Designing Mid-Rise Residential Buildings with a Single Exit Stair – Good or Bad Idea?
Suzanne Alfano Executive Director, CFAA
In recent years, there have been pushes across Canada and the United States by special interest groups to allow new residential buildings up to six stories in height with only a single exit stairwell. These proposals have circumvented the open and transparent national codes and standards development processes that help ensure fire and life safety protection for residents, visitors, and first responders.
To increase the allowable height of residential buildings to six stories with a single exit stairwell raises concerns such as occupant and firefighter safety in the event of a fire emergency; housing affordability because of the extra square footage in building design required to include a second stairwell; and alternative solutions to building codes that some local jurisdictions may accept.
Currently the National Building Code of Canada requirement limits a two-story maximum for a single exit stairwell residential building design. A proposal to accept a six-story single exit stair design has been in the National Building Code of Canada’s process for several years without a resolution. It was originally proposed in 2022, though not given consideration because the focus was on other priorities related to energy efficiency of buildings at the time. In late 2024 a NRC consultation group began reviewing the single stair issue.
In British Columbia, a proposal to permit up to six-story residential building design with a single exit stair was officially approved and incorporated into the BC Building Code in August 2024. The proposal had a very brief stakeholder consultation period and has been criticized by some groups as a hasty decision that reduces safety for building occupants and firefighters should a fire emergency occur. Typically, when there is a fire in a mid-rise building firefighters use one exit staircase for personnel to fight the fire, often referred to as the “dirty stairwell.” The second exit stairwell is used to evacuate occupants. The use of elevators is not always possible during a fire emergency. Critics argue that by forcing occupants and firefighters to use the same single exit stairwell in the event of a fire emergency will compromise the safety of all, which I fully agree with.
In some US cities, three- and four-story buildings are permitted with a single exit stairwell, though there are several factors that are considered by Authorities Having Jurisdiction (AHJs) before allowing this variation in building design. In Europe, some buildings are designed with many more stories, and a single exit stairwell is permitted.
Critical stairwell for firefighters
The stairwell is many things to firefighters. It is how they get to the fire floor. It is, many times, where the water source is located and where the fire attack will be initiated. It can be a staging area for the backup crew or second line. It is also a place of refuge when things go bad. Simply retreating and closing the door can provide the protection a crew needs to escape a dire situation or restart the attack after being overtaken by rapidly changing fire conditions. The stairwell is a remote command post for the division officer or attack team lead officer. It is where firefighters set their discharge pressure prior to entering a hostile environment.
During high-rise and mid-rise fire operations, the success of operations hinges on the stairwell.
In September 2024, recognizing that the single exit stair debate was ramping up, NFPA hosted an international symposium focused on the issue at NFPA Headquarters in Quincy, Massachusetts. The symposium included representatives from the U.S., Canada, the United Kingdom, and Australia. The goal of the symposium was to bring together proponents and opponents of allowing taller apartment buildings with a single exit stairwell for a detailed discussion.
Below is a link to an informative NFPA article on the single exit stairwell issue and a link to their Symposium Report.
CFAA and the Fire Protection Association of British Columbia are co-hosting our Annual BC FIRECON Conference in Burnaby, BC on September 25 and 26, 2025. I will be moderating a panel discussion on the single exit stair issue where we will have three great speakers with diverse opinions on this topic presenting on the morning of Friday, September 26. Please join us either in-person or live online. To purchase tickets, visit the BC FIRECON website at www.bcfirecon.ca.
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