or relief valve port are not permitted to be installed where?

Answer 5

Below the level in a pit, vault or trench –> vulnerable to flooding

Question 6

What can be done if a backflow preventer needs to be installed in a waterline containing temps which exceed the manufacturer’s recommended max temps?

Answer 6

Get a higher rated backflow preventer

Question 7

If a backflow preventer is installed on the upstream side of a hot water tank, what may have to be considered?

Answer 7

Thermal expansion tank or thermal expansion RV

Question 8

What can be installed on the piping downstream of an RP to lessen the effects of water hammer?

Answer 8

Water hammer arresters
Surge protectors
-slowly opening or closing any valve

Question 9

What should be done to the waterline prior to installing any backflow preventer?

Answer 9

Flush the lines –> decreases damages to internal compounds

Question 10

What procedure must be take if a strainer is to be installed upstream of a backflow preventer or a fire system?

Answer 10

Must be approved by AHJ or insurance underwriters

Question 11

Installations that require uninterrupted 24 - hour service require what to be installed?

Answer 11

Parallel installations

Question 12

Can you have a bypass line w/ a lower level of protection or smaller size installed around a backflow preventer for use during testing / maintenance of the primary backflow preventer?

Answer 12

No , should be the same size / combined capacity to maintain the flow rate of the service pipe