一份关于锥形量热仪的国外研究报告
DEVELOPMENT OF A TESTECH CONE CALORIMETER FOR THE MEASUREMENT OF IGNITION AND FIRE PROPERTIES OF MATERIALS
By Suqin Ma
B.Sc, China Petroleum University, 1982
A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIRMENTS FOR
THE DEGREE OF
Master of Science in Engineering
in the Department
of
Mechanical Engineering This thesis is accepted
Dean of Graduate Studies THE UNIVERSITY OF NEW BRUNSWICK
January, 1994 c Suqin Ma, 1994
Abstract
A TESTech cone calorimeter utilizing the oxygen consumption principle has been developed for use in fire testing and research. It can be used to determine the heat release rate, mass loss rate, effective heat of combustion, time to ignition and smoke production rate for a variety of materials. The heat release rate is determined by measuring the combustion products gas flow and the oxygen depletion. The effective heat of combustion is calculated from a concomitant measurement of specimen mass loss rate in combination with the heat release rate. The smoke production rate is obtained by light obscuration in the combustion product stream.
In this study, the TESTech cone calorimeter was developed and fabricated based upon a design originating with the Center for Fire Research at National Institute of Standards and Technology (NIST). The necessary control and data acquisition, data reduction and analysis software was also developed. The system has been calibrated and checked using a standard calibration specimen, black PMMA(polymethylmethacrylate). Three typical types of commercial products, medium-density fibreboard; extruded polystyrene foam and high-density polyethylene board have also been tested at different heat flux levels. Good reproducibility and repeatability were achieved with the instrument.
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Acknowledgments
I wish to express my deep gratitude to Dr. James E.S. Venart, my supervisor, for his continuous guidance, encouragement, and support throughout the different stages of this work.
Special thanks are due to Mr. Dennis Can for his contributions in the fabrication of the apparatus and his kindness and patience. Mr. Charles R. Dutcher assisted in the development of some of the electronic components, and in the provision of the basic computer program for data acquisition. Mr. Vincent Boardman and Bob London of Mechanical Engineering as well as Mr. Richard Heartz of Electrical Engineering are also thanked for their assistance.
Vytenis Babrauskas, of the Center for Fire Research, NIST provided technical information and assistance for this study.
I am deeply grateful for helpful discussions and suggestions from Dr. Jacob Vanderline of Physics department and Dr. Bai Zhou of Mechanical Engineering department relative to the optical systems used.
Polycast Inc. of U.S. provided free of charge the samples of black PMMA used for the calibration of the instrument. Financial support for this study from the Natural Science and Engineering Research Council is gratefully appreciated.
I would like finally to express my deep gratitude to my parents, and family for their support and encouragement during my studies.
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Table of Contents
Page
ABSTRACT ii
ACKNOWLEDGMENTS iii
TABLE OF CONTENTS iv
LIST OF FIGURES viii
LIST OF TABLES xv
LIST OF NOMENCLATURE xvii
Chapter
1 Introduction 1
1.1 General 1
1.2 Objective 2
1.3 Overview of the Thesis 2
2 Literature Review 4
2.1 Measurement of Heat Release Rate 4
2.2 Measurement of Smoke Obscuration 10
2.3 Measurement of Ignitability .13
3 Principle of Measurement 16
3.1 Heat Release Rate 16
3.2 ? Smoke Production Rate 17
iv
