306A Drainage and Venting Systems 4

Question 1

What causes self-siphonage in a plumbing trap?

Accepted Answer

The momentum of water leaving the fixture creates a vacuum that pulls the trap seal out

Answer

Excessive water pressure

Answer

Tree root infiltration

Answer

A defective trap weir

Question 2

What is 'induced siphonage' in a drainage system?

Accepted Answer

Trap seal loss caused by the discharge of another fixture on the same branch

Answer

Siphonage caused by the fixture's own discharge

Answer

Siphonage caused by municipal sewer surcharging

Answer

Intentional siphoning for drainage purposes

Question 3

What is the fixture unit rating for a shower stall in a residential building?

Accepted Answer

2 fixture units

Answer

1 fixture unit

Answer

3 fixture units

Answer

4 fixture units

Question 4

What is the minimum pipe size for a building storm drain?

Accepted Answer

4 inch

Answer

2 inch

Answer

3 inch

Answer

6 inch

Question 5

What determines the size of a roof drain leader (rain water leader)?

Accepted Answer

The area of roof being drained and the local rainfall intensity

Answer

The height of the building only

Answer

The pipe material used

Answer

The number of vent stacks in the building

Question 6

Why should storm drainage never be connected to the sanitary sewer system?

Accepted Answer

Rainwater would dilute the sewage treatment process and surcharge the sanitary system during storms

Answer

Storm water is too dirty for the sanitary system

Answer

It is impossible to connect them due to pipe sizes

Answer

Storm water is always cleaner than sanitary waste