Beyond “fire temperatures”: calibrating thermocouple probes and modeling their response to surface fires in hardwood fuels

2008 ◽  
Vol 38 (5) ◽  
pp. 1008-1020 ◽  
Author(s):  
Anthony S. Bova ◽  
Matthew B. Dickinson
Keyword(s):  
Fire Behavior ◽  
Calibration Method ◽  
Temperature Sensitive ◽  
Reporting Standard ◽  
Surface Fires ◽  
Standard Fire ◽  
Point Estimates ◽  
Measurement Devices ◽  
Maximum Temperatures ◽  
Fire Characteristics

The maximum temperatures of thermocouples, temperature-sensitive paints, and calorimeters exposed to flames in wildland fires are often called “fire temperatures” but are determined as much by the properties and deployment of the measurement devices as by the fires themselves. Rather than report device temperatures that are not generally comparable among studies, we show that maximum and time-integrated temperatures of relatively thick (4.8 mm diameter) type-K thermocouple probes (TCPs) can be calibrated to estimate fuel consumption and fire line intensity in surface fires. Although reporting standard fire characteristics is an improvement over reporting device temperatures, TCPs are not ideal instruments for monitoring surface fires, because they provide only point estimates of fire behavior and must be calibrated for different fire environments, TCP characteristics, and deployments. To illustrate how TCPs respond to fires and to point the way towards a more general calibration method, we report results from a numerical model that accurately simulated TCP response to a spreading surface fire.

A comparison of thermocouples and temperature paints to monitor spatial and temporal characteristics of landscape-scale prescribed fires

2004 ◽  
Vol 13 (3) ◽  
pp. 311 ◽  
Author(s):  
Louis R. Iverson ◽  
Daniel A. Yaussy ◽  
Joanne Rebbeck ◽  
Todd F. Hutchinson ◽  
Robert P. Long ◽  
...  
Keyword(s):  
Grid Point ◽  
Heat Index ◽  
Maximum Temperature ◽  
Fire Intensity ◽  
Temperature Sensitive ◽  
Burned Areas ◽  
Rate Of Spread ◽  
Maximum Temperatures ◽  
Highly Correlated ◽  
Fire Characteristics

A method to better monitor landscape-level fire characteristics is presented. Three study areas in southern Ohio oak-hickory (Quercus-Carya) forests were established with four treatment areas of ~20 ha each: control (C), burn only (B), thin only (T) or thin plus burn (TB). Two independent measures useful for qualitatively characterising fire intensity were established on a 50-m grid, resulting in over 120 sampling locations at each site, in the burned areas: aluminum tags painted with temperature-sensitive paints, and logger-probe units that logged probe temperature every 2 s during burns. Fires were conducted in spring 2001. The logger-probe units allowed five measures qualitatively related to fire intensity or timing to be calculated at each grid point: maximum probe temperature; duration of probe temperature above 30°C; a heat index, defined as the summed temperatures above 30°C; time of maximum temperature; and estimated rate of spread. Maximum temperatures recorded by the two measuring systems were highly correlated (r2 = 0.83). Relative to painted tags, logger-probe units provide information useful for assessing some other components of fire behaviour. The temporal recording of temperatures allowed us to prepare a web-based simulation of the fires. Heat index and rate of spread estimates provided additional fire information. The TB units consistently burned cooler than the B units, perhaps because of uncured slash and a disrupted fuel bed in those units.

THE TEMPERATURES OF SURFACE FIRES IN JACK PINE BARREN: I. THE VARIATION IN TEMPERATURE WITH TIME

1966 ◽  
Vol 44 (10) ◽  
pp. 1285-1292 ◽  
Author(s):  
David W. Smith ◽  
John H. Sparling
Keyword(s):  
Jack Pine ◽  
Maximum Temperature ◽  
Surface Fires ◽  
Mean Temperature ◽  
The Mean ◽  
Maximum Temperatures

The temperatures of 18 fires in an open jack pine barren near Timmins, Ontario, have been recorded. The maximum temperature recorded was 545 °C, although in other determinations fire temperatures in excess of 1000 °C were reached. The mean temperature of all fires was 340.6 ± 133.2 °C. Three fires at 230, 345, and 545 °C were considered in detail.The maximum temperature of a fire was normally recorded at heights of 5 cm or 10 cm above the surface. Maximum temperatures of hotter fires usually occurred at greater heights than cooler ones. Duration and the temperature ("intensity") of the fire are important aspects of fire studies.

