Business and Personal Service
Minimum Number of Washrooms in Business and Personal Service Occupancies
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.
The minimum water closets required in a Group D, business, and personal services occupancy, such as an office space, is based on the size of the floor area served as opposed to the actual number of people expected in the space. Refer to OBC 18.104.22.168.(1) if you don’t believe us! This requirement is specific to Group D, business, and personal services occupancies regulated by OBC. Therefore, for this calculator only the floor area is required to be entered.
A floor area of 2800 m2 would require 5 male and 5 female water closets (2,800 m2 / 14 m2/person = 200 persons (100 male and 100 female). Table 22.214.171.124 requires 5 water closets for each 100 males and 100 females).
OBC Plumbing Fixture Requirements - Business and Personal Service
(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 and lavatory is permitted to serve an occupant load that does not exceed 10 persons, refer to OBC 126.96.36.199.(2) for details.
Disclaimer and Copyright
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.