scholarly journals The Roseville Bomb Disaster Simulated Train Braking System Tests and Boxcar Wood Floor Ignition Experiments

1991 ◽  
Vol 113 (1) ◽  
pp. 91-99
Author(s):  
B. Ross ◽  
P. G. Parikh
Keyword(s):  
Heat Flux ◽  
Cast Iron ◽  
Ignition Time ◽  
Thermal Response ◽  
Radiant Heat ◽  
Full Scale ◽  
Test Facility ◽  
Shield Effectiveness ◽  
Wood Floor ◽  
Wood Surfaces

A massive chain of property damaging explosions involving an ammunition train occurred at the railroad yard, Roseville, California. The train had pulled into the yard after a night trip of some 100 miles across Donner Summit and down the extended Norden-Roseville grade. Physical evidence confirmed that first explosions were centered at a DODX type boxcar loaded with 250 lb. bombs. Further, bomb cook-off detonation tests established that the triggering bomb blast was not a result of shock loads but rather derived from an engulfing fire initiated in the boxcar wood plank floor under influence of extended heavy braking action on the mountain grade. It was also suspected that high friction composition brake shoes were fitted on the car as replacements for cast iron shoes but the brake mechanical linkage lever ratios had not been modified as required. Results of a comprehensive research program are presented within context of the explosion event, and include analytical computer simulation of train descent profiles on mountain grades through full scale dynamometer tests with actual rail wheels and ultimately more scientific scaled wood floor ignition experiments in the laboratory. The thermal response of a simulated DODX boxcar wood floor was studied through experiments, full scale at a rail wheel dynamometer test facility, and in the laboratory. Certain input data for the wood floor ignition test program were measured on an actual boxcar joined with a freight train consist in transit down the Norden-Roseville grade. Two series of scaled wood ignition experiments were conducted on simulated DODX boxcar floors. Objectives of these tests were to determine: Influence of a cooling air stream on the ignition behavior of radiantly heated wood surfaces, and effectiveness of DODX (stand-off) and AAR (flush) type spark shields in preventing ignition of wood surfaces under radiant heating. It was found that for radiant heat flux levels representative of high friction composition shoes under severe train braking conditions, low speed airflow (wind) exerts a dramatic influence on the wood ignition time. For example, average ignition time for a simulated boxcar floor at a heat flux level of 0.4 cal/cm2sec was determined to be 15.6 min. with a 5 mph wind as compared to 3.6 min. with no wind. In the spark shield effectiveness tests, conducted at heat flux levels representative of cast iron shoes under severe braking conditions, the DODX (stand-off) type spark shield failed to prevent spontaneous flaming ignition of a wood surface directly above it. Under identical conditions, no flaming ignition was encountered with the AAR (flush) type spark shield.

The OSU Heat Release Unit as a Screening Tool for California TB 133

1992 ◽  
Vol 10 (3) ◽  
pp. 243-259 ◽  
Author(s):  
James A. Gallagher ◽  
Theodore M. Smiecinski ◽  
Oscar M. Grace
Keyword(s):  
Heat Flux ◽  
Weight Loss ◽  
Heat Release ◽  
Radiant Heat ◽  
Full Scale ◽  
Performance Standard ◽  
Fabric Composites ◽  
Percentage Weight ◽  
Oxygen Consumption Calorimetry ◽  
Test Frame

The California TB 133 (TB 133) full-scale burn test was adopted by Illinois and Minnesota in 1990 as a performance standard for furniture to be used in places of public occupancy. TB 133 will become effective in California on January 1,1992 and is under consideration in Ohio and several other states. Since full-scale burn tests are expensive, we embarked on a program to deter mine if the OSU Heat Release Unit could be used as a screening test for TB 133. The percentage weight loss of foam/fabric composites after ten minutes in the OSU Unit at a radiant heat flux of 1.0 Watt/cm2 appears to be a good predictor of TB 133 performance. A series of 39 upholstery fabric/melamine-modified polyurethane foam composites were tested in BASF Corporation's Wyandotte, Michigan TB 133 burn facility and in our OSU Heat Release Unit. We found: · 11 of 12 samples which clearly failed the Cal TB 133 test lost over 40% of their weight at a heat flux of 1.0 Watt/cm2 in the OSU test. · 22 of 23 samples which clearly passed the Cal TB 133 test lost less than 40% of their weight at 1.0 Watt/cm2. · Four samples marginally passed the Cal TB 133 test and their weight loss values could not be correlated. The TB 133 criteria adopted in mid 1990 was used for this series of tests rather than the newer criteria using oxygen consumption calorimetry. All of the TB 133 failures in this study were due to weight loss using fabric-covered foam cushions on a metal test frame. No side arms were used. Work is continu ing to determine whether this correlation can be extended to other foam/fabric combinations.

