FPRF Final Report Volume 1

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Validation of a Smoke Detection

Performance Prediction MethodologyVolume 1. Characterization of incipient fire sources

Prepared by:

Matthew Brookman, Frederick W. Mowrer and James A. MilkeUniversity of Maryland

Pravinray Gandhi

Underwriters Laboratories Inc.

October 2008 Fire Protection Research Foundation


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FOREWORD

This report presents the results of a Foundation project whose goal was to develop avalidated engineering methodology to calculate and accurately predict the responsetime of spot-type and aspirated smoke detection systems exposed to incipient fires andgrowing fires. The report, divided into four volumes, describes the test methods, testresults, computer simulations and analyses used for this project, which addresses thevalidation of a smoke detection performance prediction methodology.

The four volumes of this report include:

Volume 1, which addresses the characterization of the heat and smoke releaserates of eight incipient fire sources selected for this project;

Volume 2, which addresses the large-scale room fire tests conducted as part ofthis project;

Volume 3, which addresses evaluation of smoke detector performance in the

large-scale room fire tests conducted as part of this project;Volume 4, which addresses comparisons of current FDS smoke detectionprediction methodologies with actual smoke detector performance in the large-scale room fire tests.

The Research Foundation expresses gratitude to the project sponsors and technicalpanelists listed on the following page.

The content, opinions and conclusions contained in this report are solely those of theauthors.


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Validation of a Smoke Detection Performance Prediction

MethodologyResearch ProjectTechnical Panel

Shane Clary, Bay Alarm Company

Kenneth Dungan, PLC Foundation

Jay Ierardi, R.W. Sullivan Engineering

Kevin McGrattan, National Institute of Standards and Technology

Dan Nichols, NYS Code Enforcement and Administration

Ali Rangwala, Worcester Polytechnic Institute

Joseph Su, National Research Council of Canada

Principal Sponsors

Honeywell Life Safety

National Electrical Manufacturers Association

Siemens Building Technologies, Inc.

SimplexGrinnell


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Validation of a Smoke Detection Performance Prediction Methodology

Volume 1. Characterization of incipient fire sources

Prepared for:

Kathleen AlmandFire Protection Research Foundation

1 Batterymarch ParkQuincy, MA 02169

Prepared by:

Matthew Brookman, Frederick W. Mowrer and James A. Milke

University of Maryland

Pravinray Gandhi


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Validation of a Smoke Detection Performance Prediction Methodology Volume 1October 10, 2008 p. ii

Executive Summary

This report, divided into four volumes, describes the test methods, test results, computersimulations and analyses used for this project, which addresses the validation of a smoke

detection performance prediction methodology. This project was conducted jointly by the

University of Maryland (UM) and Underwriters Laboratories, Inc., (UL) under the auspices ofthe Fire Protection Research Foundation (FPRF). The financial and technical support of the

FPRF, the project sponsors and the project technical panel are gratefully acknowledged.

The four volumes of this report include:

Volume 1, which addresses the characterization of the heat and smoke release rates ofeight incipient fire sources selected for this project;

Volume 2, which addresses the large-scale room fire tests conducted as part of thisproject;

Volume 3, which addresses evaluation of smoke detector performance in the large-scaleroom fire tests conducted as part of this project;

Volume 4, which addresses comparisons of current FDS smoke detection predictionmethodologies with actual smoke detector performance in the large-scale room fire tests.

The overall objective of this project has been to evaluate the capabilities of the current release

version (5.1.0) of the Fire Dynamics Simulator (FDS) to predict smoke detector activation inresponse to relatively low energy incipient fire sources. The project was subdivided into four

tasks, consistent with the four volumes included in this report.

The first task was to characterize the heat and smoke release rates of eight incipient fire sourcesselected for this project. The incipient fire sources are described in Table E1; the fire sources

include four flaming fire sources and four smoldering/pyrolyzing fire sources. The heat and

smoke release rates of these incipient fire sources were measured in the same IMO intermediate


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room fire tests. The second set of large-scale tests was conducted in a 7.2 m (24 ft) long by 7.2

m (24 ft) wide by 3.0 m (10 ft) high room constructed specifically for this project to represent a

mechanically ventilated commercial space. This room was provided with mechanical injectionventilation and a ceiling return air plenum to represent a typical commercial type of installation.

Three replicate tests were conducted with each of the eight incipient fire sources at nominal

mechanical ventilation rates of 6 and 12 air changes per hour; two replicate tests were conductedwith each of the incipient fire sources under unventilated conditions in this room. Thus, 64 fire

tests were conducted in the ventilated room, for a total of 88 large-scale fire tests in the two

rooms. A matrix showing the designations of the 88 large-scale tests is provided in Table E2.

Table E1. Incipient fire sources

Fuel source Ignition source Fire type

Shredded office paper Small flame (50 W) Flaming

Flexible PU foam /microfiber fabric

Small flame (50 W) Flaming

Flexible PU foam /

microfiber fabric

Hotplate Smoldering/pyrolysis

Ponderosa pine Hotplate Smoldering/pyrolysis

Cotton linen fabric Hotplate Smoldering/pyrolysis

PVC wire Electric overcurrent Smoldering/pyrolysis

Computer case Small flame (UL 94) Flaming

Printed circuit board Small flame (ATIS T1.319) Flaming

Table E2. Matrix of large-scale room fire test designations

Incipient fire source Unventilated

room

Ventilated room

6 ach 12 ach 0 ach

Sh dd d ffi 1 2 3 25 26 27 49 50 51 73 74


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Validation of a Smoke Detection Performance Prediction Methodology Volume 1October 10, 2008 p. iv

detection systems from one manufacturer. The response of these different smoke detection

devices during these tests provides a basis for evaluating the current capability of FDS to predict

smoke detector activation in response to incipient fire sources. Volume 2 of this report describesthe details of the large-scale room fire tests and provides the instrumentation and detection data

from these 88 fire tests. More than 1,200 graphs have been developed to illustrate the results of

these 88 tests; these graphs are too voluminous to print, so they are provided on electronic mediain Excel files associated with each test. This large-scale room fire test data set should prove

useful for future smoke transport and smoke detection validation exercises as well as for this one.

The third task was to evaluate smoke detector performance during the large-scale fire tests. For

this task, the response of the spot-type and aspirated smoke detectors during the fire tests was

evaluated and characterized. These results were then compared with methodologies available in

the fire safety literature for predicting the activation of smoke detectors. Volume 3 of this reportdescribes the details of these comparisons.

One objective of this project has been to develop the means, based on experimental data, to

estimate the response of smoke detectors using the simulated results of the smoke conditions

computed by FDS. Smoke conditions estimated by FDS throughout the domain includetemperature, velocity and mass fraction of smoke (which can be related to light obscuration or

visibility). One of the relatively unique aspects of this study is an examination of the role ofventilation conditions in identifying surrogate measures to predict smoke detector response.

