scholarly journals Comparison of Fire Behaviors of Thermally Thin and Thick Rubber Latex Foam under Bottom Ventilation

Polymers ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 88
Author(s):  
Qi Yuan ◽  
Dongmei Huang ◽  
Yiwei Hu ◽  
Liming Shen ◽  
Long Shi ◽  
...  
Keyword(s):  
Flame Spread ◽  
Mass Loss Rate ◽  
Fire Risk ◽  
Flame Height ◽  
Maximum Temperature ◽  
Small Scale ◽  
Rubber Latex ◽  
Rate Maximum ◽  
The One ◽  
Maximum Mass Loss

Fire behaviors of rubber latex foam under different thickness conditions (d = 1, 2, and 5 cm) were explored by using a self-built small-scale experimental platform. It can be shown that the flame spread menchanism of thermally thin and thermally thick rubber latex foam is different. Rubber latex foam with a thickness of 2 cm shows higher fire risk, whose value of flame spread rate, maximum flame height, maximum mass loss rate, and maximum temperature are 2.93 × 10−3 m/s, 851.88 mm, and 1.83 g/s, 948.00 °C, respectively. On the one hand, this may due to the different mechanisms of flame spread, resulting in different preheating zones on the surface. On the other hand, this may because the thickness of residue formed by thermally thick materials is larger than the thin ones, obstructing the contact of the rubber latex foam with fresh air. In addition, a special phenomenon is noticed during the stage II, where the bottom unburned zone is located in the four edges (thermally thin material) and middle player (thermally thick material).

scholarly journals Comparison of Fire Behavior of Thermally Thin and Thick Latex Foam Under Bottom Ventilation

2018 ◽  
Author(s):  
Qi Yuan ◽  
Dongmei Huang ◽  
Yiwei Hu ◽  
Liming Shen ◽  
Long Shi ◽  
...  
Keyword(s):  
Natural Rubber ◽  
Flame Spread ◽  
Mass Loss Rate ◽  
Fire Behavior ◽  
Natural Rubber Latex ◽  
Fire Risk ◽  
Flame Height ◽  
Maximum Temperature ◽  
Small Scale ◽  
Rubber Latex

Fire behavior of natural rubber latex foam under different thickness conditions(d=1,2and 5cm)were explored though a little of experiments by using the self-built small scale experimental platform. It can be shown that the flame spread law of thermally thin and thermally thickness are different. Natural rubber latex foam with thickness of 2cm show higher fire risk, which value of flame spread rate, maximum flame height, maximum mass loss rate and maximum temperature is 0.00293m/s, 851.875mm, 1.83g/s, 948K,repectively.That may because the thickness of residue formed of thermally thick materials is larger than the thin one, obstructing the contact of the natural rubber latex foam with fresh air .In addition, a special phenomenon is noticed that during the second stage, the bottom unburned zone located in the four edges(thermally thin material) and middle player(thermally thick material).

scholarly journals Thermodynamic and Kinetic Characteristics of Combustion of Discrete Polymethyl Methacrylate Plates with Different Spacings in Concave Building Facades

Polymers ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 167
Author(s):  
Weiguang An ◽  
Lujun Peng ◽  
Minglun Cai ◽  
Kaiyang Hu ◽  
Song Li ◽  
...  
Keyword(s):  
Polymethyl Methacrylate ◽  
Flame Spread ◽  
Structure Factor ◽  
Turning Point ◽  
Fire Risk ◽  
Flame Height ◽  
Hazard Evaluation ◽  
Spread Rate ◽  
Building Facades ◽  
Flame Spread Rate

