scholarly journals Wildland firefighter safety zones: a review of past science and summary of future needs

2014 ◽  
Vol 23 (3) ◽  
pp. 295 ◽  
Author(s):  
B. W. Butler
Keyword(s):  
Burn Injury ◽  
Wildland Fire ◽  
Flame Temperature ◽  
Experimental Studies ◽  
Convective Heating ◽  
Radiant Heating ◽  
Atmospheric Conditions ◽  
Safety Zone ◽  
Flat Terrain ◽  
Firefighter Safety

Current wildland firefighter safety zone guidelines are based on studies that assume flat terrain, radiant heating, finite flame width, constant flame temperature and high flame emissivity. Firefighter entrapments and injuries occur across a broad range of vegetation, terrain and atmospheric conditions generally when they are within two flame heights of the fire. Injury is not confined to radiant heating or flat terrain; consequently, convective heating should be considered as a potential heating mode. Current understanding of energy transport in wildland fires is briefly summarised, followed by an analysis of burn injury mechanisms within the context of wildland fire safety zones. Safety zone theoretical and experimental studies are reviewed and a selection of wildland fire entrapments are examined within the context of safe separation distances from fires. Recommendations are made for future studies needed to more fully understand and define wildland firefighter safety zones.

scholarly journals Bridging the divide between fire safety research and fighting fire safely: how do we convey research innovation to contribute more effectively to wildland firefighter safety?

2017 ◽  
Vol 26 (2) ◽  
pp. 107 ◽  
Author(s):  
Theodore 'Ted' Adams ◽  
Bret W. Butler ◽  
Sara Brown ◽  
Vita Wright ◽  
Anne Black
Keyword(s):  
Fire Safety ◽  
Wildland Fire ◽  
Media Richness ◽  
Primary Research ◽  
Safety Zone ◽  
Policy Makers ◽  
Firefighter Safety ◽  
Safety Research ◽  
Getting Lost

Creating a safe workplace for wildland firefighters has long been at the centre of discussion for researchers and practitioners. The goal of wildland fire safety research has been to protect operational firefighters, yet its contributions often fall short of potential because much is getting lost in the translation of peer-reviewed results to potential and intended users. When information that could enhance safety is not adopted by individuals, the potential to improve safety – to decipher the wildland fire physical or social environment and to recognise hazards – is lost. We use firefighter safety-zone research as a case study to examine how primary research is, and could be, transferred to fire managers, policy-makers and firefighters. We apply four core communication theories (diffusion, translation, discourse and media richness) to improve knowledge transfer.

scholarly journals An empirically based approach to defining wildland firefighter safety and survival zone separation distances

2017 ◽  
Vol 26 (8) ◽  
pp. 655 ◽  
Author(s):  
Wesley G. Page ◽  
Bret W. Butler
Keyword(s):  
Burn Injury ◽  
Empirical Models ◽  
Flame Height ◽  
Fuel Type ◽  
Safety Zone ◽  
Fatal Injury ◽  
Firefighter Safety ◽  
Injury Model ◽  
The Us ◽  
Low Probability

Wildland firefighters in the US are mandated to identify areas that provide adequate separation between themselves and the flames (i.e. safety zones) to reduce the risk of burn injury. This study presents empirical models that estimate the distance from flames that would result in a low probability (1 or 5%) of either fatal or non-fatal injuries. The significant variables for the fatal injury model were fire shelter use, slope steepness and flame height. The separation distances needed to ensure no more than a 1 or 5% probability of fatal injury, without the use of a fire shelter, for slopes less than 25% were 20 to 50 m for flame heights less than 10 m, and 1 to 4 times the flame height for flames taller than 10 m. The non-fatal injury model significant variables were fire shelter use, vehicle use and fuel type. At the 1 and 5% probability thresholds for a non-fatal injury, without the use of a fire shelter, the separation distances were 1 to 2, 6 to 7, and 12 to 16 times greater than the current safety zone guideline (i.e. 4 times the flame height) for timber, brush and grass fuel types respectively.