Fire Behavior of Raw Earth Bricks: Influence of Water Content and Cement Stabilization

2022 ◽  
Author(s):  
Rafik Isaam Abdallah ◽  
Céline Perlot ◽  
Hélène Carré ◽  
Christian La Borderie ◽  
Haissam El Ghoche
Keyword(s):  
Water Content ◽  
Thermal Instability ◽  
Fire Behavior ◽  
Standard Fire ◽  
Influence Of Water ◽  
Cement Stabilization ◽  
The One ◽  
Raw Earth ◽  
Water Contents ◽  
Soil And Water

This study focus on the effects of both water content and cement stabilization on the fire behavior of earth bricks. To observe the effect of cement stabilization, two materials are formulated: raw earth with only soil and water, and stabilized bricks with soil, water and cement (3.5% by mass of soil). Since the material’s mechanical strength can strongly influence its fire behavior, the raw bricks were compacted at 50 MPa to reach a compressive strength similar to the one of stabilized bricks. Four different water contents were tested; dry state obtained with oven drying and three others achieved through equalization at 50%, 75% and 100% of relative humidities. Bricks are then subjected to an ISO 834-1 standard fire. Results show that water content has caused a thermal instability behavior on the raw earth bricks after equalization at 50% and 75% relative humidities. Thermally stable bricks displayed a noticeable diffusion of cracks on their heated face. Furthermore, cement stabilization helps to prevent from thermal instabilities.

Statistical Models of Key Components of Wildfire Risk

2019 ◽  
Vol 6 (1) ◽  
pp. 197-222 ◽  
Author(s):  
Dexen D.Z. Xi ◽  
Stephen W. Taylor ◽  
Douglas G. Woolford ◽  
C.B. Dean
Keyword(s):  
Fire Behavior ◽  
Fire Risk ◽  
Data Driven ◽  
Management Decision ◽  
Risk Modeling ◽  
Deterministic Models ◽  
Integrative Framework ◽  
Modeling Systems ◽  
Management Decision Making ◽  
Fire Characteristics

Fire danger systems have evolved from qualitative indices, to process-driven deterministic models of fire behavior and growth, to data-driven stochastic models of fire occurrence and simulation systems. However, there has often been little overlap or connectivity in these frameworks, and validation has not been common in deterministic models. Yet, marked increases in annual fire costs, losses, and fatality costs over the past decade draw attention to the need for better understanding of fire risk to support fire management decision making through the use of science-backed, data-driven tools. Contemporary risk modeling systems provide a useful integrative framework. This article discusses a variety of important contributions for modeling fire risk components over recent decades, certain key fire characteristics that have been overlooked, and areas of recent research that may enhance risk models.

Approach for Zero Defect Manufacturing: Geometric Calibration of Five-Axis Machine Tools for Blisk Manufacturing Process

2018 ◽  
Author(s):  
Tae Hun Lee ◽  
Jan Behrens ◽  
Sascha Gierlings ◽  
Christian Brecher
Keyword(s):  
Manufacturing Process ◽  
Turbine Blades ◽  
Calibration Method ◽  
Test Method ◽  
Machining Process ◽  
Critical Conditions ◽  
Geometric Calibration ◽  
Measurement Devices ◽  
Five Axis ◽  
Five Axes

Five-axis machining is a key technology of blisk manufacturing process. Blisks generally require high accuracy due to their high performance and safety-critical conditions. However, recent research show that the design of the blisks and turbine blades are getting more complex and require even higher accuracy. This leads also to the application of wide and rare area of movement axes of the machine. Thus, the machine accuracy has to be assured within the overall machine volume. The geometric accuracy demonstrates the base accuracy of the machine. This paper presents a geometric calibration method optimized for the axes movement area of blisk machining process. The accurate calibration of the five-axis machine tool is challenging and hardly possible due to limited error measurement of standard measurement devices. Some measurement methods enable complete calibration of the machine but with complex, time-consuming process and expensive measurement devices. Also, due to the rare axes travel, there is no standard calibration method for the blisk machining process. The calibration method in this paper is developed based on so called ‘R-test’ method. The machine and the errors are modelled mathematically for the measurement. An adapter is applied for the measurement of maximum axis positions. Automation units are developed for the full machine integration and automation of calibration procedure. With the developed method, the machine is calibrated from 130 μm to 10 μm in maximum measurement time of 90 minutes. The calibration quality is validated at an independent measurement position with continuous movement of the five axes.

scholarly journals Effects of Biomass Removal Treatments on Stand-Level Fire Characteristics in Major Forest Types of the Northern Rocky Mountains

2010 ◽  
Vol 25 (1) ◽  
pp. 34-41 ◽  
Author(s):  
Elizabeth D. Reinhardt ◽  
Lisa Holsinger ◽  
Robert Keane
Keyword(s):  
Ponderosa Pine ◽  
Rocky Mountains ◽  
Fire Behavior ◽  
Fire Effects ◽  
Forest Types ◽  
Prescribed Burns ◽  
Northern Rocky Mountains ◽  
Biomass Removal ◽  
Fuel Dynamics ◽  
Fire Characteristics

