Cross-laminated timber is a relatively new engineered timber material that can be used in the design and construction of modern timber buildings. A key factor that raises concerns in the wide application of cross-laminated timber is the uncertainty of its fire performance. This article describes experimental and numerical investigations on the fire behaviour of loaded cross-laminated timber panels manufactured with Canadian hemlock. A total of 10 cross-laminated timber panels with different number and thickness of layers were tested under ambient and standard fire conditions to investigate the flexural capacity at ambient temperature, and temperature distribution, charring rate, fire resistance, mid-span deflection under fire exposure. Three-dimensional finite element model was developed using the Hashin criterion and cohesive elements to predict the failure of wood and adhesive, respectively. The thermal model implicitly considers the rapidly increased temperature of inner fresh timber after the protective charred layers have fallen off. The numerical model was validated with the results obtained from experimental tests and was found to have the ability to simulate the fire behaviour of loaded cross-laminated timber panels in reasonable accuracy.
The objective of this study is to evaluate the fire behavior of CLT manufactured with different types of SCL or lumber boards, namely with laminated veneer lumber (LVL), laminated strand lumber (LSL) and Trembling Aspen. The fire test data is also compared to those of CLT manufactured in accordance with ANSI/APA PRG-320 using solid-sawn lumber grades. More specifically, the study aims at evaluating the charring rates of this new generation of CLT panels as well as the impact of their manufacturing parameters.
This thesis studies the fire behaviour of Cross Laminated Timber (CLT) panels in partially protected rooms. A one-dimensional heat transfer model was developed to determine the fire resistance of CLT floor and wall panels. During this study, three room fire tests were conducted at Carleton University Fire Research Laboratory to determine the maximum percentage of unprotected CLT surface area that will yield similar results to that of a fully protected room. The rooms had a single opening and were constructed entirely using 3-ply, 105 mm thick CLT panels. A non-standard, parametric fire using furniture and clothing as fuel was used and 2 layers of gypsum board were used to cover the ceiling and the protected walls. The Heat Release Rate, temperature, charring rate and gypsum falloff time of each test was collected. The results obtained from the room test were then compared to the numerical heat transfer model to evaluate its accuracy.
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).
In this research the effect of using the combustible material CLT as the main bearing structure is investigated. As a combustible material, unprotected CLT can burn along with the fuel load present in a compartment.
This master’s thesis aims to increase insight into the fire behaviour of unprotected CLT structures in a compartment burnout, conservatively assuming no active measures. The main research question of this work is: “Under what conditions is there a potential for self-extinguishment of cross-laminated timber?” A model of self-extinguishment of CLT was created which consists of various phases of a compartment burnout. Under the influence of an initial fire due to burning of room contents, the exposed CLT becomes involved in flaming combustion. Once the room contents have been largely consumed and the initial fire decays, the CLT contribution is expected to decrease as well, transforming from flaming to smouldering combustion. Finally, there will be a transition from smouldering to self-extinguishment. Two series of experiments were conducted to investigate this model and the conditions under which the transitions can take place.