General Assembly
Minimum Number of Washrooms in Assembly Spaces
The Ontario Building Code Section 3.7 regulates the minimum number of washrooms to serve a space or number of occupants. Water closets are required to be provided for each sex assuming that the occupant load is equally divided between males and females in the floor area served unless it can be demonstrated otherwise. For general assembly spaces (based on OBC Table 3.7.4.3.A) the minimum number of water closets and lavatories required is based on the number of persons using the space. Simply input the occupant load and let the calculator do the rest!
OBC Plumbing Fixture Requirements - General Assembly
- (a) Urinals – Where only two male water closets are required, one urinal is permitted to be subsituted for one of the water closets. Where three or more water closets are required, urinals are permitted to replace up to two thirds of the required water closets.
- (b) Universal washrooms – Where more than one male and one female water closets is required, a universal washroom may be counted for male and female plumbing fixtures.
- (1) a single water closet is permitted to serve an occupant load that does not exceed 10 persons, refer to OBC 3.7.4.2.(9) for details.
The preparation of washroom calculations is the responsibility of the individual designer (architect, engineer, or other) that prepares the drawings/calculations. We strongly recommend engaging a code consultant such as Vortex Fire Consulting Inc. if you do not feel confident in preparing the calculations. The calculator provided is not intended in any way as engineering advice or services, or as a solicitation for any engineering product or service. Any results from use of these calculators may not be applicable or accurate with regard to the individual circumstances, cannot be relied upon for anything, including, without limitation, engineering/architectural designs or decisions, and should not be the basis for any action or inaction on your part.