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.

Observations of energy transport and rate of spreads from low-intensity fires in longleaf pine habitat – RxCADRE 2012

2016 ◽  
Vol 25 (1) ◽  
pp. 76 ◽  
Author(s):  
B. Butler ◽  
C. Teske ◽  
D. Jimenez ◽  
J. O'Brien ◽  
P. Sopko ◽  
...  
Keyword(s):  
Total Energy ◽  
Energy Transport ◽  
Wildland Fire ◽  
Ground Level ◽  
Radiative Energy ◽  
Convective Heating ◽  
Emissive Power ◽  
Rate Of Spread ◽  
Heating And Cooling ◽  
Air Temperatures

Wildland fire rate of spread (ROS) and intensity are determined by the mode and magnitude of energy transport from the flames to the unburned fuels. Measurements of radiant and convective heating and cooling from experimental fires are reported here. Sensors were located nominally 0.5 m above ground level. Flame heights varied from 0.3 to 1.8 m and flaming zone depth varied from 0.3 to 3.0 m. Fire ROS derived from observations of fire transit time between sensors was 0.10 to 0.48 m s–1. ROS derived from ocular estimates reached 0.51 m s–1 for heading fire and 0.25 m s–1 for backing fire. Measurements of peak radiant and total energy incident on the sensors during flame presence reached 18.8 and 36.7 kW m–2 respectively. Peak air temperatures reached 1159°C. Calculated fire radiative energy varied from 7 to 162 kJ m–2 and fire total energy varied from 3 to 261 kJ m–2. Measurements of flame emissive power peaked at 95 kW m–2. Average horizontal air flow in the direction of flame spread immediately before, during, and shortly after the flame arrival reached 8.8 m s–1, with reverse drafts of 1.5 m s–1; vertical velocities varied from 9.9 m s–1 upward flow to 4.5 m s–1 downward flow. The observations from these fires contribute to the overall understanding of energy transport in wildland fires.

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 Facilitating Prescribed Fire in Northern California through Indigenous Governance and Interagency Partnerships

Fire ◽  
2021 ◽  
Vol 4 (3) ◽  
pp. 37
Author(s):  
Tony Marks-Block ◽  
William Tripp
Keyword(s):  
Political Ecology ◽  
Prescribed Fire ◽  
Prescribed Burning ◽  
Participant Observation ◽  
Fire Suppression ◽  
The United States ◽  
Northern California ◽  
Prescribed Burn ◽  
California Department ◽  
State Regulations

Prescribed burning by Indigenous people was once ubiquitous throughout California. Settler colonialism brought immense investments in fire suppression by the United States Forest Service and the California Department of Forestry and Fire Prevention (CAL FIRE) to protect timber and structures, effectively limiting prescribed burning in California. Despite this, fire-dependent American Indian communities such as the Karuk and Yurok peoples, stalwartly advocate for expanding prescribed burning as a part of their efforts to revitalize their culture and sovereignty. To examine the political ecology of prescribed burning in Northern California, we coupled participant observation of prescribed burning in Karuk and Yurok territories (2015–2019) with 75 surveys and 18 interviews with Indigenous and non-Indigenous fire managers to identify political structures and material conditions that facilitate and constrain prescribed fire expansion. Managers report that interagency partnerships have provided supplemental funding and personnel to enable burning, and that decentralized prescribed burn associations facilitate prescribed fire. However, land dispossession and centralized state regulations undermine Indigenous and local fire governance. Excessive investment in suppression and the underfunding of prescribed fire produces a scarcity of personnel to implement and plan burns. Where Tribes and local communities have established burning infrastructure, authorities should consider the devolution of decision-making and land repatriation to accelerate prescribed fire expansion.

