2024 Ontario Building Code Guide: Fixture Outlet Pipe Sizes and Hydraulic Loads
Sarah's Expert Insight
OBC Compliance Specialist
"Correctly calculating hydraulic loads as per Table 7.4.9.3 is a non-negotiable step for ensuring the drainage integrity of high-end builds in Oakville and Muskoka. At empcontracting.ca Inc. your construction contractor in London, Ontario, we find that precise pipe sizing at the rough-in stage is the most effective way to prevent the chronic drainage issues often seen in older London property retrofits."
Understanding OBC Table 7.4.9.3: Plumbing Requirements for Ontario Construction
Compliance with the 2024 Building Code Compendium is essential for any renovation or new build. Table 7.4.9.3 outlines the minimum permitted size of fixture outlet pipes and the corresponding hydraulic loads (measured in fixture units) for various plumbing fixtures. Adhering to these standards ensures efficient drainage and prevents system failures in residential and commercial properties.
Minimum Nominal Pipe Sizes (NPS) and Hydraulic Loads
When planning your plumbing layout, it is critical to match the fixture with its required pipe size and load capacity. Below are key highlights from the OBC Table 7.4.9.3:
- Bathroom Groups: A standard group with a flush tank carries a hydraulic load of 6 fixture units.
- Clothes Washers: Domestic units require a load of 1.5 with an NPS 2 trap, while commercial units require a load of 2.
- Dishwashers: Domestic types generally carry a load of 1, though this is often exempt when connected to a garbage grinder or domestic sink.
- Floor Drains: These require an NPS 2 pipe and carry a load of 2 fixture units.
Detailed Fixture Specifications Table
| Fixture Type | Min Nominal Pipe Size (NPS) | Hydraulic Load (Fixture Units) |
|---|---|---|
| Autopsy Table | 1½ | 2 |
| Bathtub (with/without shower) | 1½ | 1½ |
| Bidet | 1¼ | 1 |
| Clothes Washer (Domestic) | n/a | 1½ (with NPS 2 trap) |
| Dishwasher (Domestic) | 1½ | 1 |
| Floor Drain | 2 | 2 (with NPS 2 trap) |
| Lavatory (Domestic) | 1¼ | 1 |
| Macerating Toilet System | ¾ | 4 |
| Potato Peeler | 2 | 3 |
For expert assistance in implementing these codes, trust empcontracting.ca Inc. your construction contractor in London, Ontario, to manage your plumbing and structural requirements with precision.
Disclaimer: This content is generated from the Ontario Building Code for educational purposes. Always consult with a licensed professional engineer or your local building department before starting any construction project in London, Ontario.