Exploring fire response to high wind speeds: fire rate of spread, energy release and flame residence time from fires burned in pine needle beds under winds up to 27 ms−1

2020 ◽  
Vol 29 (1) ◽  
pp. 81
Author(s):  
Bret Butler ◽  
Steve Quarles ◽  
Christine Standohar-Alfano ◽  
Murray Morrison ◽  
Daniel Jimenez ◽  
...  
Keyword(s):  
Wind Speed ◽  
Energy Release ◽  
Residence Time ◽  
Wildland Fire ◽  
Ground Level ◽  
Fire Spread ◽  
Convective Heating ◽  
Atmospheric Conditions ◽  
Wind Speeds ◽  
Rate Of Spread

The relationship between wildland fire spread rate and wind has been a topic of study for over a century, but few laboratory studies report measurements in controlled winds exceeding 5ms−1. In this study, measurements of fire rate of spread, flame residence time and energy release are reported for fires burning under controlled atmospheric conditions in shallow beds of pine needles subject to winds ranging from 0 to 27ms−1 (measured 5m above ground level). The data suggested that under constant flow conditions when winds are less than 10ms−1, fire rate of spread increases linearly at a rate of ~3% of the wind speed, which generally agrees with other laboratory-based models. When wind speed exceeds 10ms−1, the fire rate of spread response to wind remains linear but with a much stronger dependence, spreading at a rate of ~13% of the wind speed. Radiative and convective heating correlated directly to wind speed, with radiant heating increasing approximately three-fold as much as convective heating over the range of winds explored. The data suggested that residence time is inversely related to wind speed and appeared to approach a lower limit of ~20s as wind exceeded 15ms−1. Average flame residence time over the range of wind speeds was nominally 26s.

Fire shelter performance in simulated wildfires: an exploratory study

2001 ◽  
Vol 10 (1) ◽  
pp. 29 ◽  
Author(s):  
Bret W. Butler ◽  
Ted Putnam
Keyword(s):  
Prescribed Fire ◽  
Burn Injury ◽  
Energy Levels ◽  
Strong Dependence ◽  
The United States ◽  
Convective Heating ◽  
Radiant Heating ◽  
Emissive Power ◽  
Air Temperatures ◽  
Current Design

Fire shelters are required equipment for most wildland firefighters in the United States. In this study we report flame emissive power and temperatures inside and outside fire shelters placed in one prescribed fire, five experimental field fires, and one laboratory fire. Energy levels radiated by flames varied from 70 to 150 kW m–2 and lasted less than 10 min. Maximum fire shelter internal air temperatures reached 250˚C and occurred during the test with the maximum external air temperatures (1000˚C). Air temperatures inside the fire shelters did not show a strong dependence on flame radiant power, rather they correlated most strongly with external air temperature. We compare measurements from these tests with results reported by others. The data clearly indicate (1) the capability of the fire shelter to protect the occupant from radiant heating; (2) the susceptibility of the current design to convective heating; and (3) the significant decrease in burn injury when fire shelters are used.

Experimental evidence for the role of ions in particle nucleation under atmospheric conditions

2006 ◽  
Vol 463 (2078) ◽  
pp. 385-396 ◽  
Author(s):  
Henrik Svensmark ◽  
Jens Olaf P Pedersen ◽  
Nigel D Marsh ◽  
Martin B Enghoff ◽  
Ulrik I Uggerhøj
Keyword(s):  
Sulphur Dioxide ◽  
Aerosol Particles ◽  
Experimental Studies ◽  
Negative Ion ◽  
Cloud Formation ◽  
Particle Nucleation ◽  
Atmospheric Conditions ◽  
Ion Density ◽  
Stable Clusters

Experimental studies of aerosol nucleation in air, containing trace amounts of ozone, sulphur dioxide and water vapour at concentrations relevant for the Earth's atmosphere, are reported. The production of new aerosol particles is found to be proportional to the negative ion density and yields nucleation rates of the order of 0.1–1 cm −3  s −1 . This suggests that the ions are active in generating an atmospheric reservoir of small thermodynamically stable clusters, which are important for nucleation processes in the atmosphere and ultimately for cloud formation.

