FPInnovations carried out a survey with consultants and researchers on the use of analytical models and software packages related to the analysis and design of mass timber buildings. The responses confirmed that a lack of suitable models and related information for material properties of timber connections was creating an impediment to the design and construction of this type of buildings. Furthermore, there is currently a lack of computer models and expertise for carrying out performance-based design for wood buildings, in particular seismic and/or fire performance design.
In this study, a sophisticated constitutive model for wood-based composite material under stress and temperature was developed. This constitutive model was programmed into a user-subroutine which can be added to most general-purpose finite element software. The developed model was validated with test results of a laminated veneer lumber (LVL) beam and glulam bolted connection under force and/or fire.
In an objective to evaluate the surface burning characteristics of massive timber assemblies such as CLT and SCL, flame spread tests on massive timber assemblies have been conducted in accordance with ULC S102 test method. This study evaluated the flame spread of fully exposed massive timber specimens (i.e. untreated/uncoated) as well as the effect on flame spread by using intumescent coating with CLT. Test results provide low flame spread ratings when compared to those of common combustible interior finish materials provided in Appendix D-3 of NBCC. Specifically, the obtained flame spread ratings of 3-ply CLT assemblies of 105 mm in thickness are 35 and 25 for a fully exposed CLT (untreated) and for a CLT panel protected by intumescent coating respectively. Fully exposed SCL of 89 mm in thickness provided ratings of 35 and 75 for parallel strand lumber (PSL) and laminated strand lumber (LSL) respectively.
A series of 3 cross-laminated timber (CLT) fire-resistance tests were conducted in accordance with ULC S101 standard as required in the National Building Code of Canada.
The first two tests were 3-ply wall assemblies which were 105 mm thick, one unprotected and the other protected with an intumescent coating, FLAMEBLOC® GS 200, on the exposed surface. The walls were loaded to 295 kN/m (20 250 lb./ft.). The unprotected assembly failed structurally after 32 minutes, and the protected assembly failed after 25 minutes.
The third test consisted of a 175 mm thick 5-ply CLT floor assembly which used wood I-joists, resilient channels, insulation and 15.9 mm ( in.) Type X gypsum board protection. A uniform load of 5.07 kPa (106 lb./ft²) was applied. The floor assembly failed after 138 min due to integrity.
Nowadays, the fire behavior of CLT panels made from solid-sawn lumber exposed to fire is well known and documented by a number of research organizations and universities. However, due to the desire to optimize how material is used in CLT, and ultimately lower manufacturing costs, CLT with thin laminations ranging from 19 to 25 mm in thickness has started to be produced in North America, which somewhat limits the applicability of some design provisions which were derived and validated from CLT made with 35-mm laminations. There is currently limited research on CLT manufactured with thin laminations, namely with respect to their fire behavior and specifically the effective charring rate.
In order to address the lack of consistency in the charring models of CLT with thin laminations, FPInnovations conducted a series of fire tests to further evaluate and document the impact on the charring rate from using thin laminations. The objective of this study is to evaluate the charring behavior of CLT manufactured in accordance with ANSI/APA PRG-320 with thin laminations of various thicknesses (less than 35 mm).
The main objective of this preliminary study is to evaluate the heat release rate and fire growth contribution due to heat delamination characteristics of CLT manufactured with current certified ANSI/APA PRG-320 adhesives used for face bonding, when exposed to a constant radiant heat flux. The evaluation is performed using the principles of ISO 5660-1 “Reaction-to-fire tests - Heat release, smoke production and mass loss rate – Part 1: Heat release rate (cone calorimeter method)” . The American version of this test method is ASTM E1354 « Standard Test Method for Heat and Visible Smoke Release Rates for Materials and Products Using an Oxygen Consumption Calorimeter » .
The long-term objective is to determine which currently accepted test methods allow for a better evaluation of heat delamination characteristics of adhesives used in structural engineered wood products, based on their actual end-use applications (e.g. bending, compression, combined stress, cross-plies, etc.)
The following report provides background information on the standard test method used in Canada to evaluate fire stop systems, ULC S115, “Standard Method of Fire Tests of Firestop Systems” and the regulatory requirements specified in the National Building Code of Canada (NBCC).
A review of research conducted in Europe demonstrates that fire stop systems currently used in reinforced concrete and light-frame construction can be used with success in solid wood construction. While testing conducted in Europe has largely relied on lining the reveal of openings with gypsum board, a limited number of tests indicate that lining methodology using gypsum board may not be necessary in all cases.
The highest priority for facilitating the development and approval of fire stop systems is in wood structures up to 6 storeys tall. This is due to the fact that these buildings are currently permitted in the British Columbia Building Code (BCBC) and are likely to be permitted in other provinces as well as in the 2015 edition of the NBCC.
In order to help the wood industry in moving forward in addressing fire stops issues, three paths are identified and discussed in which the wood industry could facilitate the development of approved fire stop systems for solid wood construction. Ultimately, it is the fire stop manufacturers who must conduct testing in order to seek fire stop listings. Therefore, it is highly recommended that testing be conducted in cooperation with one or more fire stop manufacturers.
An advanced modelling tool, WoodST, has been developed for fire safety analysis of timber structures. It is demonstrated that this advanced modelling tool can predict the structural response of LVL beams, glulam bolted connections, OSB-web I-joist and wood-frame floors under forces and fire conditions with an accuracy acceptable to design practitioners (i.e., within 10% of test data). The developed modelling tool can:
Fill the gap in terms of suitable models for timber connections, which is an impediment for the design and construction of tall wood buildings;
Provide a cost-effective simulation solution compared to costly experimental solutions; and
Significantly reduce the cost and shorten the time for the development and/or optimization of new wood-based products and connections.
The objective of this project is to establish fundamental fire performance data for the design and specification of NLT assemblies; this project specially addresses determining FSRs for NLT. The goal of this project is to confirm that NLT, when used as a mass timber element, has a lower FSR than standard thickness SPF boards when tested individually and flatwise. The project also considers how the surface profiles, design details, and the direction of an assembly might influence flame spread. This includes the evaluation of typical architectural features, such as a 'fluted' profile.
Fire safety regulations impose very strict requirements on building design, especially for buildings built with combustible materials. It is believed that it is possible to improve the management of these regulations with a better integration of fire protection aspects in the building information modeling (BIM) approach. A new BIM-based domain is emerging, the automated code checking, with its growing number of dedicated approaches. However, only very few of these works have been dedicated to managing the compliance to fire safety regulations in timber buildings. In this paper, the applicability to fire safety in the Canadian context is studied by constituting and executing a complete method from the regulations text through code-checking construction to result analysis. A design science approach is used to propose a code-checking method with a detailed analysis of the National Building Code of Canada (NBCC) in order to obtain the required information. The method starts by retrieving information from the regulation text, leading to a compliance check of an architectural building model. Then, the method is tested on a set of fire safety regulations and validated on a building model from a real project. The selected fire safety rules set a solid basis for further development of checking rules for the field of fire safety. This study shows that the main challenges for rule checking are the modeling standards and the elements’ required levels of detail. The implementation of the method was successful for geometrical as well as non-geometrical requirements, although further work is needed for more advanced geometrical studies, such as sprinkler or fire dampers positioning.