scholarly journals Fire Behavior of Thermally Thin Materials in Cone Calorimeter

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1297
Author(s):  
Marouane El El Gazi ◽  
Rodolphe Sonnier ◽  
Stéphane Giraud ◽  
Marcos Batistella ◽  
Shantanu Basak ◽  
...  
Keyword(s):  
Heat Flux ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Cone Calorimeter ◽  
Fire Hazard ◽  
Heat Of Combustion ◽  
Sample Weight ◽  
Effective Heat ◽  
Effective Heat Of Combustion

In this study, a representative set of thermally thin materials including various lignocellulosic and synthetic fabrics, dense wood, and polypropylene sheets were tested using a cone calorimeter at different heat fluxes. Time-to-ignition, critical heat flux, and peak of heat release rate (pHRR) were the main parameters considered. It appears that the flammability is firstly monitored by the sample weight. Especially, while the burning rate of thermally-thin materials does never reach a steady state in cone calorimeter, their pHRR appears to be mainly driven by the fire load (i.e., the product of sample weight and effective heat of combustion) with no or negligible influence of textile structure. A simple phenomenological model was proposed to calculate the pHRR taking into account only three parameters, namely heat flux, sample weight, and effective heat of combustion. The model allows predicting easily the peak of heat release rate, which is often considered as the main single property informing about the fire hazard. It also allows drawing some conclusions about the flame retardant strategies to reduce the pHRR.

scholarly journals Fire Risk of Halogen-Free Electrical Cable

2018 ◽  
Vol 26 (42) ◽  
pp. 21-27
Author(s):  
Jozef Martinka ◽  
Peter Rantuch ◽  
Igor Wachter ◽  
Karol Balog
Keyword(s):  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Fire Risk ◽  
Heat Of Combustion ◽  
Total Heat Release ◽  
Electrical Cable ◽  
Effective Heat ◽  
Effective Heat Of Combustion ◽  
Halogen Free

Abstract This paper deals with the fire risk of a selected halogen-free electrical cable. The research was objected to a three-core power electric cable for a fixed installation CHKE J3x1.5 (cross section of each copper core was 1.5 mm2) with a declared class of reaction to fire B2ca, s1, d1, a1. The electrical cable was manufactured and supplied by VUKI, a. s., Slovakia. The fire risk of the electric cable was evaluated based on the heat release rate, total heat release, smoke release rate, total smoke release and effective heat of combustion. These parameters were measured using a cone calorimeter at 50 kW m−2 (specimens and cone emitter were placed horizontally during the test). The measured electrical cable showed a maximum heat release rate of nearly 150 kW m−2, a maximum average heat emission rate of almost 100 kW m−2, a total heat release of almost 130 MJ m−2, a maximum smoke release rate of almost 2.5 s−1, a total smoke release of more than 800 m2 m−2, an effective heat of combustion (cable as a whole) of nearly 9 MJ kg−1 and an effective heat of emission (polymeric parts of the cable) of 26.5 MJ kg−1.

Heat Release Rate and Effective Heat of Combustion Measurements: A Comparative Study of Thermal and Oxygen Consumption Techniques

1995 ◽  
Vol 13 (6) ◽  
pp. 482-499 ◽  
Author(s):  
Fatima Moussan ◽  
Jean-Louis Delfau ◽  
Christian Vovelle ◽  
Christian Pham Van Cang ◽  
Gérard Bosseboeuf
Keyword(s):  
Oxygen Consumption ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Radiant Heat ◽  
Heat Of Combustion ◽  
Second Step ◽  
Thermal Method ◽  
Effective Heat ◽  
Effective Heat Of Combustion

A new calorimeter especially built for the measurement of the heat release rate and effective heat of combustion of composite materials is pre sented. Two procedures can be used to obtain these data: the first one is based on the direct measurement of the convective and radiant heat liberated by the flame, the second involves oxygen consumption measurement. Preliminary ex periments were carried out with a gas burner to calibrate and check the inertia of the thermal method. In a second step, measurements were performed on PMMA and PVC samples. The results obtained with both methods are very similar and in agreement with literature values.

