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Hansen, R. (2015). Analysis of methodologies for calculating the heat release rates of mining vehicle fires in underground mines. Fire Safety Journal, 71, 194-216
Open this publication in new window or tab >>Analysis of methodologies for calculating the heat release rates of mining vehicle fires in underground mines
2015 (English)In: Fire Safety Journal, ISSN 0379-7112, Vol. 71, p. 194-216Article in journal (Refereed) Published
Abstract [en]

Four different methodologies for calculating the ignition of different components on a mining vehicle in a mine drift were analysed. The results were compared with two full-scale fire experiments on mining vehicles. The four different methods are based on physical relations for fire spread between combustible components of the mining vehicles. The first two methods use a critical heat flux as ignition criterion while the other two methods use an ignition temperature. A sensitivity analysis was performed and the most influencing parameter of the methods was further analyzed. The calculated results were compared with the measured results from the experiments. The two methodologies applying an ignition temperature criterion were ruled out at as the surface temperatures of all fuel components never achieved the corresponding ignition temperatures. For the two methods applying a critical heat flux criterion it was found that the expression not including a flame radiation term was not suitable as it was found that the flame radiation played an important part with respect to spread mechanisms. The expression containing a flame radiation term was found to come very close to the observed ignition times, except in the case of the left, rear tyre of the drilling rig where it predicted a much higher ignition time than the one observed. The difference is unclear and would have to be investigated further. It was also found that the surface heat losses had none effect on the output results and could therefore be neglected in the calculations. In the case of the wheel loader the calculated heat release rate curves did not match the measured curve as well as in the case of the drilling rig. The difficulty in this case consists of accurately predicting the mechanical failure of a component - in this case a suction hose - that would initiate the very significant hydraulic oil pool fire.

Keywords
Fire spread, Heat flux, Heat release rate, Ignition, Ignition temperature, Mine drift, Mining vehicle, Atmospheric temperature, Construction equipment, Drilling rigs, Experiments, Failure (mechanical), Fires, Sensitivity analysis, Vehicles, Heat Release Rate (HRR), Ignition criterion, Ignition temperatures, Influencing parameters, Mechanical failures, Mining vehicles, Surface temperatures, Underground mine transportation
National Category
Other Engineering and Technologies
Identifiers
urn:nbn:se:mdh:diva-27222 (URN)10.1016/j.firesaf.2014.11.008 (DOI)000349728000018 ()2-s2.0-84918565578 (Scopus ID)
Available from: 2014-12-29 Created: 2014-12-29 Last updated: 2016-05-13Bibliographically approved
Hansen, R. (2015). Statistical expressions on water based wildfire suppression in Sweden, 1996-2011. International Journal of Safety and Security Engineering, 5(2), 124-141
Open this publication in new window or tab >>Statistical expressions on water based wildfire suppression in Sweden, 1996-2011
2015 (English)In: International Journal of Safety and Security Engineering, ISSN 2041-9031, E-ISSN 2041-904X, Vol. 5, no 2, p. 124-141Article in journal (Refereed) Published
Abstract [en]

Little research has been conducted with respect to water requirements for wildfire suppression. An exploratory and robust regression analysis was conducted on statistical material extracted from a Swedish database, focusing on data related to the fire suppression. The variables included are the amount of water applied, application rate of water, extinguishing time, flame height, and the total fire area. The results of the analysis with potential relationships are described, discussed, and compared with results from earlier research. After initial outlier detection, a robust regression analysis was performed and relationships developed. It was found that the developed relationships could predict the dependent variable very well; this was especially the case with the extinguishing time as a function of the total fire area. The relationship with the lowest ability to predict the dependent variable was the application rate of water as a function of the total fire area. The large number of parameters and their included uncertainties could be an explanation to the increased inability to predict the dependent variable. When comparing the control times of earlier conducted building fire studies with the extinguishing times of developed relationships, it was found that the control times were much longer than the corresponding extinguishing times. The reason behind was most likely due to the difference in the fire area applied in the equations. The resulting relationships for the grass fuel type were found to have lower ability to predict the dependent variable. The reason behind this is unclear and needs to be investigated further.