Analytical Modeling of Solid Material Ignition Under a Radiant Heat Flux Coming From a Spreading Fire Front

2014 ◽  
Vol 6 (4) ◽  
Author(s):  
A. Lamorlette
Keyword(s):  
Heat Flux ◽  
Ignition Time ◽  
Thermal Inertia ◽  
Solid Material ◽  
Radiant Heat ◽  
Heat Fluxes ◽  
Polynomial Coefficients ◽  
Rate Of Spread ◽  
Fire Front ◽  
Ignition Times

This study aims at characterizing ignition of solid targets exposed to spreading fire fronts. In order to model radiant heat fluxes on targets in a realistic way, polynomial heat fluxes are chosen. Analytical solutions for the solid surface temperature evolution regarding different time-varying heat fluxes are discussed for high thermal inertia solids using a mathematical formalism, which allows for the methodology to be extended to the case of low thermal inertia. This formulation also allows calculation of ignition times for more realistic time-dependent fluxes than previous studies on the topic, providing a more general solution to the problem of solid material ignition. Polynomial coefficients are then obtained fitting heat flux coming from absorbing–emitting flames. A characterization of solid material ignition times regarding fire front rate of spread (ROS) is finally performed, showing the need to accurately model heat flux variations in ignition time calculations.

scholarly journals Experimental Study of Oriented Strand Board Ignition by Radiant Heat Fluxes

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 709
Author(s):  
Ivana Tureková ◽  
Iveta Marková ◽  
Martina Ivanovičová ◽  
Jozef Harangózo
Keyword(s):  
Heat Flux ◽  
Critical Heat Flux ◽  
Elevated Temperatures ◽  
Oriented Strand Board ◽  
Ignition Time ◽  
Radiant Heat ◽  
Heat Fluxes ◽  
Composite Panel ◽  
Substantial Part ◽  
Ignition Times

Wood and composite panel materials represent a substantial part of the fuel in many building fires. The ability of materials to ignite when heated at elevated temperatures depends on many factors, such as the thermal properties of materials, the ignition temperature, critical heat flux and the environment. Oriented strand board (OSB) without any surface treatment in thicknesses of 12, 15 and 18 mm were used as experimental samples. The samples were gradually exposed to a heat flux of 43 to 50 kW.m−2, with an increase of 1 kW.m−2. At heat fluxes of 49 kW.m−2 and 50 kW.m−2, the ignition times are similar in all OSB thicknesses, in contrast to the ignition times at lower heat fluxes. The influence of the selected factors (thickness and distance from the heat source) was analysed based on the experimentally obtained data of ignition time and weight loss. The experimentally determined value of the heat flux density was 43 kW.m−2, which represented the critical heat flux. The results show a statistically significant effect of OSB thickness on ignition time.

Thermal response of plasma sprayed tungsten coating to high heat flux

2004 ◽  
Vol 70 (4) ◽  
pp. 341-349 ◽  
Author(s):  
X. Liu ◽  
L. Yang ◽  
S. Tamura ◽  
K. Tokunaga ◽  
N. Yoshida ◽  
...  
Keyword(s):  
Heat Flux ◽  
Thermal Response ◽  
High Heat ◽  
High Heat Flux ◽  
Tungsten Coating ◽  
Plasma Sprayed

Preliminary Evaluation of the 24 Ft. Diameter Fan Performance In the MinWaterCSP Large Cooling Systems Test Facility

2021 ◽  
Author(s):  
S. J. van der Spuy ◽  
D. N. J. Els ◽  
L. Tieghi ◽  
G. Delibra ◽  
A. Corsini ◽  
...  
Keyword(s):  
Scaling Laws ◽  
Static Pressure ◽  
Cooling System ◽  
Pressure Rise ◽  
Full Scale ◽  
Test Facility ◽  
Small Scale ◽  
Preliminary Evaluation ◽  
Cfd Analysis ◽  
Setting Angle

Abstract The MinWaterCSP project was defined with the aim of reducing the cooling system water consumption and auxiliary power consumption of concentrating solar power (CSP) plants. A full-scale, 24 ft (7.315 m) diameter model of the M-fan was subsequently installed in the Min WaterCSP cooling system test facility, located at Stellenbosch University. The test facility was equipped with an in-line torque arm and speed transducer to measure the power transferred to the fan rotor, as well as a set of rotating vane anemometers upstream of the fan rotor to measure the air volume flow rate passing through the fan. The measured results were compared to those obtained on the 1.542 m diameter ISO 5801 test facility using the fan scaling laws. The comparison showed that the fan power values correlated within +/− 7% to those of the small-scale fan, but at a 1° higher blade setting angle for the full-scale fan. To correlate the expected fan static pressure rise, a CFD analysis of the 24 ft (7.315 m) diameter fan installation was performed. The predicted fan static pressure rise values from the CFD analysis were compared to those measured on the 1.542 m ISO test facility, for the same fan. The simulation made use of an actuator disc model to represent the effect of the fan. The results showed that the predicted results for fan static pressure rise of the installed 24 ft (7.315 m) diameter fan correlated closely (smaller than 1% difference) to those of the 1.542 m diameter fan at its design flowrate but, once again, at approximately 1° higher blade setting angle.

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