NUREG/CR-4679 SAND86-0311 RP Printed February 1987 Quantitative Data on the Fire Behavior of Combustible Materials Found in Nuclear Power Plantt: A Literature Review S. P. Nowlen Prepared by " Sandia N ational Laboratories . .e C alif Albuquerque. New Mexico 87185 and Livermore, Catifomia 94550 for the United States Department of Energy under Contract DE-AC04-76DP00789 Prepared for U. S. NUCLEAR REGULATORY COMMISSION SF2900Q(8-81) NUREG/CR-4679 SAND86-0311 RP QUANTITATIVE DATA ON THE FIRE BEHAVIOR OF COMBUSTIBLE MATERIALS FOUND IN NUCLEAR POWER PLANTS: A LITERATURE REVIEW S. P. Nowlen February 1987 Sandia National Laboratory Albuquerque. New Mexico 87185 operated by Sandia Corporation for the U. S. Department of Energy Prepared for Electrical Engineering Branch Division of Engineering Technology Office of Nuclear Regulatory Research U. S. Nuclear Regulatory Commission Washington. D.C. 20555 Under Memorandum of Understanding DOE 40-550-75 NRC FIN A1010 ABSTRACT This report presents the findings of a task in which cur- rently available fire research literature was reviewed for quantitative data on the burning characteristics of combus- tible materials that are found in nuclear power plants. The materials considered for which quantitative data were available include cable insulation materials, flammable liquids, furniture, trash and general refuse, and wood and wood products. A total of 90 figures and tables, taken pri- marily from the referenced works, which summarize the available quantitative fire characterization information for these materials is presented. Eighty-two references are cited. Many more papers were con- sidered though it was found that much of the data presented on fire behavior of materials is of a qualitative nature. This data often results from qualitative pass-fail or rela- tive ranking tests. Information of a qualitative nature was not considered for presentation in this review. Fire characteristics emphasized include mass release, heat release, distribution of heat released into radiative and convective fractions, combustion products generation rates. flame heights, ignitability. flame spread rate, and feedback effects. The toxicity of combustion products was not con- sidered in this study.. It is identified in the review that fire characterization information for nuclear power plant type fuels is needed primarily for use in risk assessment analyses. Much of the data presented here may be used as stand-alone results for use as input to environmental simulation computer codes. This generally requires direct knowledge of the actual heat release rate-of a given fire. Data of this type are pre- sented for most fuel types including cable insulation in a cable tray configuration, liquid fuels, and trash fires. Other applications in risk assessment require the use of computer simulation models that not only predict the envi- ronmental effects of a given fire but also attempt to predict the growth and development history of a fire in a particular fuel configuration. This requires more general- ized information on the physical properties of the fuel element. These properties include the common physical properties such as density, thermal conductivity, and specific heat, as well as other properties more directly related to fire behavior including ignition criteria, sensitivity of mass loss to fire feedback, flame spread properties, and heat release per unit mass. Data of this type, particularly for cable insulation materials, are presented. These data were typically obtained from small-scale tests and the limitations of these small-scale test results are discussed. -iii/iv- CONTENTS Page ABSTRACT ................... ....................... iii EXECUTIVE SUMMARY ................ .................. 1 1. INTRODUCTION .................. ................... 4 1.1 Scope of the Current Work ...... ... .......... 4 1.2 The Fuel Sources of Concern ........ ......... 5 1.3 General Trends in Past and Present Fire Research .................... ............... 7 1.4 Other Complementary Works ........ .......... 10 2. THE AVAILABLE DATA ON THE BURNING OF CABLE INSULATION .............. .................... 13 2.1 Small-Scale Testing of Cable Insulation Materials ...... .................. ...... 13 2.1.1 The OSU Rate of Heat Release Apparatus ......... .............. 13 2.1.2 The FMRC Small-Scale Flammability Apparatus ......... .............. 14 2.1.3 Small-Scale Cable Testing at LLNL . 16 2.1.4 Other Small-Scale Testing Efforts . 19 2.2 Large-scale Cable and Cabinet Fire Tests . 20 2.2.1 Testing by Sandia National Laboratory ........ .............. 20 2.2.2 Testing by Lawrence Livermore National Laboratory ........ .............. 22 2.2.3 Testing by Factory Mutual Research Corporation ....... ............. 