Place, publisher, year, edition, pages
WITPress, 2015
Keywords
Extinguishing time, Robust regression analysis, Water application, Wildfire suppression, Data mining, Forecasting, Regression analysis, Application rates, Dependent variables, Fire suppression, Outlier Detection, Statistical expression, Water requirements, Fires
National Category
Other Engineering and Technologies
Identifiers
urn:nbn:se:mdh:diva-35216 (URN)10.2495/SAFE-V5-N2-124-141 (DOI)2-s2.0-85016817424 (Scopus ID)
Available from: 2017-04-20 Created: 2017-04-20 Last updated: 2017-04-20Bibliographically approved
Hansen, R. (2015). Study of heat release rates of mining vehicles in underground hard rock mines. (Doctoral dissertation). Västerås: Mälardalen University
Open this publication in new window or tab >>Study of heat release rates of mining vehicles in underground hard rock mines
2015 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

A unique study on fire safety in hard rock underground mines with focus on heat release rates of mining vehicles is presented. A literature inventory was conducted with respect to fires in underground hard rock mines, which revealed that the most common fire cause in underground mines was flammable liquid sprayed onto hot surface and the most common fire object was a vehicle. A major concern was the lack of documented fire experiments in mining vehicles and heat release rate curves. It also revealed the limited research carried out on fire safety and fire development on vehicles found in hard rock underground mines.

In order to fill the gap of knowledge lack on heat release rates, fire experiments were carried out on wood cribs and wooden pallets in a model-scale tunnel with longitudinal ventilation where the distance between the fuel items were kept constant as well as varied. Different ignition criteria were applied in the ensuing calculations. It was found that the critical heat flux criterion generally showed very good agreement with the corresponding results of performed fire experiments but tended to have too short ignition times when the distance between the fuel items was increased. The ignition temperature criterion generally performed poorly compared with the measured results, but it was found that the accuracy improved considerably as the distance between the fuel items and the amount of energy accumulated on the fuel surface was increased.

As a final approach, two full-scale fire experiments were carried out in an operative underground mine using a wheel loader and a drilling rig respectively. The resulting heat release rates of the experiments were compared with calculated overall heat release rates applying the different ignition criteria. It was found that the critical heat flux criterion resulted in ignition times very close to the observed ignition times. The ignition temperature criterion resulted in surface temperatures that never achieved the corresponding ignition temperatures. Some difficulties were experienced when calculating the heat release rate curve of the wheel loader, as it was difficult to accurately predict the mechanical failure of a significant part initiating the highly significant fire in the hydraulic oil. Additional heat terms were added to the heat balance, where the added flame radiation term was found to have a large impact on the output results while the heat loss terms were found to have very little effect.

Place, publisher, year, edition, pages
Västerås: Mälardalen University, 2015
Series
Mälardalen University Press Dissertations, ISSN 1651-4238 ; 178
National Category
Other Engineering and Technologies not elsewhere specified
Research subject
Energy- and Environmental Engineering
Identifiers
urn:nbn:se:mdh:diva-27776 (URN)978-91-7485-201-1 (ISBN)
Public defence
2015-05-27, Delta, Västerås, 13:15 (English)
Opponent
Supervisors
Available from: 2015-04-02 Created: 2015-03-31 Last updated: 2015-06-29Bibliographically approved
Hansen, R. & Ingason, H. (2013). Full-scale fire experiments with mining vehicles in an underground mine. Västerås
Open this publication in new window or tab >>Full-scale fire experiments with mining vehicles in an underground mine
2013 (English)Report (Other academic)
Abstract [en]

This report comprises two full scale fire experiments in a mine drift in Sala, Sweden,involving a loader and a drilling rig respectively.

It was found in the experiment involving the loader that the front part of the vehiclenever ignited. The maximum measured heat fluxes at the front tyres were found tonever exceed the critical heat flux of natural rubber and thus ignition never occurred.Furthermore, the maximum temperature recorded at the hydraulic hoses in the waistwas 381 K, thus the low temperatures did not allow for further fire spread. The maximumheat release rate from the experiment was 15.9 MW and it was attained approximately 11 minutes after ignition. The resulting heat release rate curve of the wheel loaderfire displays a fire that is dominated by initially the sudden increase when primarily the first tyre is engulfed by flames and then by the slowly declining heat release ratesof the large tyres of the vehicle. Still, the stop of fire spread from the waist and forward clearly shortened the duration of the fire considerably.

