Fire Code May Allow for Six Storey Wood Construction

A task group established in 2011 and encompassing several Canadian Commission on Building and Fire Codes (CCBFC) standing committees has found that subject to a number of conditions, buildings made of wood and other combustible materials could safely be built as high as six storeys.

The task group examined areas such as fire protection (building elements), emergency response (fire code requirements), building and plumbing services and structural and earthquake design.

According to a recent update from the National Research Council , the conditions under which wood buildings could be built to six storeys:

• a minimum of 25 per cent of the building perimeter must be directly accessible to fire responders
• mandatory sprinklers (conforming to NFPA-13) must be in place throughout the building
• a fire resistance rating of not less than one hour for floor and roof assemblies as well as mezzanines
• non-combustible cladding on roofs that are accessible to fire hoses
• buildings being occupied only after fire safety features are fully enabled

The proposed changes would apply to residential and office buildings (Group C and D occupancies in the building codes) along with mixed-type occupancies where Group C and D buildings, depending on the top occupancy, may have office, residential, mercantile, assembly, low hazard or storage garage-type occupancies (Group D, C, E, A2, F2 and F3, respectively) on the lower levels.

Following acceptance of the proposed changes by the CCBFC, the joint task group plans to review the codes in their entirety to see if the whole concept of combustible/non-combustible construction can be eliminated altogether or replaced with performance based requirements. Research is currently underway at the NRC Institute for Research in Construction with regard to fire safety and acoustic and building envelope performance to determine whether or not this is possible.

Proposed changes are also being developed with regard to structural and earthquake design, including changes to seismic force rating systems.

The policy implications of the proposed changes with regard to wood structure height requirements are expected to be discussed with provinces and territories during the coming summer and submitted for public review in fall.

Any final changes which are approved by the CCBFC and incorporated in the 2015 editions of the National Building and Fire Codes of Canada.

Top Image courtesy of Sukh Johal c/o WoodWORKS!BC

By Andrew Heaton