3.3 Mass Loss Rate 18
3.4 Effective Heat of Combustion 19
3.5 Carbon Dioxide (C0
)Yield 19
2
3.6 Carbon Monoxide (CO) Yield 21
3.7 Smoke Flow Rate 21
4 Apparatus 25
4.1 Cone Heater 25
4.1.1 Thermocouples 25
4.2 Exhaust System 29
4.3 Smoke Obscuration Measuring System 31
4.3.1 The Installation of Laser Photometer 31
4.4 Specimen Mounting 35
4.5 Gas Sampling 35
4.6 Spark Ignitor 39
4.7 Electronic Balance 39
4.8 Data Acquisition System 41
5 Calibration of Apparatus 43
5.1 Heat Release Rate Calibration 43
5.1.1 Determining the Gas Analyzer
Time Offsets 43
5.1.2 Determining Calibration Constant C 44
5.2 Heat Flux Calibration 46 v
5.2.1 Calibrating the Heater Thermocouples to
Actual Heat Flux Value 46
5.2.2 Checking the Uniformity of the
Heat Flux 51
5.3 Smoke Meter Calibration 52
5.3.1 Calibration of Neutral Density Filters 52
5.3.2 Smoke Meter Calibration 53
5.4 Pressure Transducer Calibration 55
5.5 System Calibration with PMMA 56
6 Experimental Observations and Results 64 6.1 Introduction 64
6.2 Tests and Samples 64
6.3 Test Preparation 67
6.3.1 Sample Preparation 67
6.3.2 Specific Fuel Factor 67
6.4 Test Observation and Results 68
6.4.1 Medium-density Fibreboard 69
6.4.2 Extruded Polystyrene Foam 84
6.4.3 High-density Polyethylene Board 90
6.5 Discussion 95
6.5.1 Heat Release Rate 96
6.5.2 Smoke Production Rate 97
6.5.3 Time to Ignition 97
<6.5.4 Mass Loss Rate 100
v i
Chapter Page 7 Conclusions and Recommendations 102
7.1 Conclusions 102
7.2 Recommendations for Further Work 103
REFERENCES 105
APPENDICES 109
I. TESTECH CONE CALORIMETER DATA ACQUISITION
SYSTEM CONTROLLER SOFTWARE 110
II DATA RECORDED OF CALIBRATION HEAT FLUX
VERSUS HEATER TEMPERATURE 127
III EXPERIMENTAL PROCEDURES 129
IV QUATTRO MACRO PROGRAMS FOR DATA ANALYSIS
AND REDUCTION 131
V INFORMATION FOR MAKING FIRE-RETARDED
SAMPLES 143
VI CALCULATING SPECIFIC FUEL FACTORS
FOR MATERIALS EVALUATED 144
VII TEST RESULTS(FIGURES) 145
LIST OF FIGURES IN APPENDIX VII 146
VIII TEST RESULTS (TABLES) 230
LIST OF TABLES IN APPENDIX VIII 231
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List of Figures
Figure Page
1 Modified OSU Box Apparatus for Measuring HRR 7
2 STFI Open-Test Apparatus for Measuring HRR 8
3 General View of TESTech cone calorimeter 9
4 NBS Smoke Chamber 11
5 ISO Ignitability Apparatus 15
6 TESTech cone calorimeter; Horizontal Orientation 26
7 TESTech cone calorimeter; Vertical Orientation 27
8 Section Through Cone Heater 28
9 Exhaust System 30
10 Smoke Obscuration Measuring System 32
11 Circuit Connection Drawing for Photodiode 33
12 Horizontal Specimen Holder 36
13 Vertical Specimen Holder 37
14 Gas Sampling Ring 38
15 Circuit for Spark Plug 40
16 Computer Screen for Data Acquisition System 42
17 Oxygen Analyzer Time Delay 45
18 Calibration Curve for Heater Temperature
versus Heat Flux (Horizontal Orientation) 50
19 Calibration Curve for Heater Temperature
versus Heat Flux (Vertical Orientation) 50
v i i i
20 The Curve of Photodiode Output Readings
versus Optical Density 54
21 Pressure Difference versus Output Voltage
of Pressure Transducer 56
2
22 PMMA Heat Release Rate at 50 kW/m
(Horizontal Orientation) 59
23 PMMA Mass Loss Rate at 50 kW/m2
(Horizontal Orientation) 59
24 PMMA Effective Heat of Combustion at 50 kW/m2 (Horizontal Orientation) 60
25 PMMA Smoke Production Rate at 50 kW/m2
(Horizontal Orientation) 60
26 PMMA Oxygen Consumption at 50 kW/m2
(Horizontal Orientation) 61
27 PMMA Carbon Dioxide Yield at 50 kW/m2
(Horizontal Orientation) 61
28 PMMA Carbon Monoxide Yield at 50 kW/m2
(Horizontal Orientation) 62
29 The FSC - UNB TESTech cone calorimeter 65
30 A Comparison of Medium Density Fibreboard(19mm Thick) Heat Release Rate at