The Geographical Distribution and Seasonality of Persistence in Monthly Mean Air Temperatures over the United States

1986 ◽  
Vol 114 (3) ◽  
pp. 546-560 ◽  
Author(s):  
H. M. van den Dool ◽  
W. H. Klein ◽  
J. E. Walsh
Keyword(s):  
United States ◽  
Geographical Distribution ◽  
The United States ◽  
Air Temperatures

Mechanisms Contributing to the Warming Hole and the Consequent U.S. East–West Differential of Heat Extremes

2012 ◽  
Vol 25 (18) ◽  
pp. 6394-6408 ◽  
Author(s):  
Gerald A. Meehl ◽  
Julie M. Arblaster ◽  
Grant Branstator
Keyword(s):  
United States ◽  
Twentieth Century ◽  
Linear Trend ◽  
Coupled Model ◽  
The United States ◽  
Convective Heating ◽  
Central Pacific ◽  
Southeastern Part ◽  
Climate System Model ◽  
East West

Abstract A linear trend calculated for observed annual mean surface air temperatures over the United States for the second-half of the twentieth century shows a slight cooling over the southeastern part of the country, the so-called warming hole, while temperatures over the rest of the country rose significantly. This east–west gradient of average temperature change has contributed to the observed pattern of changes of record temperatures as given by the ratio of daily record high temperatures to record low temperatures with a comparable east–west gradient. Ensemble averages of twentieth-century climate simulations in the Community Climate System Model, version 3 (CCSM3), show a slight west–east warming gradient but no warming hole. A warming hole appears in only several ensemble members in the Coupled Model Intercomparison Project phase 3 (CMIP3) multimodel dataset and in one ensemble member of simulated twentieth-century climate in CCSM3. In this model the warming hole is produced mostly from internal decadal time-scale variability originating mainly from the equatorial central Pacific associated with the Interdecadal Pacific Oscillation (IPO). Analyses of a long control run of the coupled model, and specified convective heating anomaly experiments in the atmosphere-only version of the model, trace the forcing of the warming hole to positive convective heating anomalies in the central equatorial Pacific Ocean near the date line. Cold-air advection into the southeastern United States in winter, and low-level moisture convergence in that region in summer, contribute most to the warming hole in those seasons. Projections show a disappearance of the warming hole, but ongoing greater surface temperature increases in the western United States compared to the eastern United States.

scholarly journals Extremal Dependence between Temperature and Ozone over the Continental U.S.

2017 ◽  
Author(s):  
Pakawat Phalitnonkiat ◽  
Wenxiu Sun ◽  
Mircea D. Grigoriu ◽  
Peter G. M. Hess ◽  
Gennady Samorodnitsky ◽  
...  
Keyword(s):  
Climate Model ◽  
Heat Waves ◽  
Strong Dependence ◽  
Measurement Data ◽  
The United States ◽  
Value Theory ◽  
Temperature Extremes ◽  
Measured Temperature ◽  
Extremal Dependence ◽  
Year 2000

Abstract. The co-occurrence of heat waves and pollution events and the resulting high mortality rates emphasizes the importance of the co-occurrence of pollution and temperature extremes. Through the use of extreme value theory and other statistical methods ozone and temperature extremes and their joint occurrence are analyzed over the United States during the summer months (JJA) using Clean Air Status and Trends Network (CASTNET) measurement data and simulations of the present and future climate and chemistry in the Community Earth System Model (CESM1) CAM4-chem. Three simulations using CAM4-chem were analyzed: the Chemistry Climate Model Initiative (CCMI) reference experiment using specified dynamics (REFC1SD) between 1992–2010, a 25-year present-day simulation branched off the CCMI REFC2 simulation in the year 2000 and a 25-year future simulation branched off the CCMI REFC2 simulation in 2100. The latter two simulations differed in their concentration of carbon dioxide (representative of the years 2000 and 2100) but were otherwise identical. A new metric is developed to measure the joint extremal dependence of ozone and temperature by evaluating the spectral dependence of their extremes. Two regions of the U.S. give the strongest measured extreme dependence of ozone and temperature: the northeast and the southeast. The simulations do not capture the relationship between temperature and ozone over the northeast but do simulate a strong dependence of ozone on extreme temperatures over the southeast. In general, the simulations of ozone and temperature do not capture the width of the measured temperature and ozone distributions. While on average the future increase in the 90th percentile temperature and the 90th percentile ozone slightly exceed the mean increase over the continental U.S., in many regions the width of the temperature and ozone distributions decrease. The location of future increases in the tails of the ozone distribution are weakly related to those of temperature with a correlation of 0.3.