Polymethyl methacrylate plates are widely applied to buildings, producing significant fire hazards. It lacks a theoretical basis for the fire risk assessment of polymethyl methacrylate in concave building facades. Therefore, experimental methods are used to investigate combustion characteristics of discrete polymethyl methacrylate plates in a concave building facade. Influences of fuel coverage and structure factor are investigated, which is scant in previous works. When structure factor is invariable, average flame height increases first and then decreases as fuel coverage increases, and the turning point is between 0.64 and 0.76. In total, three different patterns of pyrolysis front propagation are first observed for different fuel coverages. Flame spread rate first increases and then decreases as fuel coverage rises, and the turning point is also between 0.64 and 0.76. When fuel coverage is invariable, the flame spread rate first increases and then decreases with increasing structure factor, and the turning point is 1.2. A model for predicting the flame spread rate of discrete polymethyl methacrylate is also developed. The predicted values are consistent with experimental results. Fuel spread rate of discrete polymethyl methacrylate rises as the fuel coverage increases. The above results are beneficial for thermal hazard evaluation and fire safety design of polymethyl methacrylate used in buildings.

Effect of Sample Width on Downward Flame Spread over Typical Energy Conservation Material at a High Elevation Area

2014 ◽  
Vol 664 ◽  
pp. 199-203 ◽  
Author(s):  
Wei Guang An ◽  
Lin Jiang ◽  
Jin Hua Sun ◽  
K.M. Liew
Keyword(s):  
Mass Loss ◽  
Flame Spread ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
High Elevation ◽  
Flame Height ◽  
Spread Rate ◽  
Flame Spread Rate ◽  
Sample Width ◽  
Downward Flame Spread

An experimental study on downward flame spread over extruded polystyrene (XPS) foam at a high elevation is presented. The flame shape, flame height, mass loss rate and flame spread rate were measured. The influences of width and high altitude were investigated. The flame fronts are approximately horizontal. Both the intensity of flame pulsation and the average flame height increase with the rise of sample width. The flame spread rate first drops and then rises with an increase in width. The average flame height, mass loss rate and flame spread rate at the higher elevation is smaller than that at a low elevation, which demonstrates that the XPS fire risk at the higher elevation area is lower. The experimental results agree well with the theoretical analysis. This work is vital to the fire safety design of building energy conservation system.

Effect of Sample Width on Characteristics of Flame Spread across Eucalyptus Wood Surface

2013 ◽  
Vol 401-403 ◽  
pp. 767-770
Author(s):  
Gui Hong Wu ◽  
Yi Qiang Wu ◽  
Yun Chu Hu ◽  
Xiao Dan Zhu
Keyword(s):  
Mass Loss ◽  
Flame Spread ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Flame Height ◽  
Spread Rate ◽  
Eucalyptus Wood ◽  
Flame Spread Rate ◽  
Sample Width ◽  
The Relationship

To study the effect of sample width on flame spread characteristics, a series of laboratory-scale experiments were conducted employing eucalyptus wood with width from 3 to 7 cm. Flame dimension, flame spread rate and mass loss rate were obtained. The relationship between these flame spread characteristics and sample width was explored. Both the dimensionless average flame height and depth vary as the-n power of sample width. With the increase of sample width, both the flame spread rate and mass loss rate first decrease and then rise. The minimum values appear when sample width measures 6 cm.

Experimental Study on Downward Flame Spread across XPS Surface

2013 ◽  
Vol 753-755 ◽  
pp. 445-451
Author(s):  
Wei Guang An ◽  
Hua Hua Xiao ◽  
Jin Hua Sun ◽  
Wei Gang Yan ◽  
Yang Zhou ◽  
...  
Keyword(s):  
Mass Loss ◽  
Flame Spread ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Flame Height ◽  
Spread Rate ◽  
Flame Spread Rate ◽  
Stage 1 ◽  
Exponential Change ◽  
Downward Flame Spread

To study downward flame spread across XPS surface, a series of laboratory-scale experiments were conducted. Typical flame spread characteristics were obtained. The flame spread process comprises four stages. There are twice accelerations during flame spread. The influence of maximum flame height on flame spread rate is not significant. The predicted flame spread rate utilizing mass loss rate is lower than the measured value. Three stages: increasing stage, stable stage and decreasing stage are observed in both change of maximum flame height and flame area. The changing trend of mass loss rate is similar to that of maximum flame height. For stage 1 and stage 3, exponential change of mass loss rate with time is found. The mass loss rate is constant for stage 2. The heat flux to the preheating zone is higher than that to surrounding environment. Experimental results agree well with theoretical analysis.