Different Levels of Heat Flux (Horizontal Orientation) 70
31 A Comparison of Medium Density Fibreboard(19mm Thick) Mass Loss Rate at
Different Levels of Heat Flux
(Horizontal Orientation) 70
ix
33 A Comparison of Medium Density Fibreboard(19mm Thick) Smoke Production
Rate at Different Levels of
Heat Flux (Horizontal Orientation) 71
34 A Comparison of Medium Density Fibreboard(19mm Thick) Carbon Monoxide Yield at
Different Levels of Heat Flux (Horizontal Orientation) 72
35 A Comparison of Medium Density Fibreboard(19mm Thick) Carbon Dioxide Yield at
Different Levels of Heat Flux (Horizontal Orientation) 72
36 A Comparison of Medium Density Fibreboard(19mm Thick) Oxygen Consumption
at Different Levels
Heat Flux (Horizontal Orientation) 73
37 A Comparison of Medium Density Fibreboard(19mm Thick) Smoke Temperature at
Different Levels of
Heat Flux (Horizontal Orientation) 73
38 A Comparison of Medium Density Fibreboard(19mm Thick) Heat Release Rate at
Different Levels of Heat Flux
(Vertical Orientation) 74
39 A Comparison of Medium Density Fibreboard(19mm Thick) Mass Loss Rate at
Different Levels of Heat Flux
(Vertical Orientation) 74
x
41 A Comparison of Medium Density Fibreboard(19mm Thick) Smoke Production
Rate at Different Levels of
Heat Flux (Vertical Orientation) 75
42 A Comparison of Medium Density Fibreboard(19mm Thick) Carbon Monoxide Yield at
Different Levels of Heat Flux (Vertical Orientation) 76
43 A Comparison of Medium Density Fibreboard(19 mm Thick) Carbon Dioxide Yield at
Different Levels of Heat Flux (Vertical Orientation) 76
44 A Comparison of Medium Density Fibreboard(19mm Thick) Oxygen Consumption
at Different Levels
Heat Flux (Vertical Orientation) 77
45 A Comparison of Medium Density Fibreboard(19mm Thick) Smoke Temperature
at Different Levels of
Heat Flux (Vertical Orientation) 77
46 A Comparison of Fire-retarded Fibreboard(13 mm Thick) With One Not Fire-
retarded for Heat Release Rate
at 50 kW/m2 (Horizontal Orientation) 80
47 A Comparison of Fire-retarded Fibreboard(13 mm Thick) With One Not Fire-
retarded for Mass Loss Rate
at 50 kW/m2 (Horizontal Orientation) 80
xi
48 A Comparison of Fire-retarded Fibreboard(13 mm Thick) With One Not Fire-retarded for
Effective Heat of Combustion at 50 kW/m2 (Horizontal Orientation) 81
49 A Comparison of Fire-retarded Fibreboard(13 mm Thick) With One Not Fire-
retarded for Smoke Production Rate
at 50 kW/m2 (Horizontal Orientation) 81
50 A Comparison of Fire-retarded Fibreboard(13 mm Thick) With One Not Fire-
retarded for Carbon Monoxide Yield
at 50 kW/m2 (Horizontal Orientation) 82
51 A Comparison of Fire-retarded Fibreboard(13 mm Thick) With One Not Fire-
retarded for Carbon Dioxide Yield
at 50 kW/m2 (Horizontal Orientation) 82
52 A Comparison of Fire-retarded Fibreboard(13 mm Thick) With One Not Fire-
retarded for Oxygen Consumption
at 50 kW/m2 (Horizontal Orientation) 83
53 A Comparison of Fire-retarded Fibreboard (13 mm Thick) With One Not Fire-
retarded for Smoke Temperature
at 50 kW/m2 (Horizontal Orientation) 83
54 A Comparison of Extruded Polystyrene Foam Heat Release Rate at Different Levels of
Heat Flux (Horizontal Orientation) 85
55 A Comparison of Extruded Polystyrene Foam Mass Loss Rate at
Different Levels of Heat Flux
(Horizontal Orientation) 85
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56 A Comparison of Extruded Polystyrene Foam Effective Heat of
Combustion at Different Levels of
Heat Flux (Horizontal Orientation) 86
57 A Comparison of Extruded Polystyrene Foam Smoke Production
Rate at Different Levels of
Heat Flux of (Horizontal Orientation) 86
58 A Comparison of Extruded Polystyrene Foam
