The Ontario Building Code | Hydraulic Loads for Fixtures
7.4.10.2. Hydraulic Loads for Fixtures
(1) The hydraulic load from a fixture that is listed in Table 7.4.9.3. is the number of fixture unitsset forth in the Table.
(2) Except as provided in Sentence (1), the hydraulic load from a fixture that is not listed in Table 7.4.9.3. is the number of fixture units set forth in Table 7.4.10.2. for the trap of the sizethat serves the fixture.
Table 7.4.10.2.
Permitted Hydraulic Load from a Fixture Based on Size of Trap
Forming Part of Sentence 7.4.10.2.(2)
| Item | Column 1 Size of Trap, in. | Column 2 Hydraulic Load, fixture units |
| 1. | 1 ¼ | 1 |
| 2. | 1 ½ | 2 |
| 3. | 2 | 3 |
| 4. | 2 ½ | 4 |
| 5. | 3 | 5 |
| 6. | 4 | 6 |
In Plain Language
Each type of fixture is assigned a hydraulic load value, expressed in fixture units, based on the table referenced in this article, giving designers a standard way to add up total system demand.
This is a plain-language summary of the 2012/2017 Ontario Building Code text above, for general understanding only and not a substitute for the Code. Always confirm current requirements against the 2024 edition (O.Reg. 163/24) or a qualified professional before construction.