Experimental investigation of fire propagation in single live shrubs

2017 ◽  
Vol 26 (1) ◽  
pp. 58 ◽  
Author(s):  
Jing Li ◽  
Shankar Mahalingam ◽  
David R. Weise
Keyword(s):  
Wind Speed ◽  
Mass Loss ◽  
Bulk Density ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Flame Height ◽  
Maximum Mass ◽  
Gas Temperature ◽  
Fire Behaviour ◽  
Maximum Mass Loss

This work focuses broadly on individual, live shrubs and, more specifically, it examines bulk density in chaparral and its combined effects with wind and ignition location on the resulting fire behaviour. Empirical functions to predict bulk density as a function of height for 4-year-old chaparral were developed for two typical species of shrub fuels in southern California, USA, namely chamise (Adenostoma fasciculatum Hook & Arn.) and manzanita (Arctostaphylos spp. Adans.). Fuel beds of chamise foliage and small-diameter branches were burned in an open-topped wind tunnel. Three levels of bulk density, two ignition locations and two wind speeds were examined, focusing on overall fire behaviour. Mean maximum mass loss rate, elapsed time at which maximum mass loss rate occurred, flame height, flame angle, peak gas temperature and its peak change rate were measured. The mean maximum mass loss rate was not significantly affected by wind speed, ignition location, bulk density or moisture content. Both wind speed and ignition location significantly affected the time that maximum mass loss rate occurred. Only wind speed affected flame height and flame angle. The peak gas temperature within the shrub burning area was found to be mostly affected by the bulk density.

scholarly journals Fire Risk Analysis on Buildings Considering Fire Spread and Total Floor Area

2021 ◽  
Vol 21 (6) ◽  
pp. 141-148
Author(s):  
Seunghyeon Jin ◽  
Byeongheun Lee ◽  
Hyewon Kim ◽  
Inhyuk Koo ◽  
Youngjin Kwon ◽  
...  
Keyword(s):  
Risk Analysis ◽  
Flame Spread ◽  
Fire Risk ◽  
Fire Spread ◽  
Small Scale ◽  
Frequency Of Occurrence ◽  
Recreational Facilities ◽  
Floor Area ◽  
Fire Risk Analysis ◽  
Analysis Models

Fire risk analysis models utilized for the fire risk assessment of domestic structures do not usually take into account flame spread and building size. Therefore, in this study, the effect of the building size on flame spread was investigated. Results showed that the frequency of occurrence of fires increased when the building has 11 or more floors. Additionally, the rate of occurrence of small-scale fires also increased when the total floor area was greater than or equal to 1,000 m2. From the risk analysis, the fire risk of health care, medical, and recreational facilities were calculated to be 25.7 × 10-3, 4.29 × 10-3, and 0.91 × 10-3 persons per year, respectively. As such, these were classified as high-risk facilities.

Experimental Study on Downward Flame Spread of Rigid Polyurethane Foam with External Radiation

2014 ◽  
Vol 664 ◽  
pp. 194-198 ◽  
Author(s):  
Xin Ma ◽  
Ran Tu ◽  
Yan Li Zhao ◽  
Nan Wang ◽  
Qi Yuan Xie
Keyword(s):  
Flame Spread ◽  
Mass Loss Rate ◽  
Building Energy ◽  
Flame Height ◽  
External Radiation ◽  
Spread Rate ◽  
Radiation Heat ◽  
Building Energy Conservation ◽  
Building Insulation ◽  
Flame Spread Rate