Carbon Monoxide Yield at Different Levels of Heat Flux (Horizontal Orientation)
87
59 A Comparison of Extruded Polystyrene Foam Carbon Dioxide Yield at Different Levels of
Heat Flux (Horizontal Orientation) 87
60 A Comparison of Extruded Polystyrene Foam Oxygen
Consumption at Different Levels of
Heat Flux (Horizontal Orientation) 88
61 A Comparison of Extruded Polystyrene Foam Smoke Temperature
at Different Levels of
Heat Flux (Horizontal Orientation) 88
62 A Comparison of High-density Polyethylene Board Heat Release Rate at Different Levels
of Heat Flux (Horizontal Orientation) (91)
63 A Comparison of High-density Polyethylene Board Mass Loss Rate at
Different Levels of Heat Flux
(Horizontal Orientation) 91
x i i i
64 A Comparison of High-density Polyethylene Board Effective Heat of
Combustion at Different Levels of
Heat Flux (Horizontal Orientation) 92
65 A Comparison of High-density Polyethylene Board Smoke Production
Rate at Different Levels of
Heat Flux (Horizontal Orientation) 92
66 A Comparison of High-density Polyethylene Board Carbon Monoxide Yield at Different
Levels of Heat Flux (Horizontal Orientation) 93
67 A Comparison of High-density Polyethylene Board Carbon Dioxide Yield at Different
Levels of Heat Flux (Horizontal Orientation) 93
68 A Comparison of High-density Polyethylene Board Oxygen
Consumption at Different Levels of
Heat Flux (Horizontal Orientation) 94
69 A Comparison of High-density Polyethylene Board Smoke Temperature
at Different Levels of
Heat Flux (Horizontal Orientation) 94
10 Time to Ignition versus Heat Flux for Medium-density
Fibreboard(19mm Thick) on Both Orientations 99
71 Time to Ignition versus Heat Flux for High-density
Polyethylene Board and Extruded Polystyrene Foam 99
xiv
List of Tables
Table Page
1 Heat Release Rate of Propane 46
2 Calibration for the Instrument Constant , C 47
3 Calibration of Heat Flux as a Function of
Heater Temperature 49
4 Heat Flux Uniformity 51
5 Calibration of Neutral Density Filters 53
6 Calibration Results for Photometer 54
7 Pressure Transducer Calibration Results 55
8 Calibration Report for Black PMMA 58
9 Comparison of Black PMMA Calibration
Results with Standard Values 63
10 A List of Samples and Tests 66
11 Comparison of Test Values with Literature Values
for Medium-density Fibreboard 78
12 Comparison of Test Values with Literature Values for Extruded Polystyrene Foam 89
13 Comparison of Test Values with Literature Values for High-density Polyethylene
Board 95
14 A Summary of Time to Ignition for All Tests 98
Al Data Recorded of Calibration Heat Flux versus Heater
Temperature for Horizontal Orientation 127 xv
Data Recorded of Calibration Heat Flux versus Temperature for Vertical Orientation
The Information for Fire-retarded Samples
Exhaust duct area, m2
List
of
Nome
nclat
ure A
a Orifice plate throat area, m2
Exposed surface area of specimen, 0.01 m2
A
s
b Stoichiometri
c factor
C Calibration constant for the measurement of heat release rate Q Discharge coefficient
On Discharge coefficient for determining mass flow rate
CO(t) Carbon monoxide yield at time t, kg/kg
C0
(t) Carbon dioxide yield at time t, kg/kg
2
Cp Specific heat of exhaust gases, kJ/mole K
C
Discharge coefficient for determining volumetric flow rate
v
D Diameter of exhaust duct, m
d Diameter of orific
e plate throat, m
Dl Optical density per path length
gc Universal acceleration of gravity
Ah
c Net heat of combustion, kJ/kg
Ahceff Effective heat of combustion, kJ/kg
Ahceff (0 Effective heat of combustion at time t, kJ/kg
h Actual laser beam intensity at wavelength X Unattenuated laser beam intensity at wavelength X
k Light extinction coefficient, m1
K Flow coefficient