Frequently Asked Questions - Technical
Fire Safety in a Completed Encapsulated Mass Timber Construction (EMTC) Building
- Buildings must be sprinklered throughout
- EMTC buildings are generally limited to residential and office (“business and personal services”) occupancies. (Some assembly and retail occupancies are permitted below the fourth and third storeys respectively, and storage garages are permitted below the fifth storey)
- Except for limited areas and locations, mass timber elements and assemblies must be encapsulated with fire resistive materials
- “High” buildings of encapsulated mass timber construction (buildings that are 7 to 12 storeys in height) have the same additional requirements as “high” buildings of non-combustible construction
Though the primary structural materials are different, 7 to 12-storey EMTC and non-combustible buildings share the same principal fire safety features
- Two-hour structural fire resistance
- ‘High’ building provisions
- Fire sprinklers throughout the building
A fire resistance rating (FRR) represents the time that an assembly of materials will withstand the passage of flame or transmission of heat. A material assembly includes the main material (e.g., mass timber) and the encapsulation material if present.
An encapsulation rating represents the time that a material will delay ignition and combustion of an encapsulated mass timber element.
Type X gypsum board, gypsum concrete topping or any non-combustible material with an encapsulation rating of no less than 50 minutes can be used for encapsulation.
As for all buildings, a fire safety plan will be required for all buildings. The process for enabling tall wood construction will require local authorities ensure that there is an enforced holistic strategy to address exposed mass timber during the course of construction in the fire safety plan. Additional protective measures can be included in the fire plan.
Fire Safety in an EMTC building Under Construction
New requirements related to EMTC buildings are noted in the revised 2018 BC Fire Code. These include:
- Availability of Adequate Water Supply for Firefighting as soon as combustible or encapsulated mass timber construction material arrives at the construction site
- There are also Standpipe provisions, set testing, installation, warning systems and other requirements for fire department connections for each new level with hose valve
- Secondary stairwell and stairwell requirements for worker egress - 30-minute fire protection rating
- Specific doors assemblies to increase fire protection: 45 mm solid core wood doors, hollow metal doors, door of minimum 12.7 mm thick gypsum board - 20 minutes fire protection rating
Limitations on Exposed Wood:
- Additional requirements for encapsulation materials which delay the time it takes for fire to reach mass timber by 50 minutes (encapsulation rating)
- Not more than 20% of the underside area of each mass timber floor may be exposed during construction
- Not more than 35% of total area of structural mass timber walls within each storey may be exposed during construction
- Not more than four of the uppermost adjoining storeys may be unprotected during construction
- Additional guidance for the “Protection of Adjacent Buildings” with respect to the development of a fire safety plan
The content on this page was updated by the Province of British Columbia on June 25, 2020.