It was found in the experiment with the drilling rig that the entire vehicle had participated in the fire and the combustible material had been consumed – except for the hydraulic hoses approximately two meters in front of the cab and forward, some amount of hydraulic oil and most of the low voltage cable on the cable reel. The maximum heatrelease rate from the experiment was 29.4 MW and it was attained after 21 minutes. The resulting heat release rate curve of the drilling rig displays a fire with high heat release rates and relatively short lived.

Place, publisher, year, edition, pages
Västerås: , 2013. p. 62
Series
Studies in Sustainable Technology / Forskningsrapport ; 2013:2
Keywords
Fires, full-scale fire experiments, mines, mining, vehicles, tunnels
National Category
Energy Engineering
Research subject
Energy- and Environmental Engineering
Identifiers
urn:nbn:se:mdh:diva-20912 (URN)978-91-7485-115-1 (ISBN)
Projects
BARBARA
Funder
Knowledge Foundation
Available from: 2013-08-15 Created: 2013-08-15 Last updated: 2015-11-16Bibliographically approved
Hansen, R. & Ingason, H. (2013). Heat release rate measurements of burning mining vehicles in an underground mine. Fire safety journal, 61, 12-25
Open this publication in new window or tab >>Heat release rate measurements of burning mining vehicles in an underground mine
2013 (English)In: Fire safety journal, ISSN 0379-7112, E-ISSN 1873-7226, Vol. 61, p. 12-25Article in journal (Refereed) Published
Abstract [en]

Heat release rates from two full-scale fire experiments with mining vehicles in an underground mine are presented. The mining vehicles involved were a wheel loader and a drilling rig typical for mining operations. The calculated peak heat release rate of the loader was 15.9 MW and occurred after approximately 11 min from ignition. The calculated peak heat release rate of the drilling rig was 29.4 MW and occurred after approximately 21 min from ignition. The heat release rate was calculated from measured data of gas concentrations of oxygen, carbon monoxide and carbon dioxide, measured gas velocity and measured gas temperatures. The fuel load of the wheel loader consisted mainly of the tyres, the hydraulic oil and the diesel fuel. The fuel load of the drilling rig consisted mainly of the hydraulic oil and the hydraulic hoses. The calculated heat release rate curves were controlled by comparing the summed up energy contents of the participating components with the integrated heat release rate curves. © 2013 Elsevier Ltd.

Keywords
Full-scale fire experiment, Heat release rate, Mining vehicle, Underground mine
National Category
Engineering and Technology Energy Engineering
Research subject
Energy- and Environmental Engineering
Identifiers
urn:nbn:se:mdh:diva-21441 (URN)10.1016/j.firesaf.2013.08.009 (DOI)000327365700002 ()2-s2.0-84883339568 (Scopus ID)
Available from: 2013-09-13 Created: 2013-09-13 Last updated: 2017-12-06Bibliographically approved
Hansen, R. (2013). Investigation on fire causes and fire behaviour: Vehicle fires in underground mines in Sweden 1988–2010.
Open this publication in new window or tab >>Investigation on fire causes and fire behaviour: Vehicle fires in underground mines in Sweden 1988–2010
2013 (English)Report (Other academic)
Abstract [en]

This report is part of the research project “Fire spread and heat release rate of underground mining and tunnelling vehicles – BARBARA”, conducted by a research group at MälardalenUniversity.

The project’s aim is to improve fire safety in mines and tunnels during construction in order to obtain a safer working environment for the people working for the mining companies as well as the tunnelling companies in Sweden or for visitors in mines open to the public.

This report deals with the second step in the project: the investigation regarding fire causes and fire behaviour of vehicle fires in underground mines based upon material from GRAMKO (the work environment committee of the mine and mineral industry in Sweden).

The main purposes of the investigation are:

  • To investigate and present fire causes, types of vehicles involved in fires, fire spread and fire behaviour of vehicle fires in underground mines.
  • To give recommendations on the continued work with the full-scale fire tests regarding the initial fire and its position.

