Vancouver staff report on single-stair buildings up to six storeys

If Seattle can do it, why can't we?

Bryn Davidson’s two-stair apartment building

Potential to Update the Vancouver Building Bylaw to Enable Single Egress Stairs. Memo from Chief Building Officer. On the agenda for the February 26 meeting of the Standing Committee on Policy and Strategic Priorities.

Summary: Vancouver city staff are recommending that city council not go ahead with allowing small six-storey buildings with a single stair, as Seattle has allowed since 1977. They say that the Seattle fire department is better than Vancouver’s, but they don’t say what the difference is.

Point access blocks vs. hotel-style layouts

There’s a basic difference between European-style and North-American-style apartment layouts. In North America, an apartment building (even low-rise) requires two exits, and it’s typical to use a hotel-style layout, with apartments on either side of a long hallway.

In Europe, it’s typical to have two to four apartments laid out around a central stairway, allowing more efficient use of space, more flexibility, and the ability to keep bedrooms away from the noisy side of the building.

Apartment buildings in Montreal also use a European-style layout: Montreal has its own building code, and it allows the second exit to be a narrow external staircase, something like a fire escape. Vancouver also has its own building code and in theory could do something similar, but I don’t know how likely that is.

Seattle has allowed apartment buildings up to six storeys with a single central staircase since 1977, making it easier to build an apartment building on a small lot.

Here’s an example of a European-style “point access block” layout with four apartments built around a central stairway, from a report by Larch Labs. It’s quite efficient, with only 7% of the “floor plate” needed for circulation as opposed to living space. It can also be quite compact.

On a busy street, typically you'd have the stairs at the front of the building and the bedrooms on the quieter side.

In a typical North American apartment building, the hallway takes up a lot of space, so you need a deeper building to spread the cost over a larger area. This particular diagram shows 12 apartments on either side of a hallway. Circulation takes up 13% of the floor plate. And the building itself has to be larger, which requires assembling more land.

Except for the corner units, most of the apartments tend to be long and narrow (like a bowling alley), with windows only on one side. Adding another bedroom with a window is quite expensive: there’s a lot of space between the window and the hallway that needs to be filled.

On a busy street, half the apartments are going to be facing the street.

From a fire safety point of view, you’re going to have longer travel distances from an apartment to the nearest stair.

Vancouver city staff recommends leaving things the way they are

In September 2024, the BC government updated the BC Building Code to allow apartment buildings up to six storeys with a single central staircase, with additional fire safety measures, after commissioning a report from Jensen Hughes (a safety consulting firm).

In October 2024, Sarah Kirby-Yung made a motion asking city staff to report back. It passed unanimously.

A. THAT Council direct staff to report back in Q4 2024 on the potential to and required changes needed to align the Vancouver Building By-law with the BC Building Code, in order to permit single egress stairs in low & mid-rise buildings in buildings up to six (6) stories to enable larger layouts and more multi-bedroom apartment options for families and people who need them.

B. THAT the report back be guided by advice of Vancouver Fire & Rescue Services and consideration of VFRS concerns, or recommendations with respect to the identification or potential inclusion of supporting life safety and firefighting measures.

Now staff has reported back, giving city council two options: either leave things the way they are (A), or direct staff to make a specific proposal (B).

Recommendation

A. THAT Council decline to adopt of the Provincial “Single Egress Stair” provisions enacted as Revision 3 to the 2024 BC Building Code, on account that the proposed features are not well suited to the Vancouver context.

FURTHER THAT Council direct the Chief Building Official, in consultation with the Fire Chief, to further investigate and report back with recommendations to safely densify sites across the City, through the adoption of space-efficient egress in small residential buildings.

Alternative Consideration

B. THAT as an alternative to Recommendation A above, Council direct the Chief Building Official, in consultation with the Fire Chief, to report back with proposed alterations to Building By-law to adopt, with modifications, the Provincial Single Egress Stair provisions including additional mitigations as may be warranted in the Vancouver context.

What’s the reasoning?

There are other jurisdictions around the world which do allow single egress stair designs exceeding 2 storeys. Yet, research by the National Fire Protection Association and others have pointed to differences in data collection, regional design and construction materials choices, and other factors that can lead to different conclusions when interpreting the available data.

Even when comparing with the often referenced City of Seattle, there are local differences; it is notable that the Seattle fire department does not support broader expansion of the single egress stair provisions and has identified the crucial nature of a rapid fire department response, and that substantive fire fighting capabilities, more than almost every other fire department in North America has, including Vancouver, are needed to make SES work.

Seattle Fire Department

The NFPA ran a symposium on single-stair buildings in September 2024. There was a presentation from Karen Grove of the Seattle fire department. The details of the fire safety requirements are quite interesting.

The code option of allowing a single very well protected stair/egress path, in lieu of requiring two stairs, was first adopted for existing buildings in Seattle more than 50 years ago. It provided retroactive requirements for older hotels and apartments. After devastating fires occurred in the early 1970s in buildings that had open stairways, Seattle required existing hotels and apartments to have two fully enclosed stairs. The historical fires that led to these requirements were the Ozark Hotel fire and the Seventh Ave Apartment fire.

The Ozark Hotel had two open stairs, no sprinklers, and was constructed of wood. The fire was caused by arson, which targeted the stairs. More than 100 firefighters responded and most occupants that were trapped were on upper floors. The fire killed 21 people and injured 13. This led to major changes in the Seattle Building Code. Within three months, the Ozark ordinance was passed (June 1970), which required all hotels and apartments with four stories or more to have solid core dwelling doors, two enclosed stairs with self-closing doors, 1-hour fire resistive construction for stairs. Alternatively, buildings that provided sprinkler protection for the corridor and stairwell were allowed a single stair.

