BUILDING CODES – CWC participates extensively in the development process of the Building Codes in Canada. CWC is a member of both National and Provincial Building Code Committees. These Committees are balanced and representation is limited to about 25 members on each Committee. Competing interests (i.e. steel and concrete) sit on the same Committees. This is an arena where CWC can win or lose ground for members’ products.

National Fire Code of Canada

The National Building Code of Canada (NBC) and the National Fire Code of Canada (NFC), both published by the National Research Council of Canada (NRC) and developed by the Canadian Commission on Building and Fire Codes (CCBFC), are developed as companion documents.

The NBC establishes minimum standards for the health and safety of the occupants of new buildings. It also applies to the alteration of existing buildings, including changes in occupancy. The NBC is not retroactive. That is, a building constructed in conformance with a particular edition of the NBC, which is in effect at the time of its construction, is not automatically required to conform to the subsequent edition of the NBC. That building would only be required to conform to an updated version of the NBC if it were to undergo a change in occupancy or alterations which invoke the application of the new NBC in effect at the time of the change in occupancy or major alteration.

The NFC addresses fire safety during the operation of facilities and buildings. The requirements in the NFC, on the other hand, are intended to ensure the level of safety initially provided by the NBC is maintained. With this objective, the NFC regulates:

• the conduct of activities causing fire hazards
• the maintenance of fire safety equipment and egress facilities
• limitations on building content, including the storage and handling of hazardous products
• the establishment of fire safety plans

The NFC is intended to be retroactive with respect to fire alarm, standpipe and sprinkler systems. In 1990, the NFC was revised to clarify that such systems “shall be provided in all buildings where required by and in conformance with the requirements of the National Building Code of Canada.” This ensures that buildings are adequately protected against the inherent risk at the same level as the NBC would require for a new building. It does not concern other fire protection features such as smoke control measures or firefighter’s elevators. The NFC also ensures that changes in building use do not increase the risk beyond the limits of the original fire protection systems.

The NBC and the NFC are written to minimize the possibility of conflict in their respective contents. Both must be considered when constructing, renovating or maintaining buildings. They are complementary, in that the NFC takes over from the NBC once the building is in operation. In addition, older structures which do not conform to the most current level of fire safety can be made safer through the requirements of the NFC.

The most recent significant changes in the NFC relate the construction of six-storey buildings using combustible construction. As a result, eight additional protection measures related to mid-rise combustible buildings have been added to address fire hazards during construction when fire protection features are not yet in place.

For further information, refer to the following resources:

Fire Safety Design in Buildings (Canadian Wood Council)

Codes Canada – National Research Council of Canada

National Building Code of Canada

National Fire Code of Canada

Fire Safety and Security: A Technical Note on Fire Safety and Security on Construction Sites in Ontario/British Columbia (Canadian Wood Council)

The National Energy Code of Canada for Buildings (NECB) aims to help save on energy bills, reduce peak energy demand, and improve the quality and comfort of the building’s indoor environment. Through each code development cycle, the NECB intends to implement a tiered approach toward Canada’s goal for new buildings, as presented in the “Pan-Canadian Framework on Clean Growth and Climate Change”, of achieving ‘Net Zero Energy Ready’ buildings by 2030.

The NECB is available for free online; published by the National Research Council (NRC) and developed by the Canadian Commission on Building and Fire Codes in collaboration with Natural Resources Canada (NRCan). CWC maintains ongoing participation in the development and updating of the NECB.

The NECB sets out technical requirements for energy efficient design and construction and outlines the minimum energy efficiency levels for code compliance of all new buildings. The NECB applies to all building types, except housing and small buildings, which are addressed under Clause 9.36 of the National Building Code of Canada. The NECB offers three compliance paths: prescriptive, trade-off and performance.

The most cost-effective time to incorporate energy efficiency measures into a building is during the initial design and construction phase. It is much more expensive to retrofit later. This is particularly true for the building envelope, which includes exterior walls, windows, doors and roofing. The NECB addresses considerations such as air infiltration rates (air leakage) and thermal transmission of heat through the building envelope. Considering the different climate zones in Canada, the NECB also provides requirements related to maximum overall (effective) thermal transmittance for above-ground opaque wall assemblies and effective thermal resistance of assemblies in contact with ground, e.g., permanent wood foundations. In addition, the NECB specifies the maximum fenestration and door to wall ratio based on the climate zone in which the building in located.

As energy efficiency requirements for buildings are increased, wood is a natural solution to pair with other insulating and weatherizing materials to develop buildings with high operational energy performance and provide consistent indoor comfort for occupants.

For further information on the NECB, visit the Codes Canada at the National Research Council Canada.

• CSA O86 Engineering design in wood
• CSA S-6 Canadian Highway Bridge Design Code
• CSA S406 Permanent Wood Foundations
• CSA 080 Wood Preservation

Wood is composed of many small cellular tubes that are predominantly filled with air. The natural composition of the material allows for wood to act as an effective acoustical insulator and provides it with the ability to dampen vibrations. These sound-dampening characteristics allow for wood construction elements to be specified where sound insulation or amplification is required, such as libraries and auditoriums. Another important acoustical property of wood is its ability to limit impact noise transmission, an issue commonly associated with harder, more dense materials and construction systems.

The use of topping or a built-up floating floor system overlaid on light wood frame or mass timber structural elements is a common approach to address acoustic separation between floors of a building. Depending on the type of materials in the built-up floor system, the topping can be applied directly to the wood structural members or over top of a moisture barrier or resilient layer. The use of gypsum board, absorptive (batt/loose-fill) insulation and resilient channels are also critical components of a wood-frame wall or floor assembly that also contribute to the acoustical performance of the overall assembly.

