The Wood Innovation and Design Centre (WIDC) in downtown Prince George, B.C., is constructed using a repeatable and expandable system to use on other building types and sizes. B.C. was the first province to allow for 12-storey mass timber construction. Image provided by Province of British Columbia.
Alberta has added variances to the Alberta Building Code to allow encapsulated mass timber construction (EMTC) of buildings up to 12-storeys.
These changes will also be in the 2020 National Building Code of Canada (NBCC) and the National Fire Code of Canada (NFCC) when they are published in early 2021.
“A variance provides an alternative solution of approximately equivalent or greater safety performance to the prescriptive requirements of the codes. Any construction that complies with this variance is permitted just as if the building was constructed under code requirements,” the Alberta government said in a Standata released on Feb. 19.
EMTC refers to buildings where the mass timber components of the building are surrounded or “encapsulated” with fire-resistive material. Code provisions were developed by the National Research Council and the Canadian Commission on Building and Fire Codes. The codes will provide an alternative solution to the National Building Code–2019 Alberta Edition (NBC(AE)) and the National Fire Code-2019 Alberta Edition (NFC(AE)).
The upcoming code provisions will also include additional requirements for fire protection during construction and ongoing maintenance.
Alberta has announced it will automatically enforce the national codes with minimal provincial variations 12-months from the publication date. “In order to advance the use of EMTC in Alberta, this variance will permit EMTC up to 12-storeys in building height anywhere in Alberta provided the conditions in this variance are complied with,” said the Standata.
The current requirements in the NBC(AE) separate buildings into two construction-type categories – combustible construction and non-combustible construction. The provisions restrict the height and area of buildings of combustible construction whereas they permit unlimited height and area for buildings of non-combustible construction.
“The combustible/non-combustible construction classification system was introduced in the National Codes over 50 years ago and is increasingly being regarded as being outdated and unnecessarily restrictive,” the Standata noted.
The NBC(AE) requires that buildings greater than six storeys in height be of non-combustible construction. This variance permits the construction of EMTC buildings of certain occupancy classifications up to 12 storeys in height.
