Interpretation #8412
Published May 24, 2020
Original Request
- Code Version
- 2017
- Code
- RESIDENT
- Code Description
- Chapter
- Chapter 7 Sanitary Drainage Chapter 27 Plumbing Fixtures
- Section
- 2706.1.2
- Topic
- Standpipes
Question
Can the integrated washer surface mounted sanitary sewer and water supply box module box be mounted at the level of the top of the washer which is between 36 inches and 42 inches above finished floor if the trap weir is 16 inches below finished floor, thus enabling shutoff valves that are integral in the box to be reached in a water leak emergency, without moving the washer?
Answer Published 05/24/2020 at 8:29 AM
No, given the example described. The maximum length of the standpipe, measured from the trap weir to the top opening, cannot exceed 42 inches. If the trap weir is 16 inches below finished floor, the top of the standpipe could only reach 26 inches above finished floor (16 + 26 = 42"). The code limitation on standpipes is so that falling waste water does not gain too much velocity which might cause the trap to self-siphon. The code supersedes any manufacturer recommendations. Many plumbers avoid this situation by locating the trap above finished floor by teeing off a vertical stack. Regarding the location of the shutoff valves, Section P2903.9.3 requires valves serving plumbing fixtures and appliances to be accessible, not readily accessible, so the washer would be permitted to be moved in order to access the shutoff valves, similar to moving a refrigerator to access the icemaker shutoff valve.
Commentary
None.