The conclusions were that:

  • With respect to vehicle fires involving only the start object, a typical fire occurs in a loader or a drilling rig and is due to electrical fault – for example short-circuit of cables – in the engine compartment, resulting in a slow and limited fire spread.
  • Regarding vehicle fires limited to the start object and an adjacent object is that it usually occurs in a loader and is due to electrical causes, resulting in a slow and limited fire spread. Typically, electrical cables would play an important role when it comes to the fire spread to adjacent objects.
  • Vehicle fires involving the entire vehicle usually occur in a service vehicle or a loader and are typically caused by diesel being sprayed – for example due to a pipe/hose coming loose – on the engine, resulting in a rapid fire spread.
  • In future full-scale fire experiments involving a diesel loader and a drilling rig, the vehicles will have to be ignited using a diesel fire – for example a pool fire under­neath or inside the engine compartment – that is shielded and positioned close to larger amounts of combustibles – such as tires or hydraulic hoses – and continuously distributed fuels – such as electrical cables – in order to achieve a rapid fire growth and fire spread that eventually engulf the entire vehicle. 
Publisher
p. 28
Series
Studies in Sustainable Technology / Arbetsrapport ; 2013:3
Keywords
Vehicle fires, underground mines, fire causes, statistics
National Category
Energy Engineering
Research subject
Energy- and Environmental Engineering
Identifiers
urn:nbn:se:mdh:diva-21287 (URN)978-91-7485-119-9 (ISBN)
Projects
BARBARA
Funder
Knowledge Foundation
Available from: 2013-09-09 Created: 2013-09-09 Last updated: 2014-06-09Bibliographically approved
Hansen, R. (2012). Estimating the amount of water required to extinguish wildfires under different conditions and in various fuel types. International journal of wildland fire, 21(5), 525-536
Open this publication in new window or tab >>Estimating the amount of water required to extinguish wildfires under different conditions and in various fuel types
2012 (English)In: International journal of wildland fire, ISSN 1049-8001, E-ISSN 1448-5516, Vol. 21, no 5, p. 525-536Article in journal (Refereed) Published
Abstract [en]

In wildland fires where water is used as the primary extinguishing agent, one of the issues of wildfire suppression is estimating how much water is required to extinguish a certain section of the fire. In order to use easily distinguished and available indicators, the flame length and the area of the active combustion zone were chosen as suitable for the modelling of extinguishing requirements. Using Byram's and Thomas' equations, the heat release rate per unit length of fire front was calculated for low-intensity surface fires, fires with higher wind conditions, fires in steep terrain and high-intensity crown fires. Based on the heat release rate per unit length of fire front, the critical water flow rate was calculated for the various cases. Further, the required amount of water for a specific active combustion zone area was calculated for various fuel models. Finally, the results for low-intensity surface fires were validated against fire experiments. The calculated volumes of water can be used both during the preparatory planning for incidents as well as during firefighting operations.

Keywords
active combustion zone, critical water application rate, fire point theory, flame length, suppression
National Category
Natural Sciences Energy Engineering
Research subject
Energy- and Environmental Engineering
Identifiers
urn:nbn:se:mdh:diva-17793 (URN)10.1071/WF11022 (DOI)000307175200006 ()2-s2.0-84864925492 (Scopus ID)
Available from: 2013-01-15 Created: 2013-01-15 Last updated: 2017-12-06Bibliographically approved
Hansen, R. & Ingason, H. (2012). Heat Release Rates of Multiple Objects at Varying Distances. Fire safety journal, 52, 1-10
Open this publication in new window or tab >>Heat Release Rates of Multiple Objects at Varying Distances
2012 (English)In: Fire safety journal, ISSN 0379-7112, E-ISSN 1873-7226, Vol. 52, p. 1-10Article in journal (Refereed) Published
Abstract [en]

Simple theoretical calculations of the overall heat release rate (HRR) of multiple objects at both constant and varying distances have been carried out. The results were compared to both fire experiments in a longitudinal ventilated model tunnel (scale 1:15) using piles of wooden pallets placed at varying distance from each other and with model scale fire experiments (scale 1:4) conducted with a freight truck commodity without roof over the piles of wooden pallets. Two different methods are presented which are based on physical relations for fire spread between the piles of wooden pallets. The first method uses a critical heat flux as ignition criteria while the other method uses an ignition temperature. The method using the critical heat flux as ignition criteria shows very good agreement with the corresponding experimental results used. The method using the ignition temperature as ignition criteria did not agree well with the corresponding experimental results. The prerequisite that the burning objects should not necessarily have to be positioned at equal distance was fulfilled.