Within the last 10 years, there have been five significant studies examining the response ofsmoke detectors. These studies, examined as part of this project, include:

Kemano by the National Research Council of CanadaNaval Research Laboratory and Hughes Associates tests for shipboard applications

Home Smoke Alarm Project by NIST

Smoke Characterization Project by Underwriters Laboratories for the Fire Protection


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In the case of flaming fires in ventilated rooms, the 80th

percentile values of the obscuration

levels differ appreciably for the two detection technologies. For flaming fires with ventilation,

the 80th percentile values of the obscuration level for photoelectric smoke detectors were 4.3 to4.9 %/ft. In contrast, the 80

thpercentile values of the obscuration level for ionization smoke

detectors were 8.0 to 10.3 %/ft, although it is noted that the 10.3% is based on only two tests

conducted at a forced ventilation rate of 12 ACH. As such, a possible guideline of obscurationlevels for photoelectric detectors could be 5 %/ft for ventilation rates ranging from 6 to 12 ACH.

For ionization detectors, the 8 %/ft value appears to be an appropriate guideline considering only

the results from the tests with 6 ACH. With the limited number of tests conducted at 12 ACHwhere ionization detectors responded, a guideline to estimate their response cannot be suggested.

For non-flaming fires without ventilation, the 80th

percentile values of the obscuration levels

ranged from 4.4 to 18.5 %/ft for ionization smoke detectors and 1.6 to 12.1 %/ft for photoelectricsmoke detectors. The 80

thpercentile values of the obscuration levels for non-flaming fires with

ventilation were all less than 1 %/ft in this study and approximately 5 %/ft for ionization

detectors in the NRL study. Given the limited data in this area, a recommendation for

establishing a guideline of only 1 %/ft is questionable, especially in light of the difference in

results obtained from experiments conducted as part of this study and the NRL study. Untilfurther data is obtained, a value in excess of 1 %/ft is recommended and should perhaps be as

large as 2.5 %/ft.

The temperature rise at the time of detection response for flaming fires with no forced ventilation

is highly dependent on the detection technology. A temperature rise of approximately 5 K canbe suggested as a reasonable conservative guideline for ionization detectors, though should be

greater than 5 K, e.g. 15 K given the measurements obtained in the NRL and NIST tests. For

non-flaming fires and all fires with forced ventilation a temperature rise of approximately 3 Kappears to be a reasonable guideline to estimate smoke detector response of either technology.

Because the velocities associated with the forced ventilation provided in the test room were


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compared with the experimental results. Volume 4 of this report describes the details of these

simulations and comparisons.

The baseline FDS simulations of the room tests were performed with a uniform grid size of 10

cm (4 in.). This resulted in a total number of 233,280 computational cells in both the

unventilated enclosure domain, which had dimensions of 10.8 m (108 cells) by 7.2 m (72 cells)by 3.0 m (30 cells) high, as well as in the ventilated enclosure domain, which had dimensions of

7.2 m (72 cells) by 7.2 m (cells) by 4.5 m (45 cells) high. On a single-processor PC, it took a

few hours to run the 5 to 10 minute simulations of the flaming fire sources to a few days to runthe 80 to 90 minute simulations of the smoldering fire sources at this resolution. Doubling the

grid resolution from 10 cm (4 in.) to 5 cm (2 in.) changes these run times from a few days to a

number of weeks and consequently would be unreasonable for most applications.

It is difficult to generalize about the comparisons of the FDS simulations of detector activation in

the room tests with the actual room test detection data because of the wide range of results. In

some cases, the simulated and actual smoke conditions at the detection stations were relatively

close to one another and within the experimental scatter, while in other cases, the simulated

smoke concentrations exceeded the measured smoke concentrations by relatively large margins.

There are at least three potentially significant sources of uncertainty associated with FDSsimulation of smoke detector performance in room fire scenarios:

Uncertainties in the initial and boundary conditions specified for a scenario, includinguncertainties in specification of the fire heat and smoke release rate histories and inspecification of the mechanical ventilation;

Uncertainties in the calculations performed by FDS to simulate heat and smoke transport;Uncertainties in the empirical models FDS currently uses to calculate smoke detectorresponse and to predict smoke detector activation.


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Only a single fire source could be specified, which did not allow separate specification of

an ignition source and other fuels subsequently ignited;

The smoke release rate could not vary independently of the heat release rate, so productswith variable smoke yields could not be modeled properly;

Smoldering and pyrolyzing smoke sources that produce substantial quantities of smokebut little heat could not be modeled properly.

As a result of these limitations, the developers of the FDS model incorporated a new algorithm

that permits the user to specify smoke release independently of heat release. This new featurewas used to specify smoke release rates for this project.

The primary findings of this project can be summarized as follows:

The smoke release rates of eight different incipient fire sources, including four flamingsources, three smoldering sources and one overheated electrical wire, have been

measured under well-characterized conditions in replicate bench-scale tests conducted in

the IMO intermediate scale calorimeter at Underwriters Laboratories in Northbrook, IL.The primary smoke signature of interest in this project was the obscuration of visiblelight. Additional data was gathered during the bench-scale tests, including particle count

density, mean particle diameter, carbon monoxide production and carbon dioxide

production. This additional data may be of use in future investigations, but has not been

analyzed for this project.

Smoke obscuration was measured in the exhaust duct of the IMO intermediate scalecalorimeter by projecting a white light beam across the diameter of the exhaust duct onto

a photocell and measuring the change in voltage at the photocell caused by smokeparticles in the light beam.

Smoke release rates are characterized in units of m2/s, where the smoke release rate is

l l t d th d t f th k ti ti ffi i t k (-1

) b th l t i


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m

sk

TSR

m

The average smoke yield during a test is calculated as the quotient of the mass of smokereleased to the fuel mass loss during a test:

f

ss

m

my

When calculated in this way, the average smoke yields obtained for the eight incipientsources in the IMO apparatus are shown in Table E3 along with other data from the IMO

tests. These data provide an indication of the variability in the replicate tests.

When this project started, smoke production was calculated in FDS only in terms ofconstant smoke yield factors tied to the specified heat release rate through the mixture

fraction model used by FDS. During this project, it became apparent that smoke yields

for the eight incipient sources are not constant and that characterizing smoke productionin terms of a constant smoke yield factor would not produce accurate smoke production

or transport results in FDS for these incipient fire sources.

During this project, the developers of FDS implemented a new method to specify smokeproduction independently of heat release. Called the species ID method, this methodwas used throughout this project to specify smoke production in FDS for both the IMO

test simulations and the room fire simulations.

The bench-scale tests conducted in the IMO apparatus were simulated in FDS as one

means to validate the capabilities of FDS to model smoke production and transport. Forthese FDS simulations, a uniform grid size of 2.5 cm was used. These simulations of the

IMO tests showed that the calculated smoke quantity transported past the smoke eye in

the e ha st d ct as similar to the q antit of smoke released from the f el package as


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Table E3. Summary of data obtained from tests conducted in IMO apparatus

Sample Description Mode Peak HRR Peak SRR Smoke Yield Total SR Total HR

(kW) (m /s) (g/g) (m) (MJ)

Shredded Paper-1 Flaming 7.76 1.350 0.094 110.5 0.388

Shredded Paper-2 Flaming 8.91 0.990 0.083 105.8 0.612Shredded Paper-3 Flaming 12.49 2.000 0.097 117.4 0.589

Shredded Paper Average 9.72 1.447 0.091 111.2 0.530

PU Foam/Microfiber-1 Flaming 8.54 0.432 0.094 74.2 1.896



PU Foam/Microfiber Average 9.85 0.486 0.095 79.7 2.037

Circuit Board-1 Flaming 1.90 0.534 0.215 22.0 0.826Circuit Board-2 Flaming 2.41 0.491 0.221 20.3 0.924

