Description of small and large-scale cross laminated timber fire tests

Abstract

A large-scale fire test was conducted on a compartment constructed from cross laminated timber (CLT). The internal faces of the compartment were lined with non-combustible board, with the exception of one wall and the ceiling where the CLT was exposed directly to the fire inside the compartment. Extinction of the fire occurred without intervention. During the fire test, measurements were made of incident radiant heat flux, gas phase temperature, and in-depth temperature in the CLT. In addition, gas flow velocities and gas phase temperatures at the opening were measured, as well as incident heat fluxes at the facade due to flames and the plume leaving the opening. The fuel load was chosen to be sufficient to attain flashover, to achieve steadystate burning conditions of the exposed CLT, but to minimize the probability of uncertain behaviors induced by the specific characteristics of the CLT. Ventilation conditions were chosen to approximate maximum temperatures within a compartment. Wood cribs were used as fuel and, following decay of the cribs, selfextinction of the exposed CLT rapidly occurred. In parallel with the large-scale test, a small scale study focusing on CLT self-extinction was conducted. This study was used: to establish the range of incident heat fluxes for which self-extinction of the CLT can occur; the duration of exposure after which steady-state burning occurred; and the duration of exposure at which debonding of the CLT could occur. The large-scale test is described, and the results from both the small and large-scale tests are compared. It is found that selfextinction occurred in the large-scale compartment within the range of critical heat fluxes obtained from the small scale tests.

Exploring the fire behaviour of thin intumescent coatings used on timber

“…The samples kept burning for the whole duration of the test: no flame extinction was recorded for any of the uncoated samples during the fire test (see Figure 5). Indeed, the applied incident radiant heat flux was higher than the critical heat flux for selfextinguishment of typical CLT products, around 45 kW/m 2 [23]. As regards coated test samples (S06, S16, S25), ignition was only observed for two of three samples protected with a 0.6 mm WFT of intumescent coating (S06-A and S06-C).…”

“…Test samples were fire tested to a constant incident radiant heat flux of 50 kW/m 2 . The heating condition was selected to yield an onerous thermal condition at exposed surface of test samples and one for which it could be assured that no extinction (for uncoated samples) would occur during testing [23]. All test samples were tested for 60 minutes.…”

Thermal property and flame retardancy comparisons based on particle size and size distribution of clays in ethylene vinyl acetate (EVA) adhesive sheets for cross-laminated timber (CLT)

“…The most widely used interior material for wooden constructions is CLT, which consists of a lumber board, veneer, alternating particle and strand. In previous full-scale fire tests, CLT panels have been shown to have excellent fire resistance comparable to those of typical heavy construction assemblies of reinforced concrete buildings, due to the wood itself and the insulation effect from the formation of the char layer (Gagnon et al 2013;Emberley et al 2017). However, the main cause of adverse health effects due to fire is the bronchial damage and suffocation caused by the toxic gas rather than the damage caused by the fire.…”

Fire analysis of load-bearing bamboo structures

“…For materials that burn during fire (e.g. bamboo, timber), it is essential to ensure that the material will not continue to burn after burnout to demonstrate structural integrity (Emberley et al, 2017). If burnout in a bamboo structure is achieved, the structure survives and still provides appropriate structural performance during and after fire (Emberley et al, 2017).…”

“…bamboo, timber), it is essential to ensure that the material will not continue to burn after burnout to demonstrate structural integrity (Emberley et al, 2017). If burnout in a bamboo structure is achieved, the structure survives and still provides appropriate structural performance during and after fire (Emberley et al, 2017). Many factors can affect the conditions at which bamboo can sustain combustion after the burnout; critical heating conditions for self-extinguishment of bamboo and the potential for delamination of laminated bamboo are two key aspects that must be understood.…”