306A Water Supply Systems 3

Question 1

What is the minimum burial depth for a water service pipe in most Canadian jurisdictions?

Accepted Answer

At or below the local frost depth

Answer

The water service pipe must be buried at or below the local frost depth to prevent freezing. In Canada, this depth varies significantly by region, from about 1.2 m in southern areas to over 2.4 m in northern regions.

Question 2

What type of copper tubing is required for above-ground water distribution within a building?

Accepted Answer

Type L or Type M

Answer

Type L or Type M copper tubing is used for above-ground water distribution. Type L is more common due to its heavier wall thickness providing better durability, while Type M is acceptable for lower-pressure residential applications.

Question 3

What is the main advantage of PEX tubing over copper for water supply distribution?

Accepted Answer

Resistance to freezing damage and flexibility for routing

Answer

PEX tubing is flexible, allowing it to bend around obstacles without fittings, and it can expand slightly without bursting if water freezes inside, making it more resistant to freeze damage than rigid copper.

Question 4

When connecting dissimilar metals in a water supply system (e.g., copper to steel), what must be used to prevent galvanic corrosion?

Accepted Answer

A dielectric union or dielectric fitting

Answer

A dielectric union separates the two dissimilar metals with an insulating material to prevent galvanic corrosion, which occurs when different metals are in direct contact in the presence of an electrolyte (water).

Question 5

What is the minimum hot water storage temperature required to prevent Legionella bacteria growth?

Accepted Answer

60°C

Answer

Hot water must be stored at a minimum of 60°C (140°F) to kill Legionella bacteria, which thrive between 20°C and 45°C. A mixing valve then tempers the water to a safe delivery temperature.

Red Seal Plumber 306A Practice Test

Red Seal Plumber 306A Practice Test

306A Water Supply Systems 3