Acoustic design considers a number of factors, including building location and orientation, as well as the insulation or separation of noise-producing functions and building elements. Sound Transmission Class (STC), Apparent Sound Transmission Class (ASTC) and Impact Insulation Class (IIC) ratings are used to establish the level of acoustic performance of building products and systems. The different ratings can be determined on the basis of standardized laboratory testing or, in the case of ASTC ratings, calculated using methodologies described in the NBC.

Currently, the National Building Code of Canada (NBC) only regulates the acoustical design of interior wall and floor assemblies that separate dwelling units (e.g. apartments, houses, hotel rooms) from other units or other spaces in a building. The STC rating requirements for interior wall and floor assemblies are intended to limit the transmission of airborne noise between spaces. The NBC does not mandate any requirements for the control of impact noise transmission through floor assemblies. Footsteps and other impacts can cause severe annoyance in multifamily residences. Builders concerned about quality and reducing occupant complaints will ensure that floors are designed to minimize impact transmission.

Beyond conforming to the minimum requirements of the NBC in residential occupancies, designers can also establish acoustic ratings for design of non-residential projects and specify materials and systems to ensure the building performs at that level. In addition to limiting transmission of airborne noise through internal structural walls and floors, flanking transmission of sound through perimeter joints and sound transmission through non-structural partition walls should also be considered during the acoustical design.

Further information and requirements related to STC, ASTC and IIC ratings are provided in Appendix A of the NBC in sections A-9.10.3.1. and A-9.11.. This includes, inter alia, Tables 9.10.3.1-A and 9.10.3.1.-B that provide generic data on the STC ratings of different types of wood stud walls and STC and IIC ratings for different types of wood floor assemblies, respectively. Tables A-9.11.1.4.-A to A-9.11.1.4.-D present generic options for the design and construction of junctions between separating and flanking assemblies. Constructing according to these options is likely to meet or exceed an ASTC rating of 47 that is mandated by the NBC. Table A-Table 9.11.1.4. presents data about generic floor treatments that can be used to improve the flanking sound insulation performance of lightweight framed floors, i.e., additional layers of material over the subfloor (e.g. concrete topping, OSB or plywood) and finished flooring or coverings (e.g., carpet, engineered wood).

In addition to combustible, heavy timber and noncombustible construction, a new construction type is presently being considered for inclusion into the National Building Code of Canada (NBC). Encapsulated mass timber construction (EMTC) is proposed to be defined as the “type of construction in which a degree of fire safety is attained by the use of encapsulated mass timber elements with an encapsulation rating and minimum dimensions for the structural timber members and other building assemblies.” EMTC is neither ‘combustible construction’ nor ‘heavy timber construction’ nor ‘noncombustible construction’, as defined within the NBC.

EMTC is required to have an encapsulation rating. The encapsulation rating is the time, in minutes, that a material or assembly of materials will delay the ignition and combustion of encapsulated mass timber elements when it is exposed to fire under specified conditions of test and performance criteria, or as otherwise prescribed by the NBC. The encapsulation rating for EMTC is determined through the ULC S146 test method.

In order for structural wood elements to be considered ‘mass timber’, they must meet minimum size requirements, which are different for horizontal (walls, floors, roofs, beams) and vertical (columns, arches) load-bearing elements and dependent on the number of sides that the element is exposed to fire.

EMTC construction in Canada is expected to be limited to a height of twelve-storeys, that is, the uppermost floor level may be a maximum of 42 m (137 ft) above the first floor. An EMTC building must be sprinklered throughout according to NFPA 13 and it is likely that some mass timber will also be able to be exposed in the suites. All EMTC elements are expected to have a minimum two-hour fire resistance rating and the building floor area to be limited to 6,000 m² for Group C occupancy and 7,200 m² for Group D occupancy.

There are restrictions on the use of exterior cladding elements in EMTC, as well as other restrictions on the use of; combustible roofing materials, combustible window sashes and frames, combustible components in exterior walls, nailing elements, combustible flooring elements, combustible stairs, combustible interior finishes, combustible elements in partitions, and concealed spaces.

If any encapsulation material is damaged or removed, it will be required to be repaired or replaced so that the encapsulation rating of the materials is maintained.

Additionally, requirements related to construction site fire safety are to be applied to construction access, standpipe installation and protective encapsulation.

EMTC and its related provisions are anticipated to be included in the NBC 2020.

NBC definitions:

Combustible means that a material fails to meet the acceptance criteria of CAN/ULC-S114, “Test for Determination of Non-Combustibility in Building Materials.”

Combustible construction means that type of construction that does not meet the requirements for noncombustible construction.

Heavy timber construction means that type of combustible construction in which a degree of fire safety is attained by placing limitations on the sizes of wood structural members and on thickness and composition of wood floors and roofs and by the avoidance of concealed spaces under floors and roofs.

Noncombustible construction means that type of construction in which a degree of fire safety is attained by the use of noncombustible materials for structural members and other building assemblies.

Noncombustible means that a material meets the acceptance criteria of CAN/ULC-S114, “Test for Determination of Non-Combustibility in Building Materials.”

For further information, refer to the following resources:

ULC S146 Standard Method of Test for the Evaluation of Encapsulation Materials and Assemblies of Materials for the Protection of Mass Timber Structural Members and Assemblies

Fire performance of mass-timber encapsulation methods and the effect of encapsulation on char rate of cross-laminated timber (Hasburgh et al., 2016)

CAN/ULC-S114 Test for Determination of Non-Combustibility in Building Materials

NFPA 13 Standard for the Installation of Sprinkler Systems