Improved Design of Vertical Curves with Sight Distance Profiles

2003 ◽  
Vol 1851 (1) ◽  
pp. 13-24 ◽  
Author(s):  
Yasser Hassan
Keyword(s):  
Design Procedure ◽  
The United States ◽  
Analytical Models ◽  
Minimum Length ◽  
Vertical Alignment ◽  
The Road ◽  
Sight Distance ◽  
Special Cases ◽  
Current Design ◽  
Improved Design

Design of vertical alignment is one of the main tasks in highway geometric design. This task requires, among other things, that the designer ensure drivers always have a clear view of the road so they can stop before hitting an unexpected object in the road. Therefore, the ability to determine the required and available stopping sight distance (SSD) at any point of the vertical alignment is essential for the design process. Current design guides in the United States and Canada provide simple analytical models for determining the minimum length of a vertical curve that would satisfy the sight distance requirement. However, these models ignore the effect of grade on the required SSD. Alternative approaches and models have also been suggested but cover only special cases of vertical curves. Two specific models were expanded to determine the required SSD on crest and sag vertical curves. By comparing profiles of available SSD and required SSD on examples of vertical curves, it was shown that current North American design practices might yield segments of the vertical curve where the driver’s view is constrained to a distance shorter than the required SSD. An alternative design procedure based on the models was developed and used to determine the minimum lengths of crest and sag vertical curves. Depending on the approach grade, these new values of minimum curve length might be greater than or less than values obtained through conventional design procedures. Design aids were therefore provided in tabular form for designers’ easy and quick use.

scholarly journals Influence of the Meteorological Record Length on the Generation of Representative Weather Files

Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 2103
Author(s):  
Michele Libralato ◽  
Giovanni Murano ◽  
Alessandra De Angelis ◽  
Onorio Saro ◽  
Vincenzo Corrado
Keyword(s):  
Strong Dependence ◽  
Building Energy ◽  
Weather Data ◽  
Air Temperatures ◽  
Change Effect ◽  
Climate Change Effect ◽  
The Common ◽  
Energy Simulations ◽  
Heat And Moisture ◽  
Weather Record

Heat and moisture (HM) transfer simulations of building envelopes and whole building energy simulations require adequate weather files. The common approach is to use weather data of reference years constructed from meteorological records. The weather record affects the capability of representing the real weather of the resulting reference years. In this paper the problem of the influence of the length of the records on the representativeness of the reference years is addressed and its effects are evaluated also for the applicative case of the moisture accumulation risk analysis with the Glaser Method and with DELPHIN 6, confirming that records shorter than 10 years could lead to less representative reference years. On the other hand, it is shown that reference years obtained from longer periods are not representative of the most recent years, which present higher dry-bulb air temperatures due to a short-term climate change effect observed in all the considered weather records. An alternative representative year (Moisture Representative Year) to be used in building energy simulations with a strong dependence on moisture is presented.

