When the province introduced new building regulations in February, it also required applicable buildings to meet the National Energy Code for Buildings (2011 edition). Our office has seen a few issues with builders and designers not being aware of NECB or its impacts, so here’s a quick primer on what the NECB means.
First off, what is the NECB? Simply put, it’s an extremely detailed (and complex) set of codes aimed at reducing energy consumption in buildings, and its aimed largely at commercial buildings. The average homebuilder and homeowner can stop reading here, because simple single-family dwellings don’t have to follow the NECB: the general requirements for heat, light, insulation and the like are all covered in Part 9 of the National Building Code.
It’s also worth noting that the NECB doesn’t apply to all commercial buildings, either. Smaller shops and offices – specifically those less than 300m2 in area – can also make do with the basic requirements that apply to houses (for the most part.) In many of the larger buildings where the NECB does apply, a professional designer will handle all the requirements.
But that leaves a number of renovations, new builds, or changes of occupancy where a designer need not be involved, but NECB requirements apply. Here are some of the things a builder or owner should know:
Window limits:
Generally speaking, for buildings in our area, NEB places a limit of 34% of a building wall that can be glass or doors. The logic here is that windows – even the modern triple-glazed, argon-filled windows – are remarkably inefficient compared to a standard wall assembly. We love windows, but your energy bill doesn’t. It’s also worth noting that limits on window area also serve the needs of earthquake bracing, which will become mandatory when the 2015 Building Code comes into force in 2022.
Exterior walls:
The reason that 2x6 stud walls are common is that an R20 batt installed into a 2x6 wall cavity will meet the requirements for R17 effective insulation for residential walls. But that wall assembly doesn’t meet the standards for NECB, which requires R23 effective for exterior walls. This means that for new builds and renovations where NECB applies, our office needs to see a wall assembly that meets that R23 requirement. Examples of this include, most simply, a 2x6 wall with R22 batt insulation, sheathing, and a layer of 1.5” XPS foam insulation.
Automatic lights:
If you’ve been the first one into a changeroom in a modern hockey rink, you’ve opened the door to a dark room that immediately lights up.
Most open spaces in larger buildings will require either motion-sensing lights or lights controlled by a timer. There are some exemptions (such as areas where lights must be on full-time). It's also worth noting these motion-sensing lights will also be required in bathrooms, classrooms, meeting rooms, bathrooms, lunch rooms, small storage rooms, small office spaces and – as noted above - changerooms. The lights are designed to automatically cut power to the lights after 30 minutes of inactivity in the room, thus saving power.
Obviously, there is a lot more to the NECB than these quick highlights – limits to lighting power, requirements for efficiency in building components and the like. The full NECB can be found on the National Resource Council’s website.