Tag: egress

• BC now allows single egress stair buildings up to 6 storeys

  The province of British Columbia made the following announcement this week:

  The Province has updated the BCBC to remove the [building] code requirement for a second egress, or exit, stairwell per floor in buildings up to six storeys. This change will make it possible to build housing projects on smaller lots and in different configurations, while allowing more flexibility for multi-bedroom apartments, more density within areas of transit-oriented developments and the potential to improve energy efficiency in buildings. Previously, the BCBC called for at least two egress stairwells in buildings three storeys and higher.

  This is meaningful progress. And BC is the leading the way in Canada. But from a global perspective, we are not leading the way. This is us catching up.

  As part of this building code change, the province commissioned a report on single egress stair building designs. In this report, they looked at various jurisdictions from around the world:

  Their non-exhaustive findings:

  There are at least 30 jurisdictions with SES building design requirements that permit midrise buildings with a building height of at least 5 or 6 storeys. In addition, the Center for Building in North America (www.centerforbuilding.org) reports that 8 US states have passed legislation into law, or are reviewing possible options for doing so, to allow larger SES buildings when their Building Code is next revised. In most cases these revisions are intended to allow SES buildings of up to 6 storeys.

  For example, Seattle already allows up to 6 storeys. Belgium, New Zealand, and Australia allow up to 9 storeys (driven by a maximum height in meters). And Finland allows up to 18 storeys, according to the report.

  Though keep in mind that building codes are complicated and often have frustrating gray areas. There may be other requirements that need to be met in order to achieve these heights.

  It’s great to see BC making these moves. Now watch for other provinces to follow suit.

  2024.08.31

• Open-air corridors and exterior exit stairs

  Montreal is, in many ways, a city of winding exterior stairs. If you’ve been there, then you know. The city is overwhelmingly a city of low-rise apartments (less than five storeys). And with these, comes lots of exterior circulation. But this tradition doesn’t just apply to older buildings. Here is a contemporary tall-building example which follows a similar approach.

  Designed by MSDL Architects, the project, called The Laurent & Clark, consists of two tower volumes. They read as two separate towers, but they’re connected and share egress paths. On the east side is a conventional “scissor stair” tucked behind two elevators. And on the other end, connected by an open-air corridor, is an exterior exit stair that runs all the way up the tower.

  Here is a circulation diagram via Azure:

  

  This is novel (at least in this part of the world). The suites in the west tower are all dual aspect; meaning, they have windows on both ends.

  They also have direct elevator access (see cores above), which means a lot less non-revenue generating circulation space. I mean, if you think about it, the open-air corridor on the north side of the west tower is akin to building a simple balcony. Extend the slab and add a guard rail. And so you could argue that this portion of the building has a near 100% efficiency factor.

  However, the downside is that you need more elevators. Here, it looks like they have 6 for their 356 suites. That’s an overall ratio of just under 60 suites per elevator, which is lower (i.e. better) than what you’d typically find in a conventional tower. The crude rule of thumb is 1 elevator for every 100 suites. That said, these direct-access suites would be premium.

  But perhaps the most important takeaway is this: If cold and snowy Montreal is cool with open-air corridors and exterior exit stairs, then maybe your city should be as well.

  2024.04.25