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 Downward Flame Spread over RPU Samples

2013 ◽  
Vol 328 ◽  
pp. 921-925
Author(s):  
Yuan Ming Wang ◽  
Yong Ming Zhang ◽  
Heng Ze Zhao ◽  
Lan Ming Zhao
Keyword(s):  
Flame Spread ◽  
Combustion Process ◽  
Flame Height ◽  
Pulsation Frequency ◽  
Insulation Material ◽  
Spread Rate ◽  
Energy Feedback ◽  
Flame Spread Rate ◽  
Sample Width ◽  
Downward Flame Spread

The combustion process of polymer is a complex coupling of energy feedback from flame to fuel surface with degradation of polymer. In this paper, a series of comparative laboratory-scale experiments were carried out to study the effect of sample width on downward flame spread over the rigid polyurethane (RPU) foam, a typical thermal insulation material. The variations of some important parameters such as flame height, pulsation frequency and flame spread rate were measured and analyzed. Results show that if the width fixed, the parameters mentioned above independent with time. If the width less than 25cm, the sample can not burn completely. With the expand of width, average flame height and flame spread rate present the same chang trend that increase first and then decrease and finally reach a steady state, flame pulsation frequency increases first and then decreases since sample width more than 20cm. The heat transfer from flame and pyrolysis zone to virgin region is proportional to the height of flame, and mainly dominated by radioactive regime.

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 Fire Spread Characteristics of Metal-Polyethylene Sandwich Panels

Buildings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 396
Author(s):  
Ru Zhou ◽  
Zhihao Chen ◽  
Yinke Fan ◽  
Zhengjiang Yu ◽  
Jianan Qian ◽  
...  
Keyword(s):  
Mass Loss ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Sandwich Panels ◽  
Fire Spread ◽  
Flame Height ◽  
Time Interval ◽  
Sample Length ◽  
Pulsation Frequency ◽  
Spread Rate

An experimental study was conducted to determine the characteristics of the flame spread and droplets of metal-polyethylene (PE) sandwich panels during combustion. The mass-loss rate, average flame height, temperature, and fire spread rate were investigated. The results showed that the fire spread rate, mass change of the droplets, average flame height, and temperature increased with an increase in the sample length, except for the mass loss rate of the 40 cm-long sample. The time interval between the droplets decreased, and the flame pulsation frequency increased. The relationship between the flame height and sample length was determined. During the combustion process, bending deformation and top flame phenomena occurred due to the shrinkage of the PE, which increased the fire risk. The distance between the outer surface of the expanded metal aluminum layer and the insulation panel increased with an increase in the panel length. A schematic diagram of the fire spread of the metal sandwich panel was established based on the observations and theoretical analysis. The mechanism and combustion behavior of the metal sandwich panels were determined to provide references for the construction of metal sandwich panels of exterior walls.

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.

Experimental study of moisture content effects on horizontal flame spread over thin cotton fabric

2018 ◽  
Vol 89 (15) ◽  
pp. 3189-3200 ◽  
Author(s):  
Yunji Gao ◽  
Guoqing Zhu ◽  
Hui Zhu ◽  
Weiguang An ◽  
Yu Xia
Keyword(s):  
Moisture Content ◽  
Cotton Fabric ◽  
Flame Spread ◽  
Extreme Values ◽  
Ignition Time ◽  
Convective Heat Transfer Coefficient ◽  
Flame Height ◽  
Spread Rate ◽  
Untreated Cotton ◽  
Flame Spread Rate

In this paper, moisture content effects on horizontal flame spread were experimentally investigated using 0.245 mm thick, 28 cm tall and 28 cm wide untreated cotton fabric sheets with various moisture contents varying from 0 to 34%. The pyrolysis spread rates, flame heights and ignition times were obtained and analyzed. The corresponding results are as follows: as moisture content increases, the flame height and spread rate first increase and then decrease. In contrast, the ignition time shows an opposite trend with moisture content. The extreme values are observed in cases of 2% moisture content samples. Moreover, the flame spread rate in the warp direction is larger than that in the weft direction. For horizontal flame spread, the moisture content has the effect of consuming part of the heat feedback, which can play a role in reducing the flame spread rate; simultaneously, the moisture content can enlarge flame size and increase the convective heat transfer coefficient, thereby resulting in an increase in flame spread rate. The non-monotonous trend in pyrolysis spread rate is the result of competition between these effects.

scholarly journals Effect of Sample Width on Flame Spread Rate over a Thin Material in Microgravity

2009 ◽  
Vol 7 (ists26) ◽  
pp. Ph_61-Ph_66 ◽  
Author(s):  
Shuhei TAKAHASHI ◽  
Yasunori SEKI ◽  
Tadayoshi IHARA ◽  
Kazunori WAKAI ◽  
Subrata BHATATCHARJEE
Keyword(s):  
Flame Spread ◽  
Spread Rate ◽  
Flame Spread Rate ◽  
Sample Width

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.

Sign in / Sign up

Export Citation Format

Share Document