AWWA AWWA Water Distribution Systems 2

Question 1

What is the recommended minimum cover depth for water mains in frost-prone regions of the US per AWWA guidelines?

Accepted Answer

Cover depth varies by local frost depth

Answer

AWWA guidance specifies that cover depth must be sufficient to protect against local frost penetration, which varies by geographic region.

Question 2

Which AWWA standard governs polyvinyl chloride (PVC) pressure pipe for water distribution?

Accepted Answer

AWWA C900

Answer

AWWA C900 covers PVC pressure pipe and fabricated fittings used in water distribution systems with nominal diameters from 4 to 60 inches.

Question 3

What is the purpose of a pressure zone in a water distribution system?

Accepted Answer

To isolate areas with different hydraulic grade lines and maintain acceptable pressures

Answer

Pressure zones are established to keep system pressures within acceptable limits across varying elevations, using pressure-reducing valves or separate pumping.

Question 4

Per AWWA M31 (Distribution System Requirements for Fire Protection), what minimum static residual pressure is typically recommended during fire-flow events?

Accepted Answer

20 psi

Answer

AWWA M31 recommends maintaining a minimum residual pressure of 20 psi at any point in the system during design fire-flow conditions.

Question 5

What does a C-factor represent in the Hazen-Williams hydraulic formula used in distribution system modeling?

Accepted Answer

Pipe roughness/friction coefficient

Answer

The Hazen-Williams C-factor is a roughness coefficient reflecting the smoothness of a pipe's interior; higher values indicate smoother pipes with less friction loss.

(AWWA) American Water Works Association Practice Test

(AWWA) American Water Works Association Practice Test

AWWA AWWA Water Distribution Systems 2