CSLB C-36 Plumbing ContractorPlanning and EstimatingHard
A plumbing contractor is reviewing a commercial blueprint that specifies a 6-inch diameter building sewer connecting to the public sewer main. The blueprint indicates the building sewer will serve a total of 150 drainage fixture units (DFU). According to the Uniform Plumbing Code (UPC), what is the maximum DFU capacity for a 6-inch building sewer with a slope of 1/8 inch per foot?
- A1600 DFU
- B216 DFU
- C500 DFU
- D700 DFU
Show answer & explanationAnswer & explanation
Correct answer: D. 700 DFU
According to UPC Table 703.2 (or equivalent), a 6-inch building sewer with a slope of 1/8 inch per foot has a maximum drainage fixture unit (DFU) capacity of 700. The proposed 150 DFU is well within this limit.
Why the other options are wrong
- A. 1600 DFU is the maximum for an 8-inch building sewer at 1/8 inch per foot slope.
- B. 216 DFU is the maximum for a 4-inch building sewer at 1/8 inch per foot slope.
- C. 500 DFU is the maximum for a 5-inch building sewer at 1/8 inch per foot slope.
Building Sewer DFU Capacity (UPC)
The maximum number of drainage fixture units (DFU) that a building sewer of a specific diameter and slope can accommodate according to the Uniform Plumbing Code (UPC).
- DFU values are assigned to plumbing fixtures based on their probable discharge into the drainage system.
- Building sewer capacity is determined by pipe diameter and slope.
- UPC Table 703.2 (or similar) provides these capacity limits.
- Proper sizing ensures adequate flow and prevents overloading and blockages.
Memory trick: Diameter and slope dictate the flow's fate.