Abstract Removal of dead and live biomass from forested stands affects subsequent fuel dynamics and fire potential. The amount of material left onsite after biomass removal operations can influence the intensity and severity of subsequent unplanned wildfires or prescribed burns. We developed a set of biomass removal treatment scenarios and simulated their effects on a number of stands that represent two major forests types of the northern Rocky Mountains: lodgepole and ponderosa pine. The Fire and Fuels Extension to the Forest Vegetation Simulator was used to simulate effects including stand development, fire behavior, and fire effects prior to the biomass removal treatment and 1, 10, 30, and 60 years after the treatment. Analysis of variance was used to determine whether these changes in fuel dynamics and fire potential differed significantly from each other. Results indicated that fire and fuel characteristics varied within and between forest types and depended on the nature of the treatment, as well as time since treatment. Biomass removal decreased fire potential in the short term, but results were mixed over the long term.

Prediction of crown fire behavior in two stands of jack pine

1993 ◽  
Vol 23 (3) ◽  
pp. 442-449 ◽  
Author(s):  
C.E. Van Wagner
Keyword(s):  
Physical Theory ◽  
Fire Behavior ◽  
Jack Pine ◽  
Published Data ◽  
Critical Surface ◽  
Crown Fire ◽  
Spread Rate ◽  
Empirical Observation ◽  
Surface Fires ◽  
Independent Variable

Published data on two sets of experimental fires in jack pine (Pinusbanksiana Lamb.) forest were subjected to two forms of analysis. The first was a classification into surface fires and two kinds of crown fire, passive and active. In the second, the data were used to develop a model to predict both the spread rate of fire and the degree of crown consumption. The model consists mainly of two limiting equations for spread rate, one for surface fires and the other for full crowning fires; the independent variable is the Canadian Initial Spread Index. A critical surface intensity is first used to distinguish surface fires from crowning fires. A further process then estimates the degree of crowning and places the calculated final spread rate somewhere in the space between the limiting equations. The model inputs include six physical stand properties plus a pre-estimate of surface fuel consumption. It is a blend of physical theory and empirical observation.

Flame characteristics of wind-driven surface fires

1986 ◽  
Vol 16 (6) ◽  
pp. 1293-1300 ◽  
Author(s):  
Ralph M. Nelson Jr. ◽  
Carl W. Adkins
Keyword(s):  
Boundary Layer ◽  
Tilt Angle ◽  
Fire Behavior ◽  
Flame Length ◽  
Fire Intensity ◽  
Square Root ◽  
Pine Needle ◽  
Weather Variables ◽  
Practical Applications ◽  
Surface Fires

Twenty-two fires in a laboratory wind tunnel and 8 field fires were studied with video techniques to determine relationships between their flame characteristics and fire behavior. The laboratory fires were in pine needle fuel beds with and without an overlying stratum of live vegetation. These fuels simulated 2-year roughs in southeastern fuel types. The field bums were in 1- and 2-year roughs in similar fuels. Byram's fire intensity ranged from 98 to 590 kW/m in the laboratory, and from 355 to 2755 kW/m in the field. Flame lengths were proportional to the square root of fire intensity when fuel consumption exceeded 0.5 kg/m2, in agreement with predictions from buoyant flame theory. However, for burns in the needle layer (consumption approximately 0.5 kg/m2), flame lengths were constant at about 0.5 m, regardless of intensity. Similar values were observed on two of the field fires. It is speculated that flame length is limited by a boundary layer pattern for the overall flow, even though the flames themselves did not exhibit boundary layer characteristics. Also, laboratory correlations of flame tilt angle and fire intensity with other fire and weather variables depart from buoyant flame theory. Further study under field conditions is needed before relationships involving flame tilt angle, fire intensity, and wind speed should be used in practical applications.

scholarly journals Precise temperature calibration for laser heat treatment

2014 ◽  
Vol 3 (1) ◽  
pp. 47-54 ◽  
Author(s):  
M. Seifert ◽  
K. Anhalt ◽  
C. Baltruschat ◽  
S. Bonss ◽  
B. Brenner
Keyword(s):  
Heat Treatment ◽  
Fixed Point ◽  
Calibration Method ◽  
Processing Parameters ◽  
Industrial Processes ◽  
Laser Heat Treatment ◽  
Process Data ◽  
Treatment Processes ◽  
Laser Heat ◽  
Measurement Devices

Abstract. A new induction-heated fixed-point device was developed for calibration of temperature measurement devices typically used in laser heat treatment for the temperature range 1000–1500 °C. To define the requirements for the calibration method, selected measurement setups were compared as well as process data and results of industrial processes were analyzed. Computer simulation with finite element method (FEM) and finite difference method (FDM) was used to optimize the system components and processing parameters of the induction heating of fixed-point cells. The prototype of the fixed-point device was tested successfully, and the first measuring results are presented here. The new calibration method is expected to improve the quality and reproducibility of industrial heat treatment processes with temperature control.

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