Circuit Board-3 Flaming 2.59 0.587 0.319 24.7 1.120

Circuit Board Average 2.30 0.537 0.252 22.3 0.957

Computer Case-1 Flaming 0.00 0.119 0.785 9.2 0.000



Computer Case Average 0.45 0.219 0.877 15.9 0.069PU Foam/Microfiber-1 Smoldering N/A 0.066 0.085 39.9 N/A

PU Foam/Microfiber-2 Smoldering N/A 0.073 0.089 43.8 N/A

PU Foam/Microfiber 3 Smoldering N/A 0 040 0 073 36 2 N/A


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Table E4. Variation in FDS modeling results of smoke measurement in IMO apparatus

Fuel Source Model Output to Input Model Output to Test

Shredded Office Paper -0.8% 4.8%

PU Foam with Micro-

fiber Fabric -5.4% -4.7%

Printed Circuit Board 0.1% -1.6%

Computer Case ABS

Plastic 4.3% 4.7%

PU Foam with Micro-

fiber Fabric -3.1% -1.5%

Ponderosa Pine -1.6% 1.9%

Cotton Linen Fabric -0.9% 1.3%

PVC Insulated Wire -1.6% -5.2%

Flaming

Smoldering

Table E5. Peak obscuration values and times in the IMO physical tests and FDS simulations.


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The responses of the two brands of photoelectric detectors used in this project were

generally consistent with each other, but the levels of smoke obscuration reported by

these detectors was not always consistent with the smoke obscuration levels measured atthe adjacent detection stations. This may be due to the different methods used to measure

smoke obscuration by the detectors, which use light reflection, and by the adjacent

photocell assemblies, which use light obscuration.

The levels of smoke obscuration reported by the spot detectors are based on correlationsdeveloped from testing in the UL smoke box using only a single smoke source, a

smoldering cotton wick. This correlation has not been demonstrated for the smoke

sources used in this project; this may account for at least some of the differences betweenthe smoke obscuration levels reported by the spot detectors and those measured by the

adjacent photocell assemblies.

Based on analysis of the smoke detector data from the room fire tests in this project, thesmoke obscuration at detection, represented in %/ft and based on the 80

thpercentile

values, are shown in Table E6 for the different ventilation conditions, fire conditions anddetector types.

Table E6. Smoke obscuration at detection in room tests based on 80th

percentile values.

12 ACH6 ACH

1?

Insuff. Data

5

Insuff. Data

Non-flaming

Flaming

1?10Photoelectric

1?12Ionization

58Photoelectric

88Ionization

Ventilated

Unventilated

12 ACH6 ACH

1?

Insuff. Data

5

Insuff. Data

Non-flaming

Flaming

1?10Photoelectric

1?12Ionization

58Photoelectric

88Ionization

Ventilated

Unventilated


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Based on analysis of the smoke detector data from the room fire tests in this project,

substantial errors are indicated in using simplistic guidelines of obscuration and

temperature rise based on 80th percentile values. The values reported in the previoustables both overestimate and underestimate response times in specific tests.

These errors may be reduced through use of a dual parameter approach, e.g. obscurationand velocity in unventilated rooms:

o Flaming fires, photoelectric detectors: 5.5-9.5 %/ft and 0.14-0.33 m/so Non-flaming fires, photoelectric detectors: 1.5-2.5 %/ft and 0.03-0.07 m/s

The near-ceiling velocity of ventilation in the ventilated room tests with 6 and 12 ACH

exceeds the velocity of the ceiling jet from the incipient fires in these tests.The near-ceiling velocity field caused by the mechanical injection of air at 6 and 12 ACHhas not been experimentally characterized.

The responses of the aspirated systems in the 64 tests in the ventilated room have beensummarized in Excel spreadsheets, but have not yet been analyzed. The data from the

aspirated systems has not yet been synchronized with the other experimental data due to

technical difficulties with the synchronization process.

Baseline FDS simulations have been conducted for 32 different room fire scenarios

involving the 8 incipient fire sources under 4 different conditions, including unventilatedtests conducted in the UL 217/268 standard smoke room, unventilated tests conducted in

the ventilated room constructed for this project, and ventilated tests conducted at 6 and 12air changes per hour in this ventilated room. For the baseline FDS simulations, a 10 cm

uniform grid was used, resulting in a total of 233,280 computational cells for both the

unventilated and ventilated enclosures. For the baseline FDS simulations, the specifiedsmoke release rate was based on measurements of smoke release rate in the IMO bench-

scale tests and was not corrected for transport lag.

Additional FDS simulations have been conducted for a few scenarios using the multi-mesh feature of FDS to provide a higher level of resolution of 5 cm in the fire plume and

ceiling jet regions of the two enclosures, but these simulations have not yet beend ith th i t l d t th b li FDS i l ti Th lt d


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obscuration levels is smoke deposition to room surfaces, which is not currently addressed

in FDS.

The levels of smoke obscuration measured by the photocell assemblies at the detectionstations during the mechanically ventilated tests were low in comparison with the levels

of smoke obscuration reported by the adjacent smoke detectors and in comparison with

the levels of smoke obscuration predicted by the associated FDS simulations. The reasonfor this has not yet been determined.

The mechanically ventilated tests conducted at 6 and 12 ACH demonstrated conditionsdifferent from those observed in the unventilated tests. In particular, smoke did not

readily transport past the plane defined by the line between the two injection louvers atthe center of the room. Instead, the smoke tended to stack up on the fire side of this

plane, suggesting that the mechanical injection of air was acting as an air curtain.

Qualitatively, this was observed in both the room fire tests as well as in the baseline FDS

simulations. This also had the effect of delaying smoke detector response on thedownstream side of the injection louvers. The impact of mechanical ventilation on smoke

detector response warrants further investigation.

Recommendations for further study include:

Develop the relationship between light scattering and light obscuration for fuels ofprimary interest (UL 217 fuels, PU foam, etc.) as a means to resolve the differences insmoke obscuration levels reported by the smoke detectors and those measured by the

adjacent photocell assemblies.

Perform additional FDS simulations at higher resolutions to evaluate the effects onpredicted smoke obscuration levels.

Perform additional mechanically ventilated room tests to characterize the velocity fieldcaused by the injection of air through representative air louvers.

Establish methods to more accurately simulate the injection of air through representativei l i FDS


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Acknowledgements

The authors would like to acknowledge the financial and technical support provided by the FireProtection Research Foundation, the project sponsors and the members of the project technical

panel. The authors would also like to acknowledge the assistance provided by Alyson Blair,

Allison Carey and Andrew Laird, who were undergraduate students in the Department of FireProtection Engineering at the University of Maryland when this project was conducted as well as

the assistance and technical support of Tom Fabian, Tom Lackhouse and Dan Steppan of UL.

Special thanks to Scott Lang of System Sensor for his technical support throughout this project.