National Category
Other Engineering and Technologies
Research subject
Energy- and Environmental Engineering
Identifiers
urn:nbn:se:mdh:diva-11305 (URN)10.1016/j.firesaf.2012.03.007 (DOI)000307132800001 ()2-s2.0-84860509088 (Scopus ID)
Projects
GRUVAN
Available from: 2011-01-04 Created: 2011-01-04 Last updated: 2017-09-27Bibliographically approved
Hansen, R. (2012). Methodologies for calculating the overall heat release rateof a vehicle in an underground structure. In: Anders Lönnermark & Haukur Ingason (Ed.), Proceedings from the fifth international symposium on tunnel safety and security", New York, USA, March 14-16, 2012: . Paper presented at The fifth international symposium on tunnel safety and security", New York, USA, March 14-16, 2012.
Open this publication in new window or tab >>Methodologies for calculating the overall heat release rateof a vehicle in an underground structure
2012 (English)In: Proceedings from the fifth international symposium on tunnel safety and security", New York, USA, March 14-16, 2012 / [ed] Anders Lönnermark & Haukur Ingason, 2012Conference paper, Published paper (Refereed)
Abstract [en]

Most common type of object involved in fires in underground structures such as underground minesare vehicles [1-3]. A major concern is the lack of documented fire experiments in vehicles/mobileequipment, which is especially the case for working vehicles such as loaders, drilling rigs etc. Theresulting heat release rate (HRR) curves are essential knowledge when designing new tunnel or minesections and overlooking existing sections, thus there is a great need for HRR curves.This paper encompasses the measurement of the HRR for two full-scale fire experiments with vehiclesrepresentative for underground structures and the reconstruction of the measured HRR by investigatingwhat methodology that fits the measured values best. The main purpose of the methodologies is toprovide HRR curves without having to perform full-scale fire tests of the vehicles, which would be ofconsiderable value.

Keywords
Heat release rate, critical heat flux, vehicle fire, tunnel, underground structure
National Category
Engineering and Technology Energy Engineering
Research subject
Energy- and Environmental Engineering
Identifiers
urn:nbn:se:mdh:diva-23618 (URN)
Conference
The fifth international symposium on tunnel safety and security", New York, USA, March 14-16, 2012
Available from: 2013-12-16 Created: 2013-12-16 Last updated: 2015-04-02
Hansen, R. (2012). Regression analysis of wildfire suppression. In: Brebbia C.A. & Perona G. (Ed.), Proceedings from the third international conference on modelling, monitoring and management of forest fires", New Forest, United Kingdom, May 22-24, 2012: . Paper presented at The third international conference on modelling, monitoring and management of forest fires", New Forest, United Kingdom, May 22-24, 2012.
Open this publication in new window or tab >>Regression analysis of wildfire suppression
2012 (English)In: Proceedings from the third international conference on modelling, monitoring and management of forest fires", New Forest, United Kingdom, May 22-24, 2012 / [ed] Brebbia C.A. & Perona G., 2012Conference paper, Published paper (Refereed)
Abstract [en]

One of the most important aims of forest fire research is how to better controlforest fires. One way to attain this aim is to develop better decision tools forestimating how much water is required for extinguishing a fire with a specific setof conditions. There has in the past generally been little research conducted withrespect to water requirements when suppressing a wildfire. A number ofexperiments were conducted in the early ‘70s where a spray rig with a nozzlearrangement was used in order to apply water uniformly across a fuel bed. Twostudies regarding the required duration of water application related to fires inbuildings were conducted in the past. Both studies were based upon statisticaldata from fire brigades; the duration of water application was determined as afunction of the fire area. This paper encompasses an analysis of more than64,000 wildfires occurring in Sweden between 1996 and 2009. The valuescalculated from the obtained formulations with regression analysis were found tobe in good agreement in the following cases: The amount of water as a functionof the extinguishing time, the extinguishing time as a function of the fire area;and the fire area as a function of the flame height. It was observed that thederived equations from the analysis in the above cases could provide an accuratecomputation. These relationships could be of considerable use when developingdecision tools for wildfire suppression, optimizing the use of resources duringthe suppression activities.

Keywords
wildfire suppression, regression analysis, extinguishing time, water amount, fire area
National Category
Energy Engineering
Research subject
Energy- and Environmental Engineering
Identifiers
urn:nbn:se:mdh:diva-23620 (URN)
Conference
The third international conference on modelling, monitoring and management of forest fires", New Forest, United Kingdom, May 22-24, 2012
Available from: 2013-12-16 Created: 2013-12-16 Last updated: 2013-12-16
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-8326-2860

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