Assessment of the Threat From Wildfires on Above Ground Natural Gas Facilities

2018 ◽  
Author(s):  
Clive G. Robinson ◽  
Zoë E. Wattis ◽  
Colin Dooley ◽  
Sladjana Popovic
Keyword(s):  
Information System ◽  
Natural Gas ◽  
Thermal Radiation ◽  
Vegetation Type ◽  
Wildland Fire ◽  
Flame Temperature ◽  
Pipeline System ◽  
Recent Experience ◽  
Tree Line ◽  
Fire Information

In the light of recent experience of wildfires in Alberta and British Columbia, Alliance Pipeline has strengthened their emergency preparedness in dealing with external fire events that have the potential to affect above-ground facilities connected with their high pressure natural gas pipeline system. As part of this initiative a quantitative methodology has been developed that enables the effects of a wildfire on an above-ground pipeline facility to be assessed. The methodology consists of three linked calculations which assess: 1. the severity of the wildfire, based on information from the Canadian Wildland Fire Information System, 2. the transmission of thermal radiation from the wildfire to the facility, and, 3. the response of equipment, structures and buildings to the incident thermal radiation. The predictions of the methodology agree well with the actual damage observed at a lateral block valve site following a wildfire in 2016. Application to example facility types (block valve sites, meter stations and compressor stations) has demonstrated that, in general, damage is only predicted for more vulnerable items such as cables. The sensitivity of the predictions of the methodology to the input parameters and key modelling uncertainties has been examined. This demonstrates that the results are sensitive to the distance of the facility from the tree line and the assumed vegetation type. This shows the importance of verifying the location relative to the vegetation and selecting the appropriate vegetation type from the Canadian Wildland Fire Information System for site specific assessments. The predictions of the methodology are particularly sensitive to the assumed flame temperature. However, a value has been chosen that gives good agreement with measured thermal radiation values from wildfires. Of the mitigation options considered, the most effective and practical is to increase the distance to the tree line. This measure has the advantage of reducing radiation levels for all items on the site. Even though the work shows that failure of exposed pipework due to wildfires is unlikely, maintaining the flow within pipes is recommended as this increases the radiative flux at which failure is predicted to occur. However, as failure of cables and hence control systems would occur at a lower flux levels the fail-safe actions of such systems needs to be confirmed. Shielding of cables or items of equipment in general is likely to be impractical but could be considered for particularly vulnerable equipment or locations.

Application of Generalized Regression Neural Network in Predicting the Performance of Natural Convection Solar Dryer

2019 ◽  
Vol 142 (3) ◽  
Author(s):  
M. Sridharan
Keyword(s):  
Neural Network ◽  
Natural Convection ◽  
Network Architecture ◽  
Experimental Studies ◽  
Generalized Regression Neural Network ◽  
Atmospheric Conditions ◽  
Time Duration ◽  
Transient Nature ◽  
Solar Dryer ◽  
Generalized Regression

Abstract The performance evaluation of a natural convection solar dryer is a complex one because of the transient and non-linear nature of atmospheric conditions. In this comparative study, a smart neural network -based tool was developed for estimating the performance of such a transient nature solar dryer. For this purpose, a series of experimental studies are conducted through four successive days and compared with the generalized regression neural network (GRNN) modeling. GRNN architecture proposed in this study consists of three inputs (time duration, irradiance, and ambient temperature) and four outputs (drying chamber temperature, the mass of moisture removed, drying rate, and dryer efficiency). Such generalized regression neural network architecture was trained, tested, and validated with real-time experimental variable data sets. The results of the GRNN model are in good agreement with experimental results. The overall accuracy of the proposed GRNN model in predicting the performance is 96.29%.

