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Improved Assessment of Fire Spread over Horizontal Cable Trays Supported by Video Fire Analysis

  • Pascal Zavaleta
  • Romain Hanouzet
  • Tarek Beji
Article
  • 13 Downloads

Abstract

Fire safety analyses in nuclear power plants need to assess the heat release rate (HRR) of potential cable fires. This study deals with the FLASH-CAT model which assesses the HRR of a fire spreading over horizontal ladder cable trays. As part of the OECD PRISME-2 project, fire tests which involved horizontal trays supported by a wall, highlighted fast fire growth and large HRR peak. This study investigated the ability of the FLASH-CAT model to predict the HRR for such configuration. The first assessments of the PRISME-2 tests with the FLASH-CAT model significantly delayed the ignition and under-estimated the fire growth rate and the HRR peak. A video fire analysis method was developed and contributed to propose updated input parameters, such as the ignition time and the horizontal spread rate, for cable tray configurations with a wall. In addition, modifications in the model which affect the burning cable tray area and the local fire duration are also discussed. The assessments of the PRISME-2 experiments with the modified FLASH-CAT model and the proposed input parameters are consistent with the measured HRR. In addition, the modified model also gives acceptable predictions of the HRR for numerous tests of the CHRISTIFIRE programme.

Keywords

CHRISTIFIRE Fire spread FLASH-CAT Heat release rate Horizontal cable trays PRISME-2 Video fire analysis 

List of symbols

\( A\left( t \right) \)

Burning cable tray area (m2)

ATH

Alumina trihydrate

CHF

Critical heat flux for ignition (kW·m−2)

Cp

Specific heat (kJ·kg−1·K−1)

d

Cable diameter (m)

e

Spacing between the cable trays (m)

EVA

Ethylene–vinyl acetate

HFFR

Halogen-free flame retardant

HRR

Heat release rate (kW)

HRRPUA

Heat release rate per unit area (kW·m−2)

K

Thermal conductivity (kW·m−1·K−1)

\( L_{b,i} \left( t \right) \)

Burning length of a cable tray i (m)

Li

Length of a cable tray i (m)

L0

Length of the gas burner (m)

\( m^{\prime} \)

Linear mass density (kg·m−1)

MC′′

Combustible mass per unit area (kg·m−2)

n

Number of cables per tray (–)

Ntrays

Number of cable trays (–)

\( \dot{q}_{f}^{{\prime \prime }} \)

Heat flux from flames to the cable surface (kW·m−2)

\( \dot{Q}\left( t \right) \)

HRR of horizontal ladder cable tray fire (kW)

\( \dot{Q}_{burner} \left( t \right) \)

Fire power of the ignition source (kW)

\( \dot{q}_{avg}^{{\prime \prime }} \)

Average heat release rate per unit area of cable tray (kW·m−2)

PE

Polyethylene

PVC

Poly(vinyl chloride)

VFA

Video fire analysis

VH, i

Horizontal spread velocity or horizontal spread rate along a cable tray i (m·s−1)

Tig, i

Ignition time of a cable tray i for vertical spread (s)

Tig

Ignition temperature of the cables (°C)

To

Initial temperature of the cables (°C)

W

Tray width (m)

\( x_{e,i} \left( t \right) \)

Location of the extinction front along a cable tray i (mm)

\( x_{f,i} \left( t \right) \)

Location of the flame front along a cable tray i (mm)

Yp

Mass fraction of plastic material (–)

Greek characters

β

Angle formed by the initial V-shaped burning pattern or spread angle (°)

\( \delta \)

Thermal penetration depth (m)

\( \Delta H_{c,eff} \)

Effective heat of combustion (MJ·kg−1)

\( \Delta t_{fire} \)

Fire duration at a given location of a tray or local fire duration (s)

\( \Delta t_{burner} \)

Fire duration of the gas burner (s)

\( \nu \)

Char yield (–)

\( \rho \)

Mass density (kg·m−3)