25 2.2.4 Testing by Bell Laboratory ...... .. 30 2.2.5 Testing by Lawrence Berkeley Laboratory ........ .............. 31 3. CHARACTERIZATION OF FURNITURE FIRES .. ....... 33 4. CHARACTERIZATION OF LIQUID FUEL FIRES . ..... 34 4.1 Introduction ....... .... ................ .... 34 4.2 Estimating Pool Fire Burning Rates ..... 34 4.3 Ignitability of High-Fire point Liquid Fuels . .................................... 36 4.4 Characterization of Hydraulic Fluid Spray Fires .............. .................... 38 5. CHARACTERIZATION OF WOOD AND WOOD PRODUCT FIRES . 339 CONTENTS (Continued) Page 6. CHARACTERIZATION OF TRASH AND GENERAL REFUSE FIRES ................. ...................... 40 6.1 Introduction ............................... 40 6.2 Trash Fire Testing by LBL ... .......... 40 6.3 Trash Fire Testing by SNL ... .......... 41 6.4 Predictive Correlations for Trash Fires . 41 7. CONCLUSIONS ............... ................... 43 REFERENCES ................ ...................... 46 - vi - LIST OF FIGURES Figure Page I Histogram showing amounts of oil typically reported as transient combustible fuels in NPP inspection reports (Reference 3] . 53 2 Histogram showing amounts of solvent typically reported as transient combustible fuels in NPP inspection reports [Reference 3] .............. ................ 54 3 Histogram showing typical amounts of paint reported as transient combustible fuels in NPP inspection reports [Reference 3] . 55 4 Histogram showing typical amounts of paper and/or trash reported as transient combustible fuels in NPP inspection reports (Reference 3] ..................... 56 5 Comparison of heat release rate values obtained for PMMA samples from a modified OSU Rate of Heat Release Apparatus using oxygen consumption and conventional calorimetry methods [Reference 24] ..... 57 6 Comparison of heat release rate data for PMMA samples from a modified OSU apparatus and the NBS-II apparatus at a nominal heat flux of 25 kW/m 2 based on oxygen consumption [Reference 24] .. ......... .. 58 7 Mass burning rate per unit exposed surface area versus net external heat flux for various polymers [Reference 30] ..... 59 a Mass burning rate per unit exposed surface area versus net external heat flux for various organic fluids [Reference 30] . 60 9 Correlation between yield of CO2 and actual heat of combustion for cable samples [Reference 31] ... ........... .. 67 10 Correlation between actual heat of combustion and percentage of cable weight attributed to insulation [Reference 31] . 67 -vii- LIST OF FIGURES (Continued) Figure Page 11 Correlation between yield of unburned hydrocarbons and percent of cable weight attributed to insulation (Reference 31] 68 12 Correlation between yield of carbon monoxide and percent of cable weight attributed to insulation [Reference 31] *. 68 13 Time to ignition of cable samples [Reference 43] . 74 14 Rate of flame spread versus exposure heat flux for LLNL small-scale radiant exposure tests [Reference 44] ........ 80 I5 Influence of oxygen concentration on surface mass loss flux and surface temperature for nonflaming PMMA and PE [Reference 45] . 81 16 Effect of wire diameter and wire orientation on flame propagation rate for PMMA and PE threads [Reference 46] * . 82 17 Estimated heat release rates for heptane pool experiments and heptane pool - cable tray tests from SNL/UL fire tests [Reference 49] . 83 18 Burn mode analysis threshold diagrams with example data from actual fire tests included; time increases clockwise around plotted data [Reference 54] ... ........ * . 84 19 Experimental apparatus used in LLNL vertical cable fire tests [Reference 54] 20 End view of cable installations illustrating packing densities; note that slats are used to separate layers but no cable trays as such are used [Reference 43] . 85 21 Comparison of mass loss-based and oxygen consumption-based heat release rates for LLNL Tests (a) VCAB-2 (Hypalon) and (b) VCAB-5 (PVC) [Reference 43]...... •. 88 -viii- LIST OF FIGURES (Continued) Figure Page 22 Three-dimensional view of test enclosure used for FMRC/EPRI cable tray fire tests (References 56. 57] .......... ........... * 90 23 Cable tray arrangement used in Test 3 of second series of FMRC/EPRI cable tray fire tests [Reference 57] . ........ 91 24 Estimated actual heat release rate versus time for FMRC/EPRI Tests 2 and 3 of the second series (Reference 57] . .... .. 92 25 Mass release rate versus area of involvement for first series of FMRC/EPRI PE/PVC extinguishment fire tests [Reference 21] ......... ............... 93 26 Area of involvement versus time for first series of FMRC/EPRI extinguishment fire tests [Reference 21] ..................... 94 27 Mass flux versus exposure heat flux for PE/PVC cable #5 based on data of Tewarson [31] and Lee [32] ............