The purpose of this guide is to provide an introduction to the concept of encapsulated mass timber construction. This guide provides an overview of encapsulation techniques for mass timber construction, and other related fire protection measures, and summarizes some approved encapsulation materials and application methods and identifies additional requirements for safety during construction. This guide is intended to help architects, engineers and designers by reducing uncertainty and allowing for more confidence in design, as well as providing authorities having jurisdiction and inspectors with a reference for simple design review.
The superior fire performance of timbers can be attributed to the charring effect of wood. As wood members are exposed to fire and the wood begins to burn, a char layer is formed. The char layer acts as an insulator and protects the core of the wood sect...
The Task Group on Combustible Construction is in the process of evaluating a proposed code change request related to buildings of encapsulated mass timber construction (EMTC). As part of the analysis of the code change request, an impact analysis is required that includes a cost-benefit analysis.
Hanscomb was hired to provide a cost-benefit analysis and to compare the estimated value of the following:
1. The cost of constructing a building of mass timber (unprotected) versus a building constructed of encapsulated mass timber (e.g. mass timber protected with a double layer of Type X gypsum board) versus a traditional concrete and steel building.
2. The time to build a building of mass timber construction (unprotected) versus a building of encapsulated mass timber construction versus a traditional concrete and steel building.
3. The annual maintenance costs of building of mass timber construction versus a building of encapsulated mass timber construction versus a traditional concrete and steel building.
For the purposes of this study two sets of conceptual floor plans and elevations have been created:
1. A 12 storey building with a Group C major occupancy (residential) where each storey is 6,000 m2 in floor area.
2. A 12 storey building with a Group D major occupancy (office) where each storey is 7,200 m2 in floor area.
The objective of the two tests described in this report was to evaluate the performance of cross-laminated timber (CLT) and nail laminated timber (NLT) construction protected with two layers of %-in. (16-mm) type X gypsum board when exposed to the therma...
These Joint Professional Practice Guidelines – Encapsulated Mass Timber Construction Up to 12 Storeys were jointly prepared by the Architectural Institute of British Columbia (AIBC) and Engineers and Geoscientists British Columbia.
The AIBC and Engineers and Geoscientists BC regulate and govern the professions of architecture, engineering, and geoscience under the Architects Act and the Professional Governance Act. The AIBC and Engineers and Geoscientists BC each have a regulatory mandate to protect the public interest, which is met in part by setting and maintaining appropriate academic, experience, and professional practice standards.
Engineering Professionals are required per Section 7.3.1 of the Bylaws - Professional Governance Act to have regard for applicable standards, policies, plans, and practices established by the government or by Engineers and Geoscientists BC, including professional practice guidelines. For Engineering Professionals, these professional practice guidelines clarify the expectations for professional practice, conduct, and competence when providing engineering services for EMTC buildings.
For Architects, these guidelines provide important information and identify issues to be considered when providing architectural services for EMTC buildings.
These guidelines deal with the performance of specific activities in a manner such that Architects and Engineering Professionals can meet their professional obligations under the Architects Act and the Professional Governance Act.
These guidelines were developed in response to new classifications of building size and construction relative to occupancy introduced in the 2018 British Columbia Building Code (BCBC), under Division B, Article 18.104.22.168EMTC. Group C, up to 12 storeys, Sprinklered, and Article 22.214.171.124EMTC. Group D, up to 12 storeys, Sprinklered. These new classifications were introduced in Revision 2 of the 2018 BCBC on December 12, 2019 and in Amendment 12715 of the 2019 Vancouver Building By-law (VBBL) on July 1, 2020. Additionally, provisions related to Encapsulated Mass Timber Construction (EMTC) were introduced in Revision 1 of the 2018 British Columbia Fire Code (BCFC) on December 12, 2019.
These guidelines were first published in 2021 to provide guidance on architectural and engineering considerations relating to these significant changes to the 2018 BCBC, the 2019 VBBL, and the 2018 BCFC.
For Engineering Professionals, these guidelines are intended to clarify the expectations of professional practice, conduct, and competence when Engineering Professionals are engaged on an EMTC building.
For Architects, these guidelines inform and support relevant competency standards of practice to be met when Architects are engaged on an EMTC building.
As with all building and construction types, the EMTC-specific code provisions prescribe minimum requirements that must be met.
The majority of EMTC of 7 to 12 storeys are considered High Buildings, and as such are subject to the BCBC, Subsection 3.2.6. Additional Requirements for High Buildings.
This paper discusses the principles of performance based structural design and motivates the need for probabilistic assessment of the response of structures and an assessment of the consequences of failure. Using the results from a series of tests carried out at SP in Sweden, we extrapolate data required for the assessment of timber...
This paper presents a numerical model for heat transfer in timber structures. The thermal behaviour is described by the standard Fourier heat equation. The chosen model integrates the three modes of heat transfer; namely: conduction, radiation and convection during the fire exposure...
This paper summarizes the experimental results from a series of tests that investigated the performance of timber-to-steel tensile connections exposed to fire. A series of fire-resistance tests were conducted on bolted wood-steelwood and steel-wood-steel connections loaded in tension. Each specimen had different cross-sectional area, fastener...