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Validation of a Smoke Detection Performance Prediction Methodology

Volume 1. Characterization of incipient fire sources

Prepared for:

Kathleen AlmandFire Protection Research Foundation

1 Batterymarch ParkQuincy, MA 02169

Prepared by:

Matthew Brookman, Frederick W. Mowrer and James A. Milke

University of Maryland

Pravinray Gandhi


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TABLE OF CONTENTSPage

Executive Summary ii

Acknowledgements xiv

1.0 Introduction 1

2.0 Fuel Source Characterization 2

2.1 IMO Apparatus Instrumentation 2

2.2 Experimental Calculations 4

2.3 Experimental Procedures 6

2.3.1 Shredded Office Paper 6

2.3.2 PU Foam with Micro-fiber Fabric (Flaming) 8

2.3.3 Printed Circuit Board 9

2.3.4 Computer Case ABS Plastic 10

2.3.5 PU Foam with Micro-fiber Fabric (Smoldering) 11

2.3.6 Ponderosa Pine Sticks 13

2.3.7 Cotton Linen Fabric 14

2.3.8 PVC Insulated Wire 15

3.0 Experimental Results 15

3.1 Shredded Office Paper 16

3.2 PU Foam with Micro-fiber Fabric (Flaming) 20


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4.6 Ponderosa Pine Sticks 51

4.7 Cotton Linen Fabric 524.8 PVC Insulated Wire 53

5.0 FDS Modeling of IMO Tests 54

5.1 Model Configuration 55

5.2 Model Input Calculations 56

5.3 Model Output Calculations 57

5.4 Model Results and Analysis 58

5.4.1 Shredded Office Paper 58

5.4.2 PU Foam with Micro-fiber Fabric (Flaming, Mixture Fraction Model) 62

5.4.3 PU Foam with Micro-fiber Fabric (Flaming, Species ID Method) 65

5.4.4 Printed Circuit Board 69

5.4.5 Computer Case ABS Plastic 735.4.6 PU Foam with Micro-fiber Fabric (Smoldering) 76

5.4.7 Ponderosa Pine Sticks 80

5.4.8 Cotton Linen Fabric 83

5.4.8 PVC Insulated Wire 86

6.0 Summary and Conclusions 89

7.0 References 91

Appendix A: Summary of IMO Apparatus Test Results A-1


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List of FiguresPage

Figure 1. Schematic diagram of the IMO intermediate-scale calorimeter apparatus. 3

Figure 2. Photos of shredded paper fire source assembly 7

Figure 3. Photos of PU foam/microfiber fire source assembly 8Figure 4. Photos of PC board fire source assembly 9

Figure 5. Line burner attached to ring stand. 9

Figure 6. Photos of PC board fire source assembly during testing. 10Figure 7. Photos of computer case fire source assemblies. 11

Figure 8. Photos of smoldering PU foam fire source assembly. 12

Figure 9. Hotplate temperature profile (UL 217). 12

Figure 10. Photos of Ponderosa pine stick fire source assembly. 13Figure 11. Photos of cotton linen fabric fire source assembly. 14

Figure 12. Photos of PVC insulated wire fire source assembly. 15

Figure 13. Shredded office paper mass loss. 16

Figure 14. Shredded office paper heat release rate. 16

Figure 15. Shredded office paper smoke release rate. 17Figure 16. Shredded office paper particle count density. 17

Figure 17. Shredded office paper mean particle diameter. 18Figure 18. Shredded office paper carbon monoxide output. 18

Figure 19. Shredded office paper carbon dioxide output. 19

Figure 20. Flaming PU foam with micro-fiber fabric mass loss. 20Figure 21. Flaming PU foam with micro-fiber fabric heat release rate. 20

Figure 22. Flaming PU foam with micro-fiber fabric smoke release rate. 21

Figure 23. Flaming PU foam with micro-fiber fabric particle count density. 21Figure 24. Flaming PU foam with micro-fiber fabric mean particle diameter. 22Figure 25. Flaming PU foam with micro-fiber fabric carbon monoxide output. 22

Figure 26 Flaming PU foam with micro-fiber fabric carbon dioxide output 23


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Figure 44. Smoldering PU foam w/ micro-fiber fabric carbon monoxide output. 33

Figure 45. Smoldering PU foam w/ micro-fiber fabric carbon dioxide output. 34

Figure 46. Ponderosa pine smoke release rate. 35Figure 47. Ponderosa pine particle count density. 35

Figure 48. Ponderosa pine mean particle diameter. 36

Figure 49. Ponderosa pine carbon monoxide output. 36Figure 50. Ponderosa pine carbon dioxide output. 37

Figure 51. Cotton linen fabric smoke release rate. 38

Figure 52. Cotton linen fabric particle count density. 38Figure 53. Cotton linen fabric mean particle diameter. 39

Figure 54. Cotton linen fabric carbon monoxide output. 39

Figure 55. Cotton linen fabric carbon dioxide output. 40

Figure 56. PVC insulated wire smoke release rate. 41Figure 57. PVC insulated wire particle count density. 41

Figure 58. PVC insulated wire mean particle diameter. 42

Figure 59. PVC insulated wire carbon monoxide output. 42

Figure 60. PVC insulated wire carbon dioxide output. 43

Figure 61. Photos of shredded office paper test. 44Figure 62. Photos of flaming PU foam with micro-fiber fabric test. 45

Figure 63. Remains of PU foam fuel package near end of test. 46Figure 64. Photo of PC boards during testing. 48

Figure 65. Photo of computer case ABS plastic test. 50

Figure 66. Photos of cotton linen fabric during and after test. 52Figure 67. Photo of cotton linen fabric during test. 52

Figure 68. Photo of PVC insulated wire laminar during test. 53

Figure 69. IMO intermediate-scale hood in FDS. 55Figure 70. Shredded office paper heat release rate. 58Figure 71. Shredded office paper extinction coefficient. 59

Figure 72 Shredded office paper obscuration 59


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Figure 90. Printed circuit board model input and output. 71

Figure 91. Printed circuit board total smoke. 72

Figure 92. Computer case ABS plastic heat release rate. 73Figure 93. Computer case ABS plastic extinction coefficient. 73

Figure 94. Computer case ABS plastic obscuration. 74

Figure 95. Computer case ABS plastic smoke release rate. 74Figure 96. Computer case model input and output. 75

Figure 97. Computer case total smoke. 75

Figure 98. Smoldering PU foam w/ micro-fiber fabric extinction coefficient. 77Figure 99. Smoldering PU foam w/ micro-fiber fabric obscuration. 77

Figure 100. Smoldering PU foam w/ micro-fiber fabric smoke release rate. 78

Figure 101. Smoldering PU foam w/ micro-fiber fabric model input and output. 78

Figure 102. Smoldering PU foam w/ micro-fiber fabric total smoke. 79Figure 103. Ponderosa pine extinction coefficient. 80

Figure 104. Ponderosa pine obscuration. 80

Figure 105. Ponderosa pine smoke release rate. 81

Figure 106. Ponderosa pine model input and output. 81

Figure 107. Ponderosa pine total smoke. 82Figure 108. Cotton linen fabric extinction coefficient. 83

Figure 109. Cotton linen fabric obscuration. 83Figure 110. Cotton linen fabric smoke release rate. 84

Figure 111. Cotton linen fabric model input and output. 84

Figure 112. Cotton linen fabric total smoke. 85Figure 113. PVC insulated wire extinction coefficient. 86

Figure 114. PVC insulated wire obscuration. 87

Figure 115. PVC insulated wire smoke release rate. 87Figure 116. PVC insulated wire model input and output. 88Figure 117. PVC insulated wire total smoke. 88