Biotechnological Approach To Preserve Fresh Pasta Quality

2017 ◽  
Vol 80 (12) ◽  
pp. 2006-2013 ◽  
Author(s):  
L. Angiolillo ◽  
A. Conte ◽  
M. A. del Nobile
Keyword(s):  
Production Process ◽  
Sensory Quality ◽  
Lactobacillus Reuteri ◽  
Experimental Studies ◽  
Nutrient Content ◽  
High Water ◽  
Atmospheric Conditions ◽  
Biotechnological Approach ◽  
Fresh Pasta

ABSTRACT Fresh pasta is highly susceptible to microbial contamination because of its high water activity and nutrient content. In this study, a new biopreservation system was examined that consists of an active sodium alginate solution containing Lactobacillus reuteri and glycerol, which was added during the production process of pasta. Our aim was to extend the fresh pasta shelf life by the in situ production of reuterin, thereby avoiding the use of thermal treatments that generally compromise food sensory characteristics. Two experimental studies were carried out with the product packaged under either ordinary or modified atmospheric conditions. Microbiological and sensory quality indices were monitored to determine the effectiveness of biopreservation on product quality during storage. The use of the active solution with L. reuteri and glycerol during the production process of pasta improved both microbial and sensory quality, particularly when combined with modified atmosphere.

Emission Characteristics of Syngas Flames

2006 ◽  
Author(s):  
Sibendu Som ◽  
Anita I. Ramirez ◽  
Suresh Aggarwal
Keyword(s):  
Power Generation ◽  
Flame Temperature ◽  
Chemical Kinetic ◽  
Inlet Temperature ◽  
No Production ◽  
Emission Characteristics ◽  
Atmospheric Conditions ◽  
Harmful Emission ◽  
Fundamental Understanding ◽  
Fuel Components

Synthesis gas or "Syngas" is being recognized as a viable energy source worldwide, particularly for stationary power generation due to its wide flexibility in fuel sources and superior pollutants characteristics. Although its composition may vary significantly, it generally contains CO and H2 as the dominant fuel components with varying amount of methane and diluents. There are, however, gaps in the fundamental understanding of syngas combustion and emissions, as most previous research has focused on flames burning individual fuel components such as H2 and CH4, rather than syngas mixtures. To ensure the environmental feasibility of syngas, the harmful emission, especially NOx, must comply with current and future regulations. In addition, the combustion of syngas occurs at elevated pressures and inlet temperatures. Most published research has considered the combustion of syngas constituents at atmospheric conditions. This paper presents a numerical investigation to gain fundamental understanding of combustion and emission characteristics of syngas with varying composition, pressure and inlet temperatures. Two representative syngas fuel mixtures, 50% H2/50% CO and 5% H2 / 95% CO (% vol.), are chosen based on fuel composition data from multiple power generation plants worldwide. Three detailed chemical kinetic models are used namely, GRI 3.0, Davis and Dryer mechanisms. Results indicate that for both representative mixtures an increase in reactant temperature leads to a significant increase in NOx due to increase in flame temperature caused by an increase in inlet temperature. As the pressure is increased from 1 to 6 atm, the peak NO increases rapidly, and then becomes nearly independent of pressure. This can be attributed to a similar trend in radical species responsible for NO production such as HCN and OH which both show the most significant increase at low pressures. The emission index for these flames is also found to follow a similar behavior with pressure.

Aerothermochemistry of Metal Erosion by Hot Reactive Gases

1978 ◽  
Vol 100 (3) ◽  
pp. 531-536 ◽  
Author(s):  
A. Gany ◽  
L. H. Caveny ◽  
M. Summerfield
Keyword(s):  
Surface Reactions ◽  
Experimental Studies ◽  
Heating Surface ◽  
Melting Rate ◽  
Short Exposure ◽  
Convective Heating ◽  
Erosion Rates ◽  
Diffusion Limited ◽  
O2 Concentration ◽  
Reactive Gases

Analytical studies were conducted to investigate the mechanisms of metal erosion produced by short exposures (< 2 ms) to flowing high pressure (∼ 350 MPa), high temperature (∼ 3000 K) reactive gases. Previous experimental studies established that the intense heating during the short exposure produced melting and, when reactive gases were used, oxidation of the surface and enhanced erosion. The reactions were modeled as diffusion-limited, heterogeneous surface reactions which achieved equilibrium at the gas/metal interface. Calculated results for the sequential events of initial heating, surface reactions, and melting explained and correlated the experimental trends for Fe, Al, Ti, and Mo. Rapidly increasing erosion rates with increasing O2 concentration are the result of the surface reactions between the metal and O2. As O2 concentration increases, the heating produced by the surface reaction exceeds the forced convective heating which, in turn, greatly enhances the melting rate.

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