A Comparison of the Behaviour of Spruce Wood and Polyolefins during the Test on the Cone Calorimeter

2013 ◽  
Vol 726-731 ◽  
pp. 4280-4287 ◽  
Author(s):  
Jozef Martinka ◽  
Emília Hroncová ◽  
Tomáš Chrebet ◽  
Karol Balog
Keyword(s):  
Heat Flux ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Cone Calorimeter ◽  
Lower Sensitivity ◽  
Average Heat ◽  
Fire Propagation ◽  
Spruce Wood

This article deals with comparison of the behaviour of spruce wood and polyolefins (polyethylene PE and polypropylene PP) during the test on the cone calorimeter. Samples were tested on the cone calorimeter at heat flux of 20 and 40 kW/m2. An evaluation of the behaviour of examined materials was based on the determination of the maximum and the average heat release rate, yield of carbon monoxide (CO), and relative comparison of tendency to fire propagation in a flashover phase. The tendency of materials to fire propagation in the flashover phase was evaluated based on the Pearson ́s correlation, the Spearman ́s correlation and the Kendall ́s correlation coefficient of HRR-CO and CO2-CO. Spruce wood showed better properties in comparison with PE and PP in all evaluated parameters (the maximum and the average heat release rate, the yield of CO, and also the resistance to fire propagation in the flashover phase. Additionally, spruce wood showed significantly lower sensitivity of dependence of the maximum and also the average heat release rate on external heat flux.

scholarly journals INVESTIGATION THE FIRE HAZARD OF PLYWOODS USING A CONE CALORIMETER

Wood Research ◽  
2021 ◽  
Vol 66 (6) ◽  
pp. 933-942
Author(s):  
ZHIGANG WU ◽  
XUE DENG ◽  
LIFEN LI ◽  
LIPING YU ◽  
JIE CHEN ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Cone Calorimeter ◽  
High Efficiency ◽  
Fire Hazard ◽  
Mass Loss Rate ◽  
Fire Retardant ◽  
Safety Level

A high-efficiency fire retardant composition was prepared with dicyandiamide, phosphoric acid, boric acid, borax, urea and magnesium sulfate and it was used to process veneers which were then to prepare the plywood. Meanwhile, heat release and smoke release from combustion of plywood were tested by a cone calorimeter, including heat release rate, mass loss rate, CO yield, CO2 yield and oxygen consumption. Results showed that the plywood with this fire retardant treatment had the better flame-retardant performance and smoke suppression effect as well as the stronger char-forming capability compared to plywood without fire retardant treatment. The average heat release rate, total heat release, average effective heat of combustion, total smoke release, CO yield and oxygen consumption of the plywood with fire retardant treatment were decreased by 63.72%, 91.94%, 53.70%, 76.81%, 84.99% and 91.86%, respectively. Moreover, the fire growth index of plywood treated by fire retardant was relatively low (3.454 kW·m-2·s-1) and it took longer time to reach the peak heat release rate, accompanied with slow fire spreading. The fire performance index was relatively high (0.136 s·m2·kW-1) and it took longer time to be ignited, thus leaving a long time for escaping at fire accidents. The fire hazard of plywood with fire retardant treatment was low, and its safety level was high.

scholarly journals Inversion for Fire Heat-Release Rate Using Heat Flux Measurements

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Andrew J. Kurzawski ◽  
Ofodike A. Ezekoye
Keyword(s):  
Heat Flux ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Fire Hazard ◽  
Computational Cost ◽  
Inversion Algorithm ◽  
Fire Dynamics ◽  
Oxygen Consumption Calorimetry ◽  
Flux Measurements

Abstract In fire hazard calculations, knowledge of the heat-release rate (HRR) of a burning item is imperative. Typically, room-scale calorimetry is conducted to determine the HRRs of common combustible items. However, this process can be prohibitively expensive. In this work, a method is proposed to invert for the HRR of a single item burning in a room using transient heat flux measurements at the walls and ceiling near the item. The primary device used to measure heat flux is the directional flame thermometer (DFT). The utility of the inverse method is explored on both synthetically generated and experimental data using two so-called forward models in the inversion algorithm: fire dynamics simulator (FDS) and the consolidated model of fire and smoke transport (CFAST). The fires in this work have peak HRRs ranging from 200 kW to 400 kW. It was found that FDS outperformed CFAST as a forward model at the expense of increased computational cost and that the error in the inverse reconstruction of a 400 kW steady fire was on par with room-scale oxygen consumption calorimetry.