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List of TablesPage

E1. Incipient fire sources iii

E2. Matrix of large-scale room fire test designations iii

E3. Summary of data obtained from tests conducted in IMO apparatus ixE4. Variation in FDS modeling results of smoke measurement in IMO apparatus x

E5. Peak obscuration values and times in the IMO physical tests and FDS simulations. x

E6. Smoke obscuration at detection in room tests based on 80th percentile values. xiE7. Temperature rise at detection in room tests based on 80th percentile values. xi

1. Hotplate Temperature (UL 217) 12

2. Comparison of Total Smoke Produced in IMO Tests and FDS Simulations 90

3. Peak Smoke Release Rate Model Input v. Model Output 90


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Validation of a Smoke Detection Performance Prediction Methodology Volume 1October 10, 2008 p. 1

1.0 Introduction

This volume of this report describes the experimental and analytical methods used tocharacterize the heat and smoke release rates of eight different incipient fire sources. Thesecharacterizations are part of a larger project to evaluate the capabilities of the current version

(5.1.0) of the Fire Dynamics Simulator (FDS) model to predict smoke detector activation. FDS

is a computational fluid dynamics model of fire development under ongoing development at the

Building and Fire Research Laboratory of the National Institute of Standards and Technology.

The experimental research described in this volume of this report was performed in the Fire

Protection Department at Underwriters Laboratories, Inc., in Northbrook, Illinois. Computer

modeling was performed at the University of Maryland, College Park, within the Department ofFire Protection Engineering in the A. James Clark School of Engineering using the UL FireModeling Lab. These computer simulations were conducted using Fire Dynamics Simulator

(FDS) version 5.1.0 and Smokeview version 5.

The purpose of this research is to provide guidance on methods to characterize incipient fuel

sources to be used in simulations using the Fire Dynamics Simulator (FDS) computer model, aswell as to evaluate the capability of FDS to simulate the relevant phenomena for predicting

smoke detector activation. The initial objective is the development of a process to characterizeboth flaming and smoldering fuel sources for input into FDS. Subsequently, FDS modeling of

the previous process is studied to evaluate the ability of the program to accurately reproduce theappropriate phenomena. Finally, the variations between the models and the initial

characterization are quantified to evaluate the accuracy of the process.

The focus of this research is on flaming and smoldering incipient fires from sources that are

common to commercial occupancies. This research is broken up into two phases. Phase 1 of theproject examines the characteristics of each of the fuel sources chosen for evaluation. Phase 2 of

the project focuses on the validation of the specific parameters in FDS that will determine the

output of the models. These phases are developed further in the subsections to follow.

Each of the eight fuel sources chosen for this project is characterized in ULs IMO intermediate


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Upon completion of Phase 1, a model of the UL IMO intermediate-scale calorimeter is created

using FDS and each of the fuel package fire test scenarios is simulated. A grid resolution study

is performed and the model is instrumented similarly to the original experiment. The datacollected from the original experiments is used to determine the uncertainty and the level of

accuracy required from these models.

The fuel characteristics determined under the intermediate-scale calorimeter are used in the input

file of FDS. The eight sources are modeled using a species ID for the smoke so that the smokegeneration can follow the profiles measured in the IMO apparatus tests. The inputs for this

method include the heat release rate profile, or temperature profile for the smoldering sources,

and the smoke release rate profile. The mixture fraction model in FDS was used initially; thiscombustion model uses the heat release rate, smoke yield, and heat of combustion as inputs.

This method is based on a constant correlation between heat release rate and smoke release rate.

The exhaust velocity and room temperature are also used as initial inputs. The mixture fraction

model does not allow for an accurate recreation of the phenomena involved with incipient firesources due to the varying nature of the initial smoke production relative to the heat release rate.

2.0 Fuel Source CharacterizationThe heat and smoke release rates of eight fuel sources are characterized through fire tests

performed in the IMO intermediate-scale calorimeter located in the UL small-scale fire testlaboratory in Northbrook, IL. The eight fuel sources are identified in Table 1; they include

shredded office paper, polyurethane foam wrapped in micro-fiber fabric (used as a flaming and

smoldering source), printed circuit board, computer case ABS plastic, ponderosa pine, cotton

linen fabric, and PVC insulated wire.

The IMO apparatus consists of a square hood with a noncombustible skirt and an exhaust ductmeasuring .1778 m (7 in.) in diameter, as illustrated schematically in Figure 1. The fuel sources

are burned beneath the hood and the combustion products are exhausted through and measured in

the exhaust duct Smoke obscuration is also measured in the exhaust duct


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Because of the sampling time and purging requirements between purges, measurements are taken

at 67 second intervals.

Figure 1. Schematic diagram of the IMO intermediate-scale calorimeter apparatus.


28/148


oxygen levels. This provides reliable linearity and allows parameterization of small measuring

ranges of 0 to 0.5%. The detection limit is 50 ppm.

The load cell is placed in the center of the hood and various platforms have been fabricated tosupport the range of fuel sources being tested. The capacity of this load cell is 2.8 kg with an

accuracy of 1 g.

The hotplate used for the smoldering tests is a Wenesco Model HP1212YX hotplate with a 30.4

by 30.4 by 1.3 cm thick stainless steel surface used along with a CAL95B11PA000programmable thermostat from Cal Controls. This hotplate has a 240 V, 6480 W power supply,

capable of producing temperatures up to 815 C. The UL 217 hotplate temperature ramp is

programmed into this controller and monitored by a thermocouple imbedded in the hotplate.

The Sorensen DCS 60-50 power supply is used only for the PVC insulated wire test. Thisinstrument is capable of providing a range of power from 0 to 60 volts and 0 to 50 amps. It can

also be programmed to maintain a continuous current by varying the amperage to compensate for

changing resistance, which is required for the PVC insulated wire test protocol.

In addition to the fuel and smoke instrumentation, thermocouples are placed within the exhaust

duct and in the ambient room. A bidirectional probe is also placed in the exhaust duct for

velocity measurements.

The thermocouple in the exhaust duct is used to measure the exhaust gas temperatures near the

smoke eye. The thermocouple in the room is used to measure the initial air temperature to

provide a baseline starting ambient temperature for FDS5 input.

The bidirectional probe in the exhaust duct is connected to a Baratron Model 220CD pressuretransducer with a range of 1 torr. This instrument is placed in the center of the duct to obtain the

maximum velocity by converting the pressure differential. This velocity measurement is used to

ensure that the exhaust flow in the model is similar to the exhaust flow produced in the

experimentation.


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Q = Heat release rate (kW)

C = Calibration constant (0.91)

2OH = Air heat of combustion (13,100 kJ/kgO2)

2OMW = Molecular weight of oxygen (32 g/mol)

airMW = Molecular weight of air (29 g/mol)

em = Mass flow rate in exhaust duct (kg/s)

oOX ,2 = Ambient oxygen mole fraction (0.2095)

2OX = Oxygen mole fraction in exhaust stream

E = Chemical expansion factor (1.105)

expX = Stoichiometric expansion factor (1.5)

Extinction CoefficientThe extinction coefficient is derived from the relationship between the

voltage output from the photocell in the exhaust duct and the light beam intensity. For the

equipment installed for these tests, the relationship is linear.