Research on building insulation materials and their safety is an important topic in the field of building energy conservation. The objective of this paper is to analyze the coupling effects of the width and external radiation on the downward RPU foam flame spread characteristics. The most important flame characteristics including flame height, mass loss rate, flame spread rate were studied experimentally. The results suggest that with increasing external radiation levels, flame spread rate was larger. Under the condition of the external radiation heat flux exceeds a critical level, the RPU foam would be deformed and detached from the board when the flame spread to a certain distance. It also leads to a much higher flame height due to sufficient combustion. Additionally, the flame propagation firstly accelerated when it reaches to a certain distance and then becomes a stable subject to the preheating of the external radiation heat resource.

scholarly journals Experimental Study on Flammability and Flame Spread Characteristics of Polyvinyl Chloride (PVC) Cable

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2789
Author(s):  
Weiguang An ◽  
Yanhua Tang ◽  
Kai Liang ◽  
Tao Wang ◽  
Yang Zhou ◽  
...  
Keyword(s):  
Polyvinyl Chloride ◽  
Flame Spread ◽  
Fire Hazard ◽  
Flame Height ◽  
Maximum Temperature ◽  
Hazard Evaluation ◽  
Total Width ◽  
Spread Rate ◽  
Cable Structure ◽  
Flame Spread Rate

Polyvinyl chloride (PVC) is widely applied in cables as insulation materials, which are vital for operation and control of industrial processes. However, PVC cables fires frequently occur, arousing public concern. Therefore, experimental methods are used to study flammability and flame-spread characteristics of PVC cable in this paper. Influences of cable structure and number are investigated, which is scanty in previous works. As cable core number of single cable or cable number of multiple cables rises, average flame height and width increase while the increment decreases. Formulas concerning dimensionless flame height and single cable diameter (or total width of multiple cables) are obtained. The former is negatively correlated with the latter. For single cable, convective heat transfer is dominant, and flame-spread rate decreases as cable core number increases. Cable maximum temperature, which drops first and then rises as cable core number increases, is observed in the cable core area. For multiple cable, the flame-spread rate increases as cable number increases. As the cable number rises, the length of pyrolysis and combustion zone increases while the maximum temperature of cable surface decreases. This work is beneficial to fire hazard evaluation and safety design of PVC cables.

scholarly journals Analytical Determination of the Brake Temperature Mode During Repetitive Short-Term Braking

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1912
Author(s):  
Aleksander Yevtushenko ◽  
Katarzyna Topczewska ◽  
Michal Kuciej
Keyword(s):  
Friction Pair ◽  
Thermal Sensitivity ◽  
Finite Difference Methods ◽  
Temporal Variations ◽  
Frictional Heat ◽  
Maximum Temperature ◽  
Analytical Determination ◽  
Flash Temperature ◽  
Short Term ◽  
The One

An algorithm to determine the maximum temperature of brake systems during repetitive short-term (RST) braking mode has been proposed. For this purpose, the intermittent mode of braking was given in the form of a few cyclic stages consisting of subsequent braking and acceleration processes. Based on the Chichinadze’s hypothesis of temperature summation, the evolutions of the maximum temperature during each cycle were calculated as the sum of the mean temperature on the nominal contact surface of the friction pair elements and temperature attained on the real contact areas (flash temperature). In order to find the first component, the analytical solution to the one-dimensional thermal problem of friction for two semi-spaces taking into account frictional heat generation was adapted. To find the flash temperature, the solution to the problem for the semi-infinite rod sliding with variable velocity against a smooth surface was used. In both solutions, the temperature-dependent coefficient of friction and thermal sensitivity of materials were taken into account. Numerical calculations were carried out for disc and drum brake systems. The obtained temporal variations of sliding velocity, friction power and temperature were investigated on each stage of braking. It was found that the obtained results agree well with the corresponding data established by finite element and finite-difference methods.

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