Influence of grammage on heat release rate of polypropylene fabrics

2017 ◽  
Vol 36 (1) ◽  
pp. 30-46 ◽  
Author(s):  
Nicolas Hernandez ◽  
Rodolphe Sonnier ◽  
Stéphane Giraud
Keyword(s):  
Heat Flux ◽  
Growth Rate ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Cone Calorimeter ◽  
Heat Fluxes ◽  
Fire Growth ◽  
Time To Ignition ◽  
Moderate Change

The flammability of nine polypropylene fabrics or sheets has been tested using cone calorimeter at various heat fluxes (25, 35, 50, and 75 kW/m2) in order to assess the relevance of this fire test for thermally thin materials. The chosen procedure uses a grid and allows maintaining a constant exposed surface during the test, except for the lightest fabric. The structure of the knitted fabrics has a relatively small influence on the main flammability parameters. On the contrary, the area density of the sample (from 218 to 5729 g/m2) impacts strongly the time to ignition, the peak of heat release rate, and the increase in heat release rate after ignition (fire growth rate). At a fixed heat flux, thicker is the sample, higher are the time to ignition and the peak of heat release rate and lower is the fire growth rate. Moreover, thick samples exhibit the highest sensitivity of peak of heat release rate and the lowest sensitivity of fire growth rate to heat flux. This study emphasizes the fact that a moderate change in weight may have a significant influence on cone calorimeter results, without any significance on real flammability.

Cone Calorimeter Analysis on the Fire-Resistant Properties of FRW Fire-Retardant Particleboard

2011 ◽  
Vol 311-313 ◽  
pp. 2142-2145 ◽  
Author(s):  
Ying Tao Liu
Keyword(s):  
Heat Flux ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Cone Calorimeter ◽  
Fire Retardant ◽  
Total Heat ◽  
Total Heat Release ◽  
High Increase

The fire-resistant properties of FRW fire-retardant particleboard and untreated particleboard had been measured under a heat flux of 75 kW/m2 by cone calorimeter (CONE). Through the compare between FRW fire-retardant particleboard and untreated particleboard, the influence on the particleboard by FRW fire retardant had been indicated. The results showed that the indexes of heat release rate (HRR), total heat release (THR) and efficient heat combustion (EHC) etc of FRW fire-retardant particleboard were obviously reduced contrast to the ordinary particleboard, but the char-forming rate had a high increase.

DNS of Flame-Wall Interaction and Heat Transfer in a Constant Volume Vessel

2010 ◽  
Author(s):  
Akihiko Tsunemi ◽  
Yoshihiro Horiko ◽  
Masayasu Shimura ◽  
Naoya Fukushima ◽  
Seiji Yamamoto ◽  
...  
Keyword(s):  
Heat Flux ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Burning Velocity ◽  
Fluid Velocity ◽  
Pressure Rise ◽  
Kinetic Mechanism ◽  
Constant Volume ◽  
Wall Interaction

Direct numerical simulations of turbulent hydrogen/air and methane/air premixed flames in a rectangular constant volume vessel have been conducted with considering detailed kinetic mechanism to investigate flame behaviors and heat losses. For the hydrogen cases, since heat release rate increases with pressure rise due to dilatation during combustion in the constant vessel, heat flux on a wall also increases. For the methane cases, the pressure increase does not raise wall heat flux significantly because of the decrescence of heat release rate caused by thermo-chemical reaction near a wall. Pressure waves caused by wall reflection fluctuate flame propagation for the hydrogen flames. Flame displacement speed decreases remarkably at the moment when the pressure wave passes through flame fronts from unburnt side to burnt side. However, the turbulent burning velocity at that time does not decrease because of increases of fluid velocity normal to the flame fronts.

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