Drainage
Sanitary Drainage Design Guide
Sanitary drainage system design involves sizing waste pipes using Drainage Fixture Units (DFU), selecting appropriate slopes, and ensuring venting adequacy.
Introduction
Sanitary drainage systems carry wastewater from fixtures to the building drain and sewer. Proper sizing ensures pipes can carry expected flow without backing up, while proper slope ensures self-cleaning velocity. Plumbing Booster's Drainage System module automates sanitary drainage design for one-pipe and two-pipe systems.
Methodology
1. **Assign DFU** - Each fixture has a Drainage Fixture Unit value from code tables.
2. **Sum DFU per pipe segment** - Total DFU for each branch, stack, and building drain.
3. **Select pipe size** - Use the code's drainage sizing table to find minimum pipe size for total DFU.
4. **Verify slope** - 1/4" per foot for pipes <3", 1/8" per foot for pipes >=3".
5. **Size vent piping** - Vents sized to maintain atmospheric pressure using separate code tables.
6. **Check maximum length** - Code tables specify maximum developed length per pipe size.
One-Pipe vs Two-Pipe Systems
**One-pipe**: A single stack serves as both soil and waste stack. Simpler design, fewer penetrations.
**Two-pipe**: Separate soil stack (water closets/urinals) and waste stack (other fixtures). Used when code requires separation or building layout favors it.
Plumbing Booster supports both configurations in the Drainage System Structure page.
Code References
**IPC**: Table 710.1 (max unit loading/length), Section 705 (slope), Section 906 (vent sizing).
**UPC**: Table 703.2 (max unit loading/length), Appendix C Table C304.2 (building drains), C304.3 (branches/stacks).
How Plumbing Booster Automates It
Configure floors and drainage areas in System Structure. Add fixtures - DFU is auto-calculated. Assign to stacks (one-pipe or two-pipe). The software sizes branches, stacks, and building drains, checks slope compliance, generates a Drainage Riser Diagram, and exports PDF reports.
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Drainage Pipe Sizing Reference
Complete reference for drainage pipe sizing using IPC Table 710.1 and UPC Table 703.2, including slope requirements and maximum length limitations.
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