In 1971, the Seventh Ave Apartment fire happened. This building included open stairwells, the fire started in the basement, and the building was three stories, so not subject to the Ozark ordinance. The fire moved quickly and killed 12 people. A new ordinance was passed that extended the Ozark provisions to all hotels and apartment buildings. In addition to the requirement for two enclosed stairs, and solid core doors, this new ordinance included an exemption to allow one stair, if the stair and corridors were protected by sprinklers and made of certain fire-resistant construction.

The Seattle experience in the 1970s gave SFD experience with the option of allowing a single very reliable stair in a sprinklered building, as an alternative to two enclosed stairs. In the late 1970s, Seattle’s Building Official and Fire Marshal for the first time introduced this exemption into the code for new construction: it allowed one stair in apartment buildings up to six stories, if the egress path, including the stair, is very reliable. The building needs to be a minimum of 1-hour construction, sprinklered, and there is a maximum of four dwelling units per floor. Other occupancies cannot “communicate with” the Group R portion of building or the stair being used by those in the Group R dwellings. The provision also introduced early use of stairwell and elevator shaft pressurization.

Grove did say that Seattle has very quick response times and good hydrant infrastructure.

She noted that this is important context for any department evaluating the single stair proposal because it is vital to understand what this change means for fire department operations. Seattle’s code provisions may not be appropriate for all fire departments if they do not have the same resources and capabilities.

I’m curious: when Vancouver city staff say that the Vancouver fire department doesn’t have the same capabilities as the Seattle fire department, what are they referring to?

Proposal from the Center for Building in North America

Stephen Smith of the Center for Building in North America presented a proposed change to the so-called International Building Code at the NFPA symposium. Proposed change to the International Building Code, second revision, with discussion and research.

One of the concerns raised by the Vancouver staff report:

Hoses need to be connected to the standpipes in the stair, which means that the doors between the stair and the fire floor must be held open, allowing smoke to spill into the exit stairway which could lead to the single stair becoming untenable. There is no alternative stair to allow for evacuation of the residents who are slow to respond or who have mobility challenges. The SES provisions attempted to mitigate the potential of fire and smoke spread into the stairway by requiring pressurization of the stairs, or constructing vestibules on each floor. However, the SES provisions did not take into account the necessity of opening exit stair doors to extend hose onto the fire floor, thereby negating the effects of both the pressurization and the vestibule.

From Stephen Smith’s proposal:

While our proposal strictly limits the size of floors and corridors, the main body of the IBC allows much longer corridors – up to 500 occupants can share a floor with just two stairs, with exit access travel distances of up to 250 feet per Table 1017.2 for R-2 occupancies. Common paths of travel can be up to 125 feet in length.

Compared to the main body of the current IBC, our proposal significantly limits the number of occupants that could be exposed to the hazardous exit access conditions described by Dutch researchers if, in the event of a fire sprinkler system failure, an apartment door is held open and smoke compromises a common corridor, either because of hose operations or the failure of a self-closing door.

In other words, requiring smaller buildings reduces the number of occupants exposed to the potential hazard, compared to effectively requiring larger buildings.

The NFPA debate

From the NFPA symposium report:

Two distinct perspectives quickly emerged during the symposium. First, those who saw single exit buildings as currently permissible with allowances limiting their height saw the proposal as simply expanding those limits to six stories with some additional proposed fire and life safety features.

Second, the view that currently all six-story buildings require at least two exits saw the proposal as simply removing the second exit.

Summary of the key concerns, from a fire safety perspective:

1. The single exit stair results in the means of egress being susceptible to a single point of failure.

2. The types of allowable construction for single exit stair buildings.

3. Impact of a single exit stair on firefighter operational capabilities.

4. Occupants evacuating while firefighters are going up to attack the fire.

5. Hazards arising post occupancy.

Again, I’m not sure what would be different here between Seattle and Vancouver.

A note regarding post-occupancy hazards:

There are a number of hazards that can arise post occupancy of a building ranging from the inspection, testing, and maintenance of fire protection systems, to occupants storing goods in the corridor, to impacts of building rehabilitation. It is important to note that many of these issues are not specific to single exit stair buildings. When considering this concern, it is important to consider which issues are truly unique to single exit stair apartment buildings so that this proposed design allowance is not holding them to a different level of safety than other buildings. For example, challenges around lithium-ion battery fires, which was a common concern during the symposium, are not unique to single exit stair buildings.

More

• The Seattle Special: A US City’s Unique Approach to Small Infill Lots. Sean Jursnick, December 2024.

• The Second Egress: Building a Code Change. By Conrad Speckert.

• City of Vancouver staff oppose single-staircase residential buildings due to safety risks. Kenneth Chan, Daily Hive.

• Vancouver City Staff Opposing Adoption Of Single Egress Building Code Change. Howard Chai, Storeys.

• 'Better call Saul' in Vancouver: City's top building official on demolitions and the fight for safe housing. Mike Howell, Business in Vancouver. A profile of Saul Schwebs, Vancouver’s chief building official. He’s seen a lot of poorly maintained buildings, and because of Vancouver’s housing shortage, he’s worried about people living in them anyway.

• One thing I was curious about: Sweden allows single-stair buildings up to 16 storeys. A conference paper suggests that a more reasonable limit would be seven storeys. Redefining fire safety in Swedish high-rise buildings, Fredrik Nystedt and Tomas Rantatalo, April 2008. “The Swedish building code currently considers buildings with more than 16 stories as high-rises that require special attention by the design team. This is not in line with the design challenges identified in the previous sections, as external rescue operations are considered unavailable in buildings higher than seven stories. In Sweden a reasonable definition of a high-rise building would be a tall building with eight or more stories.”

• Previously: European flats, BC considering single stair, BC allows single stair, hotel-style layout, single-lot single-stair buildings