Typology
5-Storey Mixed-Use Building

Occupancy
Group C, 14 Dwelling Units

Classification
2024 Ontario Building Code, Part 3

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Status: Submitted Alternative Solution (October 2024), Denied by City of Hamilton (February 2025)

An alternative solution was submitted to the City of Hamilton for this five-storey apartment building proposed to be served by a single exit stair. There are three dwelling units on each of the upper floors, except that the fifth floor contains two dwelling units and a small rooftop patio, laundry and amenity room. In total, the five-storey building design provides 14 dwelling units.

This undeveloped site is quite small at 12.3m wide by 23m deep. However, the site zoning is C5 (mixed-use medium-density) which allows for buildings of up to 6 storeys. The property is also less than a block away from one of Hamilton’s busiest intersections and has access to transit options for accessing nearby college and university campuses. A future light-rail transit stop is planned for within steps of the site.

The design team explored several options to maximize floor area efficiency, including a scissor stair. The team also prepared a building design with a single exit stair in collaboration with LMDG Building Code Consultants, based upon the technical conditions for SES (single exit stair) building design in the British Columbia Building Code, as the basis for an alternative solution to the Ontario Building Code. The result is a building design having an additional bedroom on each upper storey and 16% more usable floor area.

February 2025 Status Update: The requested alternative solution was denied by the City of Hamilton, with correspondence that if the proposed building were reduced from 5 storeys to 4 storeys, it would be accepted. The applicant can appeal the decision of the Building Division by applying to the Ontario Building Code Commission.

A summary of the single exit stair alternative solution is provided below to describe the conditions for the proposed building . The requirement that will not be met by the design are OBC 3.4.2.1(1) and 3.3.4.4.(6)(a). In lieu of complying with these prescriptive requirements, an alternative solution with mitigating measures addressing the Objectives and Functional Statements attributed to these requirements is proposed.

The intent of the requirement of Sentence 3.4.2.1.(1) to have a minimum of two exits is:

1. to limit the probability that persons will not have a choice of an alternative exit in the event that one exit is blocked or obstructed in an emergency situation, which could lead to delays in the evacuation or movement of persons to a safe place, which could lead to harm to persons, and

2. to limit the probability that emergency responders will not have a choice of an alternative exit in the event that one exit is blocked or obstructed in an emergency situation, which could lead to emergency responders being delayed in gaining access to a floor area, which could lead to delays or ineffectiveness in emergency response operations, which could lead to:

a. delays in the evacuation or movement of persons to a safe place, which could lead to harm to persons, or

b. the spread of fire, which could lead to harm to persons or damage to the building.

The intent of the requirement of Clause 3.3.4.4.(6)(a) to provide a second and separate means of egress where an egress door from the unit opens onto a public corridor serving more than one suite and served by a single exit is to exempt egress facilities serving a dwelling unit from the requirements of Sentences 3.3.1.3.(8) and (9), and 3.3.1.9.(7) which would otherwise: 

1. require a doorway to the exterior, a public corridor or an exterior passageway, or

2. prohibit a dead-end corridor that is longer than 6 m.

These requirements are premised upon the basis that there is a second means of egress from the dwelling unit available if the route through a means of egress leading to the exit is impeded, blocked, or untenable. The dead-end corridor requirement is to limit the probability that persons will not have the choice of an alternative egress route in the case where one route is blocked or obstructed in an emergency situation, which could lead to delays in the evacuation or movement of persons to a safe place, which could lead to harm to persons.



The Alternative Solution proposes that the design will conform to the measures outlined in the ‘Technical Solutions for Single Exit Stair Building Designs’ as part of the British Columbia Building Code 2024 Revision 3.

The following sections outline the measures proposed to address the provision of a single exit from Level 2 through 5 of the building:

2.3.1 Fire Protection and Life Safety Systems

• The building will be fully sprinklered with sprinkler protection provided for balconies and decks.
• The building will be provided with a fire alarm system and adequate water supply for firefighting will be demonstrated.
• If fans are required to limit smoke movement, a 2-hour emergency power supply will be provided.

2.3.2 Building Configuration

• The building will be not more than 6 storeys in building height.
• The building will be not more than 18 m high measured between the floor of the first storey and the uppermost floor level.
• A maximum of 4 dwelling units will be provided per floor.
• The maximum occupant load served by the stair will not exceed 24 persons per floor.
• The travel distance from any part of the floor area to an exit will not exceed 25 m.
• The travel distance from the door of a suite served by a single exit to the exit will not exceed 6 m.

2.3.3 Exit Facility Design

• The exit stair will be separated from the remainder of the building by a 2-hour rated fire separation.
• A minimum 1500 mm exit width will be provided for the exit facility.
• The exit stair will discharge directly to the exterior.
• The discharge from the exit stair will be located not less than 3 m and not more than 15 m from the closest portion of the access route required for fire department use, measured horizontally from the face of the building.
• Signage will be provided within the exit clearly stating storage within the exit is prohibited.
• As the building will be more than 4 storeys in building height, the building will be designed to limit smoke movement in accordance with BCBC Article 3.2.10.3.

2.3.4 Suite Doors

• Electromagnetic hold-open devices are proposed to be provided for all suite entry doors.
• Suite entry doors opening into the public corridor providing access to the single exit stair will have a minimum ¾-hour fire-protection rating.