A couple of weeks ago on our LinkedIn initiative #TwoCentsTuesday, we asked you to rank the following features of a door in order of importance: air tightness, water tightness, and wheelchair accessibility. So, why did we ask you to rank them? Because unfortunately, you can’t have it all. When it comes to door performance, having a product that allows for wheelchair accessibility will impact the air and water tightness of the door and vice versa. Here’s why.
A lot has changed with doors in the last ten years. We saw NAFS come into effect around 2012, which significantly increased performance expectations. This includes air tightness, water tightness, structural performance, and many other requirements. This new standard was different from what door pre-hangers at the time were used to, resulting in many changes to the industry. We’re now seeing fewer traditional single-point hardware doors being used, and more multipoint, triple weather-stripped, PVC-framed doors in their place.
The Universal Door
The new expectations impacted doors and their features, with one key change being the hardware. For a door to achieve its air and water tightness, uniform gasket compression is critical. This calls for multipoint hardware, so the door can lock in numerous locations as opposed to a single deadbolt location and the force required to “cam” the lock in to compress the gasket is increased.
Something else has happened while the industry has been changing: the demand for wireless App-based hardware that can be controlled by your phone has grown. This technology allows you to lock and unlock your door from the other side of the globe, but for it to work there needs to be almost zero friction in the hardware. The force required to properly lock a multipoint hardware door is a big problem in this regard, and this is an issue that is yet to be fully resolved.
In the early days of NAFS and doors, it was discovered that wheelchair accessibility was becoming a problem. If doors were required to be water-tight (180 Pa or higher) and at the same time could only have a sill height of 1/2 an inch, how could this work? The physics says it can’t unless you apply an incredibly tight seal, which could be considered a “face sealed” system. The BC Building Code was subsequently amended to allow for Limited Water (LW) ratings on all doors that need to be wheelchair accessible regardless of their exposure.
The Energy Step Code and the requirement for greater airtightness in buildings also pose a problem. Whole building blower door testing is now necessary, and we are seeing much higher expectations on the air leakage of components such as doors. This isn’t an issue with triple weather-stripped and multipoint locking doors, but wheelchair-accessible sills result in less weather stripping and impact air tightness as well as water tightness. If a traditional door sill achieves an NAFS A3 rating, you can expect an A2 rating on a wheelchair assessable sill as it has less weatherstripping due to its shape.
So, what do we make of all of this? As new regulations come into force in one area, they can inadvertently affect others. There is a constant give and take in priorities, so the important question for your project becomes… what are your priorities? We are here to help balance them out and to find solutions that work, so let’s plan and engage early in the design process so we can address as many conflicts as possible.
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