Unit 331 / 10 Requirements for backflow protection (mechanical)

Multiple Choice

Why is backflow protection important in plumbing systems, especially in cold water system planning and design?

• To prevent contamination of potable water

• To increase water pressure

• To reduce water usage

• To improve water taste

Multiple Choice

Which type of backflow prevention device is suitable for protection against both back-pressure and back-siphonage up to fluid category 4?

• BA (Verifiable backflow preventer with reduced pressure zone)

• CA (Non-verifiable disconnector)

• DB (Pipe interrupter)

• EA/EB (Single check valves)

Multiple Select

Which of the following statements about a Type BA (RPZ) valve are correct?

• It is suitable for protection against fluid category 4 for both back-pressure and back-siphonage.

• It incorporates a differential relief valve and two check valves.

• It is a non-verifiable device.

• It can be checked via test points for correct operation.

Fill in the Blank

A type CA backflow preventer is commonly used as a permanent connection between a sealed central heating system and the water undertaker’s ___ water supply.

Multiple Choice

What is the main purpose of the outer vents in a DB pipe interrupter?

• To allow water to escape during normal flow

• To prevent back siphonage by opening to atmosphere during pressure loss

• To increase water pressure

• To filter impurities from water

Multiple Select

Which of the following statements about the EC verifiable double check valve are correct?

• It is used in domestic installations on garden hose union bib taps.

• It must be fitted to the cold water inlet, not the sealed heating connection.

• It has two test points to verify correct operation.

• It is suitable for protection against fluid category 2 only.

Multiple Choice

What is the main difference between an EA/EB verifiable single check valve and an EC verifiable double check valve?

• The EC valve has two spring loaded valves and two test points, while the EA/EB valve has one of each.

• The EA/EB valve is used for higher fluid categories than the EC valve.

• The EC valve is not verifiable, while the EA/EB valve is.

• The EA/EB valve is only used for hot water systems.

Fill in the Blank

The ED non-verifiable double check valve contains two ___ loaded valves.

Multiple Choice

What is the primary function of the HA hose union backflow protector?

• To prevent backflow by using a rubber membrane and stainless steel spring.

• To increase water pressure in the hose.

• To filter debris from the water supply.

• To regulate water temperature.

Multiple Choice

According to the Water Supply Regulations, why should mechanical backflow prevention devices be fitted within the envelope of the building?

• To prevent damage by freezing.

• To increase water flow.

• To reduce installation costs.

• To improve water taste.

Fill in the Blank

A self-closing handheld garden spray should be fitted with a ___ mechanism at the outlet of the hose.

Multiple Choice

What is the essential feature of a self-closing handheld garden spray?

• It should be fitted with a self-closing mechanism at the outlet of the hose.

• It should have a long hose for extended reach.

• It must be made of metal only.

• It should have multiple spray patterns.

Multiple Choice

What is the main function of the HC diverter in a bath shower mixer?

• It prevents backflow by automatically returning the bath outlet open to the atmosphere when a vacuum occurs.

• It increases water pressure in the shower.

• It mixes hot and cold water for the shower.

• It filters impurities from the water.

Multiple Select

Which of the following are correct about devices that prevent backflow in plumbing systems?

• HC diverters create a mechanical backflow prevention device.

• Self-closing mechanisms in garden sprays prevent backflow.

• All hand-held hoses must have a vacuum breaker.

• CA devices are used for permanent connections between cold water supply and sealed heating systems.

Multiple Choice

The installation of an RPZ valve downstream of the undertaker’s stop valve will prevent which category of risk fluid from entering the undertaker’s mains?

• Category 2

• Category 3

• Category 4

• Category 5

Multiple Choice

According to the explanation, what is the correct placement of an RPZ valve to protect a fluid category 1 water supply from contamination?

• Upstream of the undertaker’s stop valve

• Downstream of the undertaker’s stop valve

• At the water meter

• At the point of use