The Homelessness Crisis and Burn Injuries: A Cohort Study

2020 ◽  
Vol 41 (4) ◽  
pp. 820-827
Author(s):  
Sebastian Q Vrouwe ◽  
Maxwell B Johnson ◽  
Christopher H Pham ◽  
Christianne J Lane ◽  
Warren L Garner ◽  
...  
Keyword(s):  
Cohort Study ◽  
Los Angeles ◽  
Burn Injury ◽  
The United States ◽  
High Risk Population ◽  
University Of Southern California ◽  
Call To Action ◽  
Burn Prevention ◽  
Stable Housing ◽  
Using Data

Abstract The United States is facing a growing homelessness crisis. We characterize the demographics and outcomes of homeless patients who sustain burn injury and compare them to a cohort of domiciled patients. A retrospective cohort study was performed at the Los Angeles County + University of Southern California Regional Burn Center for consecutive acute burn admissions in adults from June 1, 2015, to December 31, 2018. Patients were categorized as either domiciled or homeless at the time of their injury. Prevalence rates were estimated using data from the regional homeless count. From 881 admissions, 751 (85%) had stable housing and 130 (15%) were homeless. The rate of burn injury requiring hospitalization for homeless adults was estimated at 88 per 100,000 persons. Homeless patients had a significantly larger median burn size (7 vs 5%, P < .05) and a greater rate of flame burns (68 vs 42%, P < .001). For the homeless, rates of assault and self-inflicted injury were 4- (18 vs 4%, P < .001) and 2-fold higher (9 vs 4%, P < .001), respectively. Homeless patients had higher rates of mental illness (32 vs 12%, P < .001) and substance abuse (88 vs 22%, P < .001), and were less likely to follow-up as outpatients (54 vs 87%, P < .001). There was no difference in mortality. Homeless patients had a longer median length of stay (LOS; 11 vs 7 days, P < .001) without significant differences in LOS per percentage TBSA. Homeless individuals should be considered a high-risk population for burn injury. This distinction serves as a call to action for the development of burn prevention strategies.

The Footprint of Urban Areas on Global Climate as Characterized by MODIS

2005 ◽  
Vol 18 (10) ◽  
pp. 1551-1565 ◽  
Author(s):  
Menglin Jin ◽  
Robert E. Dickinson ◽  
Da Zhang
Keyword(s):  
Land Cover ◽  
Skin Temperature ◽  
Urban Areas ◽  
Climate Models ◽  
Global Analysis ◽  
The United States ◽  
Climate Impact ◽  
Surface Temperatures ◽  
Air Temperatures ◽  
Seasonal And Diurnal Variations

Abstract One mechanism for climate change is the collected impact of changes in land cover or land use. Such changes are especially significant in urban areas where much of the world’s population lives. Satellite observations provide a basis for characterizing the physical modifications that result from urbanization. In particular, the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument on the National Aeronautics and Space Administration (NASA) Terra satellite measures surface spectral albedos, thermal emissivities, and radiative temperatures. A better understanding of these measurements should improve our knowledge of the climate impact of urbanization as well as our ability to specify the parameters needed by climate models to compute the impacts of urbanization. For this purpose, it is useful to contrast urban areas with neighboring nonurban surfaces with regard to their radiative surface temperatures, emissivities, and albedos. Among these properties, surface temperatures have been most extensively studied previously in the context of the “urban heat island” (UHI). Nevertheless, except for a few detailed studies, the UHI has mostly been characterized in terms of surface air temperatures. To provide a global analysis, the zonal average of these properties are presented here measured over urban areas versus neighboring nonurban areas. Furthermore, individual cities are examined to illustrate the variations of these variables with land cover under different climate conditions [e.g., in Beijing, New York, and Phoenix (a desert city of the United States)]. Satellite-measured skin temperatures are related to the surface air temperatures but do not necessarily have the same seasonal and diurnal variations, since they are more coupled to surface energy exchange processes and less to the overlying atmospheric column. Consequently, the UHI effects from skin temperature are shown to be pronounced at both daytime and nighttime, rather than at night as previously suggested from surface air temperature measurements. In addition, urban areas are characterized by albedos much lower than those of croplands and deciduous forests in summer but similar to those of forests in winter. Thus, urban surfaces can be distinguished from nonurban surfaces through use of a proposed index formed by multiplying skin temperature by albedo.

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