Notes

References

  1. 1.
    EPRI/NRC-RES (2005) Fire PRA Methodology for nuclear power facilities: vol 2: Detailed methodology. Electric Power Research Institute (EPRI), Palo Alto, CA, and U.S. Nuclear Regulatory Commission, Office of Nuclear Regulatory Research (RES), Rockville, MD: 2005, EPRI TR-1011989 and NUREG/CR-6850Google Scholar
  2. 2.
    Organisation for Economic Co-operation and Development (OECD) Nuclear Energy Agency (NEA), Committee on the Safety of Nuclear Installations (CSNI): OECD FIRE Database, Version: OECD FIRE DB 2014:2, Paris, France, proprietary, for members onlyGoogle Scholar
  3. 3.
    U.S. NRC and EPRI (2007) Verification and validation of selected fire models for nuclear power plant applications, NUREG-1824, U.S. Nuclear Regulatory Commission, Washington, DCGoogle Scholar
  4. 4.
    Iqbal N, Salley M H, (2004) Fire dynamics tools (FDTs): quantitative fire hazard analysis methods for the U.S. Nuclear regulatory commission fire protection inspection program, Final report, NUREG-1805, U.S. Nuclear Regulatory Commission, Washington, DCGoogle Scholar
  5. 5.
    Stoliarov SI, Crowley S, Lyon RE, Linteris GT (2009) Prediction of the burning rates of non-charring polymers. Combust Flame 156(5):1068–1083CrossRefGoogle Scholar
  6. 6.
    Lautenberger C, Fernandez-Pello C (2009) Generalized pyrolysis model for combustible solids, Fire Saf J 44:819–839CrossRefGoogle Scholar
  7. 7.
    Matala A, Lautenberger C, Hostikka S (2012) Generalized direct method for pyrolysis kinetic parameter estimation and comparison to existing methods. J of Fire Sci 30(4):339–356CrossRefGoogle Scholar
  8. 8.
    Mc Grattan KB, Hostikka S, Floyd JE, Baum HR, Rehm RG, Mell WE, Mc Dermott R (2009) FDS technical reference guide. vol 1: Mathematical model. Technical report, NIST, FDS Version 5.4Google Scholar
  9. 9.
    Boyer G (2017) Fully coupled CFD simulation of the pyrolysis of non-charring polymers: a predictive approach, Fire Saf J 91:208–217CrossRefGoogle Scholar
  10. 10.
    Lee BT (1985) Heat release rate characteristics of some combustible fuel sources in nuclear power plants, NSBSIR 85-3195, National Bureau of Standards, Washington, DCGoogle Scholar
  11. 11.
    Babrauskas V (2002) Heat release rates, SFPE handbook of fire protection engineering, 3rd edn, Section 3, Chapter 1, pp 3–16Google Scholar
  12. 12.
    U.S. NRC and EPRI (2004) Fire PRA methodology for nuclear power facilities, NUREG/CR-6850, U.S. Nuclear Regulatory Commission, Washington, DCGoogle Scholar
  13. 13.
    McGrattan K, Lock A, Marsh N, Nyden M, Bareham S, Price M, Morgan AB, Galaska M, Schenck K, Stroup D (2012), Cable heat release, ignition, and spread in tray installations during fire (CHRISTIFIRE). Phase 1: Horizontal Trays, NUREG/CR-7010, U.S.NRCGoogle Scholar
  14. 14.
    McGrattan K, Bereham S (2013) cable heat release, ignition, and spread in tray installations during fire (CHRISTIFIRE). Phase 2: Vertical Shafts and Corridors, NUREG/CR-7010, Vol. 2, U.S.NRCGoogle Scholar
  15. 15.
    Audouin L, Prétrel H, Zavaleta P, OECD PRISME 2 Fire Research Project (2011–2016), 2013, Current status and perspectives. In: 13th international post-conference seminar on fire safety in nuclear power plants and installations, Columbia, USAGoogle Scholar
  16. 16.
    Zavaleta P, Charbaut S, Basso G, Audouin L (2013) Multiple horizontal cable tray fire in open atmosphere. In: Thirteenth international conference of the fire and materials, pp 57–68. San Francisco, USAGoogle Scholar
  17. 17.
    Investigation heat and smoke propagation mechanisms in multi-compartment fire scenarios. Final report of the PRISME project, NEA/CSNI/R(2017) 14, January 2018Google Scholar
  18. 18.
    Meinier R, Sonnier R, Zavaleta P, Suard S, Ferry L (2018) Fire behavior of halogen-free flame retardant electrical cables with the cone calorimeter. J Hazard Mater 342:306–316.  https://doi.org/10.1016/j.jhazmat.2017.08.027 CrossRefGoogle Scholar
  19. 19.
    Hanouzet R (2015) Characterization of fire spreading over an installation of multiple cable trays, IRSN technical report, PSN-RES/SA2I-2015-310, October 2015Google Scholar
  20. 20.
    Tewarson A, Khan M (1992) A new standard test method for the quantification of fire propagation behavior of electrical cables using factory mutual research corporation‘s small-scale flammability apparatus, fire technology 28:215–227CrossRefGoogle Scholar
  21. 21.
    Quintiere JG, Surface flame spread, SFPE handbook of fire protection engineering, 3rd edn, Section two, Chapter 12. ISBN:087765-451-4Google Scholar
  22. 22.
    Mowrer F, Williamson R, Flame spread evaluation for thin interior finish materials fire safety science. In: Proceedings of the third international symposium, pp 237–247Google Scholar
  23. 23.
    Sumitra PS (1982) Categorization of cable flammability. Intermediate-scale fire tests of cable tray installations. Interim report NP-1881, research project 1165-1, Factory Mutual Research Corporation, Norwood, MAGoogle Scholar
  24. 24.
    Beyler, C., L. and Hirschler, M., M. (2002) Thermal Decomposition of Polymers, SFPE handbook of Fire Protection Engineering, 3rd edn, Section 1, Chapter 7. ISBN:087765-451-4Google Scholar
  25. 25.
    Zavaleta P, Audouin L (2018) Cable tray fire tests in a confined and mechanically ventilated facility. Fire Mater 42:28–43.  https://doi.org/10.1002/fam.2454 CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSN-RES, SA2ISt Paul-Lez-Durance CedexFrance
  2. 2.Department of Flow, Heat and Combustion MechanicsGhent University-UgentGhentBelgium

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