A Heat-Transfer Rate Inducing System (H-TRIS) Test Method

Abstract

a b s t r a c t A novel fire testing method, named the Heat-Transfer Rate Inducing System (H-TRIS), is presented and described in this paper. The method directly controls the thermal boundary conditions imposed on a test specimen by controlling a specified time-history of incident radiant heat flux at its exposed surface. Accounting for the absorptivity and thermal losses at the exposed surface of the test specimen, H-TRIS can be programmed to control the net heat flux at the exposed surface; thus controlling the in-depth time dependent temperature distributions within the test specimen. H-TRIS can be used for imposing a wide range of time-histories of incident radiant heat flux (e.g. constant, linear, stepped), or in-depth time dependent temperature distributions (i.e. specified thermal gradients). Notably, this enables simulation of thermal boundary conditions experienced by materials or structures exposed to any source of heatduring a conventional fire test (e.g. standard furnace test), a large-scale fire test, a real fire, or some other thermal boundary conditions calculated using a fire model (e.g. zone or computational fluid dynamics model). H-TRIS enables complementary experimental studies with excellent repeatability at comparatively low economic and temporal costs relative to traditional furnace test methods, thus permitting multiple repeat tests and statistical studies of response to heating. Application of H-TRIS within a research project studying heat-induced concrete spalling is briefly presented and discussed, to illustrate the significance and novelty of the new fire testing method.

Auto-extinction of engineered timber: Application to compartment fires with exposed timber surfaces

“…Two TSCs were used for the timber calibrations to account for possible variability, and to allow the impact of different heating and cooling rates to be determined. All TSCs were calibrated using H-TRIS [171] to enable a time-varying heat flux to be imposed. Combining the relevant equations from [169], the calibration factor for a given TSC can be calculated from Equation 4.8:…”

Fire performance of closed‐cell charring insulation materials in plasterboard‐insulation assemblies

“…The test samples consisting of the plasterboard leaf and the insulation board were exposed to a radiative heat source. The system used was H-TRIS (Heat-Transfer Rate Inducing System), 26 which allows moving the radiant panels onto different positions in order to represent a different level of irradiation on the surface of the sample being tested. The calibration process to define the relation between heat flux and panels-sample distance is done with a watercooled Schmidt-Boelter gauge, as shown in Figure 3B.…”

The discrepancies in energy balance in furnace testing, a bug or a feature?

“…Another way to cope with substantial costs of furnace testing is scaled down experiments on small furnaces or with radiative panels. 27 However, in the opinion of authors, these methods cannot be yet considered as equivalent to fire testing, but rather as a supplementary method to quickly assess a variety of material solutions before a final large-scale test. The reason for this is that the heat exposure is just one of the aspects of a furnace test -loads (also the weight of the sample), fixing method, possible deformations, pressure difference between furnace and outside, etc also play a significant role in the test and are often not represented in reduced scale approach.…”

“…To cope with this, different time‐equivalence methods were proposed, but most of these methods have limited applicability or may lead to incorrect findings. Another way to cope with substantial costs of furnace testing is scaled down experiments on small furnaces or with radiative panels . However, in the opinion of authors, these methods cannot be yet considered as equivalent to fire testing, but rather as a supplementary method to quickly assess a variety of material solutions before a final large‐scale test.…”