Self-Test D-3.2 Functions of Pipes in Storm Drainage Systems

Complete Self-Test D-3.2 and check your answers.

1. What is the function of the dome installed over the drain opening in a flat roof drain?
   1. Acts as a warning device for a trip hazard for anyone on the roof
   2. Acts as a roof drain locating device when the roof is flooded due to a drain blockage
   3. Prevents debris from entering the drainage system from the roof
   4. Prevents winter ice and snow buildup on the drain inlet

    

2. A horizontal leader installed in conjunction with a siphonic roof drain is designed to flow at what capacity?
   1. 25% full
   2. 50% full
   3. 75% full
   4. 100% full

    

3. A flow-control roof drain system requires special building design considerations. Which of the following would be most important?
   1. Slope of the roof
   2. Structural design of the roof
   3. Height of the parapet wall
   4. Area of the roof

    

4. Other than acting as a stormwater collection device for a paved area, what other function does a catch basin serve for the storm drainage system?
   1. Traps debris that might otherwise enter the drainage system
   2. Discourages the entrance of rodents into the storm drainage system
   3. Allows all larger flows to be drained from the system without increasing the pipe size

    

5. What is the purpose of a CSO in regard to a municipal combined sewer system?
   1. Acts as a collection reservoir to detain untreated sewage until it can be properly treated at a sewage treatment plant
   2. Acts as a diverting device so the stormwater flow in the combined system is diverted around the sewage treatment plant without being treated
   3. Acts as an overflow mechanism so the combined drainage flow is allowed to flow to a discharge point in its raw form without treatment
   4. Acts as a metering chamber at the point of entry and allow only as much flow into the combined system as the sewage treatment plant can accommodate

    

Answer Key: Self-Test D-3.2 is on the next page.