I

I

lk 0ln

1(2)

where:

k = Extinction coefficient (m-1

)

l = Beam length in exhaust duct (0.1778 m in IMO calorimeter)

0I = Initial clear beam light intensity (mV)

I = Light intensity at time (t) (mV)


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ev = Exhaust velocity in duct at photocell (m/s)

ductA = Cross-sectional area of duct (0.0248 m2

in IMO calorimeter)

Smoke YieldThe accumulating average smoke yield is calculated by dividing the extinctioncross-sectional area by the specific extinction coefficient.

sY (5)

where:

sY = Accumulating average smoke yield (gs/gf)

= Total smoke at time t / Total mass loss at time t (m2/gf)

= 8.7 m2/gs (Specific extinction coefficient)

VelocityA pressure measurement is made in the exhaust duct near the photocell with a

bidirectional probe connected to a pressure transducer. The pressure readings are then convertedto velocity using Eq. 6. There is a correlating coefficient required for this conversion; this factor

is 0.806 for the UL IMO apparatus.

ducte PTv 806.0 (6)

where:

P = Pressure transducer reading (torrs)

ductT = Duct temperature at time (t) (K)


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The ignition source for this test is the burner tube described in TB 604, Test Procedure and

Apparatus for the Flame Resistance of Filled Bedclothing. It consists of a 200 5 mm length of

stainless steel tube with an 8.0 0.1 mm outer diameter and a 6.5 0.1 mm inner diameterconnected to a cylinder containing ultra high purity propane. The stainless steel tube is

connected to a two stage regulator via clear flexible tubing 2.5 to 3.0 m in length and 7.0 1.0mm inner diameter. The flame height for testing is 35 mm when the burner is held horizontally

and allowed to burn freely in air.


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instruments are calibrated, the load cell is zeroed, and all instruments are rechecked. To initiate

the test, all recording instruments are started and the burner is inserted horizontally 25 mm into

the hole near the bottom of the wastebasket for 5 seconds. The burner is then removed and thepaper is allowed to burn until smoke production stops. This procedure is repeated for a total of

three tests.

2.3.2 PU Foam with Micro-fiber Fabric (Flaming)

PU foam with micro-fiber fabric is used to simulate a typical commercial upholstery assembly.

The TB 604 ignition source, the same ignition source used for the shredded office paper tests, isused for this test. This ignition source is similar to a butane cigarette lighter flame.

Two blocks of PU foam measuring 20 by 8 by 10 cm are wrapped in a 50 by 60 cm sheet of

micro-fiber fabric in the manner shown in Figure 3 to create a block of material that measures 20

by 16 by 10 cm. Both materials are conditioned prior to assembly for a minimum of 24 hours at

23 0.5 C and 50 5 % relative humidity. A foil tray is positioned beneath the specimenduring testing to contain the liquefied PU foam. The specimen is placed on the foil tray with the

20 by 16 cm side down, which incorporated the pinned fabric.

Figure 3Photos of PU foam / microfiber fire source assembly.


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Two 7.5 by 7.5 by 1.57 mm printed circuit boards conditioned to 23 0.5 C and 50 5 %relative humidity for a minimum of 24 hours are placed 2 cm apart in a vertical orientation. The

line burner is centered 1.5 cm below the PC board assembly, perpendicular to the PC boards.This setup is shown in Figure 44 and 5. The specimen assembly is elevated 2.5 cm off of the

platform of the load cell to accommodate the location of the line burner. The line burner valley

is 3 cm wide and the valley running parallel to the PC boards is 2.5 cm wide. The specimenassembly is placed such that the PC boards are over the 2.5 cm valley. The requirements for the

line burner are described in section 5 of ATIS T1.319. It is constructed of type 304 stainless

steel tubing with a nominal 9.5 mm diameter and one end welded closed. Eleven holes, 2.78 0.1 mm in diameter, with 13 mm spacing on center are drilled through one side of the tube,

starting 13 mm from the welded end of the tube. Compression fittings are used to connect theburner to the output of the fuel assembly. Ultra high purity methane is used.

Figure 4Photos of PC board fire source assembly.


34/148


mm flame height. All recording instruments are initiated and the flame of the line burner is

allowed to burn for 1 minute to stabilize before the printed circuit boards are placed on top. The

PC boards are placed above the center of the line burner, oriented perpendicular to the line burner.The line burner remains on for the duration of the test because the PC boards will not sustain a

flame without an external heat source. The tests are run until smoke production from the printed

circuit boards stops. This procedure is shown in Figure 6. Three tests are conducted to evaluatetest repeatability.

Figure 6Photos of PC board fire source assembly during testing.

2.3.4 Computer Case ABS Plastic

The computer case material is representative of the materials used as external casing for

electronics equipment. The 50 W ignition source specified in UL 94 is used and the specimen

setup is also similar to that specified in UL 94.

The specimen is 125 mm tall by 13 mm wide by 3.5 mm thick and is conditioned for a minimum

of 24 hours at 23 0.5 C and 50 5 % relative humidity. The specimen is wrapped in a 6 by 15


35/148


down slightly to maintain the 1 cm distance to prevent the material from getting into the burner

tube. Three tests are operated for 5 minutes until smoke production stops.

Figure 7Photos of computer case fire source assemblies.

2.3.5 PU Foam with Micro-fiber Fabric (Smoldering)

The smoldering test for the polyurethane foam with micro-fiber fabric uses the UL 217

smoldering smoke test temperature profile and the Wenesco HP1212YX hotplate. The materialis placed in a 22.8 by 22.8 cm steel pan lined with foil and then placed on the heated surface of

the hotplate.

Two blocks of PU foam measuring 20 by 8 by 10 cm are wrapped in a 50 by 60 cm sheet of

micro-fiber fabric in the manner shown in Figure 8 to create a block of material that measured 20


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Figure 8Photos of smoldering PU foam fire source assembly.

Table 3Hotplate Temperature (UL 217)


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Ten ponderosa pine sticks, free from knots and pitches, are placed in a spoke pattern on the

hotplate so that the sticks are 36 degrees apart. The sticks are 7.6 by 2.5 by 1.9 cm with the 1.9

by 7.6 cm side in contact with the hotplate. Each stick is conditioned for a minimum of 48 hoursat 52C (125F) in an air-circulating oven. The hotplate, controller, and stick positioning are

shown in Figure 10.

Figure 10Photos of Ponderosa pine stick fire source assembly.

The hotplate surface is approximately level with the bottom of the hood curtain to ensure that the

low buoyancy smoke produced from this smoldering source is completely collected by the

exhaust duct. The test is initiated by placing the ponderosa pine sticks on the hotplate in thespecified spoke pattern, activating all recording instruments, and switching on the

preprogrammed proportioning temperature controller. This test is performed in triplicate for

6300 seconds with pre-test and post-test weights taken for each test. The sticks lose most of theiroriginal mass and much of what is left is only char.

2.3.7 Cotton Linen Fabric


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Figure 11Photos of cotton linen fabric fire source assembly.

The hotplate surface is approximately level with the bottom of the hood curtain to ensure that the

low buoyancy smoke produced from this smoldering source is completely collected by the

exhaust duct. To begin this test, the two sheets of fabric are stacked and adjusted so that the

edges and corners match up. They are then placed on the hotplate, pressed flat and smoothed outacross the heated surface. All recording instruments are started and the proportioning

temperature controller is switched on to the preprogrammed temperature profile. The test is

performed in triplicate for a minimum duration of 90 minutes, which allowed for totalconsumption of the cotton sheets. Prior to testing, each set of sheets is weighed and post-test

weight is assumed to be zero.

