The Ontario Building Code | Size
7.6.3.4. Size
(1) Every water service pipe shall be sized according to the peak demand flow but shall not be less than ¾ in. in size.
(2) Except as permitted in Sentence (3), the sizeof a supply pipe that serves a fixture or device shall conform to Table 7.6.3.2.A.
(3) For fixtures listed in Table 7.6.3.2.A that have a permitted supply pipe size of ⅜ in., a connector not more than 750 mm long and not less than 6.3 mm inside diameter may be used to supply water to the fixtureor device.
(4) No water system between the point of connection with the water service pipe or the water meter and the first branch that supplies a water heater that serves more than one fixture shall be less than ¾ in. in size.
(5) Where both hot and cold water is supplied to fixturesin residential buildings containing one or two dwelling units or row houses with separate water service pipes, the water system may be sized in accordance with Table 7.6.3.4. where,
Note: On January 1, 2018, Sentence 7.6.3.4.(5) of Division B of the Regulation is amended by striking out the portion before Clause (a) and substituting the following: (See: O. Reg. 139/17, s. 56 (1))
(5) Where both hot and cold water is supplied to fixtures in residential buildings containing more than one dwelling unit, the water systemmay be sized in accordance with Table 7.6.3.4. provided,
(a) the hydraulic loads for maximum separate demands on water distribution systempiping are not less than 100% of the total hydraulic load of the fixture units given in Tables 7.6.3.2.A., 7.6.3.2.B., 7.6.3.2.C. and 7.6.3.2.D. for private use,
(b) the minimum water pressure at the entry to the building is 200 kPa, and
(c) the total maximum length of the water system is 90 m.
Table 7.6.3.4.
water pipe Sizing for Buildings Containing One or Two Dwelling Units or Row Houses with Separate Water Service Pipes
Forming Part of Sentence 7.6.3.4.(5)
Note: On January 1, 2018, the heading to Table 7.6.3.4. of Division B of the Regulation is revoked and the following substituted: (See: O. Reg. 139/17, s. 56 (2))
Table 7.6.3.4.
Water Pipe Sizing for Buildings Containing More Than One Dwelling Unit
Forming Part of Sentence 7.6.3.4.(5)
| Item | Column 1 | Column 2 | Column 3 |
|
| Size of Water Pipe, in. | Water Velocity m/s(1) | |
|
|
| 2.4 | 1.5 |
|
|
| Hydraulic Load, fixture units | |
| 1. | 1/2 | 7 | 4 |
| 2. | 3/4 | 16 | 9 |
| 3. | 1 | 31 | 18 |
| 4. | 1-1/4 | 57 | 30 |
Notes to Table 7.6.3.4.:
(1) Table 7.6.3.4. is not intended to limit water velocities that are permitted by Sentence 7.6.3.5.(1).
Note: On January 1, 2018, Article 7.6.3.4. of Division B of the Regulation is amended by adding the following Sentence: (See: O. Reg. 139/17, s. 56 (3))
(6) Where both hot and cold water is supplied to fixtures in a house containing only one dwelling unit, the water service pipe is permitted to be a minimum of ¾ in. in size provided,
(a) a minimum ¾ in. water supply piping located in the basement or lower level is extended to the base of every hot and cold riserthat serves a maximum of one bathroom group and to the last water supply branch serving any basement bathroom group, fixture supply or hose bibb, and
(b) the total hydraulic load is not more than 26 fixture units, using the values given in Table 7.6.3.2.A.