2.3.8 PVC Insulated Wire

The PVC insulated wire test is representative of smoke produced from an electrical overload.

This test generally follows the procedures detailed in NFPA 76 Appendix B, Performance TestProcedures for Very Early Warning and Early Warning Fire Detection Systems. The smoke

produced from this test simulates the smoke that might be produced during the early stages of a

telecommunications fire


39/148


Figure 22Photos of PVC insulated wire fire source assembly.

3.0 Experimental Results

The experimental results described in this chapter are produced from fire tests performed

following the procedures explained in Section 2. These tests were completed during the summerof 2007 with assistance and provisions from Underwriters Laboratories, Inc., in Northbrook,

Illinois. The data provided in this section consist of mass loss (for flaming sources only), heat

release rate (for flaming sources only), smoke release rate, smoke yield, smoke concentration,

smoke particle diameter, carbon monoxide, and carbon dioxide.

3.1 Shredded Office Paper

The shredded office paper tests are performed for 360 seconds, which allowed for enough time

for the smoke generation to reach its peak and return back to zero. The variations between thetests as well as the trends produced from this experiment are presented in Figures 13-19.


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0

10

20

30

40

50

60

70

0 60 120 180 240 300 360

Time (s)

Ma

ssLoss(g)

Test 1 Test 2 Test 3

Figure 33Shredded office paper mass loss.

10

12

14


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0

0.5

1

1.5

2

2.5

0 60 120 180 240 300 360Time (s)

SR

R(m^2/s)


Figure 55Shredded office paper smoke release rate.

7 0E+06

8.0E+06

9.0E+06

1.0E+07

1/cc)


42/148


0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

0.50

0 60 120 180 240 300 360

Time (s)

MeanD

iameter(micron)


Figure 77Shredded office paper mean particle diameter.

700

800

900


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0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

0 60 120 180 240 300 360Time (s)

C

O2(ppm)


Figure 99Shredded office paper carbon dioxide output.

3.2 PU Foam with Micro-fiber Fabric (Flaming)

The PU foam with micro-fiber fabric package flaming test is performed for 640 seconds to allowfor complete smoke production. This test shows unique characteristics and produces consistent

data as shown in Figures 20-26.


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0

10

20

30

40

50

60

70

80

90

100

110

0 60 120 180 240 300 360 420 480 540 600Time (s)

Ma

ssLoss(g)


Figure 2010Flaming PU foam with micro-fiber fabric mass loss.

10

12


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0

0.1

0.2

0.3

0.4

0.5

0.6

0 60 120 180 240 300 360 420 480 540 600Time (s)

SRR(m^2/s)


Figure 22Flaming PU foam with micro-fiber fabric smoke release rate.

3.5E+06

4.0E+06

4.5E+06

/cc)


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0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0 60 120 180 240 300 360 420 480 540 600

Time (s)

MeanD

iameter(micron)


Figure 24Flaming PU foam with micro-fiber fabric mean particle diameter.

200

250


47/148


0

1000

2000

3000

4000

5000

6000

7000

0 60 120 180 240 300 360 420 480 540 600Time (s)

C

O2(ppm)


Figure 26Flaming PU foam with micro-fiber fabric carbon dioxide output.

3.3 Printed Circuit Board

The printed circuit board test is performed for 540 seconds to allow for the material to besignificantly affected by the burner. The PC boards intumesce and will not sustain ignition

without an external heat source. The data from the experiments with the printed circuit board are

presented in Figures 27-33 The data includes the contributions of the line burner


48/148


0

2

4

6

8

10

12

14

0 60 120 180 240 300 360 420 480 540Time (s)

Ma

ssLoss(g)


Figure 27Printed circuit board mass loss.

2.5

3


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0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0 60 120 180 240 300 360 420 480 540Time (s)

SR

R(m^2/s)


Figure 29Printed circuit board smoke release rate.

8.0E+06

9.0E+06

1.0E+07

c)


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0.00

0.05

0.10

0.15

0.20

0.25

0 60 120 180 240 300 360 420 480 540

Time (s)

MeanD

iameter(micron)


Figure 31Printed circuit board mean particle diameter.

300

350

400


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0

200

400

600

800

1000

1200

0 60 120 180 240 300 360 420 480 540

Time (s)

CO2(ppm)


Figure 33Printed circuit board carbon dioxide output.

3.4 Computer Case ABS Plastic

The computer case ABS plastic test is performed for 340 seconds to allow for complete smoke

production and affect from the burner. The computer case material deforms significantly duringthe test, which may have caused some of the variations. The data described in Figures 34-40

includes the contributions of the 50 W burner.


52/148


0

0.5

1

1.5

2

2.5

3

0 60 120 180 240 300

Time (s)

Sam

pleWeight(g)


Figure 34Computer case ABS plastic mass loss.

0.6

0.7

0.8


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0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0 60 120 180 240 300

Time (s)

SRR(m^2/s)


Figure 36Computer case ABS plastic smoke release rate.

2 0E+05

2.5E+05


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0.00

0.05

0.10

0.15

0.20

0.25

0 60 120 180 240 300

Time (s)

Mean

Diameter(micron)


Figure 38Computer case ABS plastic mean particle diameter.

20.0

25.0


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0.0

20.0

40.0

60.0

80.0

100.0

120.0

0 60 120 180 240 300Time (s)

CO2(ppm)


Figure 40Computer case ABS plastic carbon dioxide output.

3.5 PU Foam with Micro-fiber Fabric (Smoldering)

The smoldering PU foam with micro-fiber fabric package test is performed for a minimum of4500 seconds to capture the increase and decay of smoke production. The variations in databetween the tests are indicated in Figures 41-45. During Tests 2 and 3, the FTIR spectrometer

malfunctioned and failed to produce data after approximately 1000 seconds


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0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0 600 1200 1800 2400 3000 3600 4200 4800Time (s)

SRR(m^2/s)


Figure 41Smoldering PU foam w/ micro-fiber fabric smoke release rate.

60000

70000

80000

/cc)


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0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

0 600 1200 1800 2400 3000 3600 4200 4800Time (s)

MeanD

iameter(micron)


Figure 43Smoldering PU foam w/ micro-fiber fabric mean particle diameter.

100

120

140


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0

20

40

60

80

100

120

0 600 1200 1800 2400 3000 3600 4200 4800Time (s)

C

O2(ppm)


Figure 45Smoldering PU foam w/ micro-fiber fabric carbon dioxide output.

3.6 Ponderosa Pine Sticks

The ponderosa pine wood stick test is performed for 6400 seconds to capture the full smokerelease rate curve. This test is based on the UL 217 Smoldering Smoke Test and is very

consistent between data sets. The results of the three tests are presented in Figures 46-50.


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0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0.18

0 600 1200 1800 2400 3000 3600 4200 4800 5400 6000

Time (s)

S

RR(m^2/s)


Figure 46Ponderosa pine smoke release rate.

5000000

6000000

7000000

/cc)


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0.00

0.05

0.10

0.15

0.20

0.25

0.30

0 600 1200 1800 2400 3000 3600 4200 4800 5400 6000

Time (s)

MeanD

iameter(micron)


Figure 48Ponderosa pine mean particle diameter.

250

300


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0

50

100

150

200

250

300

350

0 600 1200 1800 2400 3000 3600 4200 4800 5400 6000

Time (s)

CO2(ppm)


Figure 50Ponderosa pine carbon dioxide output.

3.7 Cotton Linen Fabric

The cotton linen fabric test is performed for 6000 seconds to ensure that the smoke data is

completely characterized. The data presented in Figures 51-55 show the variations andconsistency between the data sets.


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0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0 600 1200 1800 2400 3000 3600 4200 4800 5400 6000

Time (s)

S

RR(m^2/s)


Figure 51Cotton linen fabric smoke release rate.

2500000

3000000

3500000

1/cc)


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0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0 600 1200 1800 2400 3000 3600 4200 4800 5400 6000

Time (s)

MeanD

iameter(micron)


Figure 53Cotton linen fabric mean particle diameter.

250

300


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0

100

200

300

400

500

600

700

800

900

1000

0 600 1200 1800 2400 3000 3600 4200 4800 5400 6000

Time (s)

CO2(ppm)


Figure 55Cotton linen fabric carbon dioxide output.

3.8 PVC Insulated Wire

The PVC insulate wire test is unique to this test set. It does not have an external heat source

provided by a hotplate and does not generate a significant amount of heat itself. Thischaracteristic means that the smoke produced will not be very buoyant. This test is only

performed for 240 seconds because the smoke production is quick. The data from this test series


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0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0.18

0 30 60 90 120 150 180 210 240

Time (s)

S

RR(m^2/s)

Test 1 Test 2 Test 3 Model

Figure 56PVC insulated wire smoke release rate.

250000

300000

1/cc)


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0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

0 30 60 90 120 150 180 210 240

Time (s)

Mean

Diameter(micron)


Figure 58PVC insulated wire mean particle diameter.

2.0

2.5

f S f


67/148


0

5

10

15

20

25

30

0 30 60 90 120 150 180 210 240

Time (s)

CO2(ppm)


Figure 60PVC insulated wire carbon dioxide output.

4.0 Analysis of Experiments

In this section, the results of the tests in the IMO apparatus are analyzed and discussed for theeight incipient fire sources.

V lid ti f S k D t ti P f P di ti M th d l V l 1


68/148


Figure 11Photos of shredded office paper test.

The mass loss from the shredded office paper tests is similar in rate, but differs in time again due

to the inconsistent packing density. Most of the mass is consumed during these tests and theremaining mass consists of char, a few remaining strands, and water residue produced from the

combustion. For each of the tests, most mass consumption occurs between approximately 30

seconds and 120 seconds as shown inFigure 313. In the initial part of this graph, the materialdoes not begin to significantly burn until approximately 10 seconds after ignition. This time

interval includes the 5 second ignition source application to the base of the material. The smoke

release rates produced from these tests shows the effect of the packing density as well.

The smoke release rate data is consistent in nature with the heat release rate and the mass lossdata. In all tests, the smoke release rate peaks just before the heat release rate. This is consistent

with the observations during testing. The material initially smolders and produces a significant

amount of smoke without a high heat release rate followed by flame-through where smoke



69/148


The mean particle diameters range from 0.10 microns to 0.45 microns over the course of the test.

Larger particles can be attributed to the smoldering phase of this test. Figure 717displays this

data. In Test 2, again, the mean particle diameter peaks more than 60 seconds later than theother two tests.

The gas effluent data focuses on carbon monoxide and carbon dioxide. The carbon monoxide

production from these tests is high due to the initial smoldering and the peaks correspond to the

heat release rate and smoke release rate peaks. Figure 8shows that test one and two are similarin production rates, only skewed by time. Carbon monoxide production reached as high as

almost 800 ppm for test 3. The carbon dioxide production is also high for test 3; whereas, test 1

and test 2 were similar in production peaks. Carbon dioxide concentration reached nearly 9500

ppm. This is shown inFigure 9.

4.2 PU Foam with Micro-fiber Fabric (Flaming)

The flaming PU foam with micro-fiber fabric test produced results which were appreciably

different than those from other materials due to the thermal response of the polyurethane foam.

In general, the data from the tests with this sample were consistent and the tests were repeatable.

Figure 201020 shows the mass loss data produced from these tests. The tests are almost identicaluntil approximately 180 seconds where the material begins to melt away from the ignited areas

and the mass loss rate becomes slower. This transition to a liquid pool fire is unique to this

material as compared to the rest of the fuel sources and is shown in Figure 1262. The fuelpackage loses approximately 80 % of its mass during the tests and the remaining material

consists of sticky clumps of char and residue from the PU foam. The remains of the fuel

package are shown in Figure 1363. The initial spike in the mass loss data shown in Figure

201020 is due to the TB 604 igniter coming in contact with the load cell. The igniter is appliedfor 20 seconds.



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Figure 133Remains of PU foam fuel package near end of test.

The heat release rate curves produced from these tests show similar traits. Two distinct peaksare evident in Figure 21 for each test. The first peak is reached when the flames begin to moveacross the solid fuel package, igniting a significant portion of the material. The heat release rate

th b i t d th h t t t f th i it d ti b i t lt th i i

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seconds. The PU foam with micro-fiber fabric produces an average smoke yield of 0.0952

gs/gconsumed.

The particle count density is similar between the tests. This is shown inFigure 23. Test 3 showsa higher peak density but follows a similar profile to tests 1 and 2. Tests 1 and 2 are similar

throughout the duration of the procedure. Particle count densities begin to increase at

approximately 50 seconds and do not return to zero until approximately 580 seconds, which is

almost 100 seconds after the smoke production stops. This lag can be associated with the timerequired to clear the measurement chamber within the WPS spectrometer.

Mean particle diameter, shown in Figure 24, is consistent between the three tests. The peak

diameter of 0.30 microns is reached at approximately 320 seconds. Near the end of the test, themean diameter begins to increase again; this can also be associated with the clearing time of themeasurement chamber of the WPS spectrometer.

Carbon monoxide and carbon dioxide profiles, shown in Figure 25 and Figure 26, are similar to

the heat release and smoke release rate curves. The carbon monoxide production reaches slightly

higher values during the solid fuel dominated combustion phase due to incomplete combustionas the flame propagates across the material. Once the material is melted and preheated, more

efficient combustion occurs. The carbon dioxide shows the same peak relationship. Test 1

shows a significant decrease in carbon dioxide production during the transition to liquid fuel

dominated combustion.

4.3 Printed Circuit Board

The printed circuit board tests show consistent values between the tests. This material showed

significant reactions during the beginning of the tests and only minor changes near the end.

The heat release rate curves produced from this test include the contributions of the line burner.

The heat release rate from this ignition source is approximately 1.3 kW. Figure 28 shows thatthe PC boards create a peak in the heat release rate just before 60 seconds and then provide a

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Figure 64PC boards during testing. Note the charred bulges from the center of the

boards.

The mass loss data from these tests is shown in Figure 27. The mass loss is consistent betweenthe tests and shows that the fuel consumption rate is highest from approximately 20 seconds to

90 seconds. The average mass loss percentage from the PC boards is 15.5%. The large spikes at



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peak smoke release rate, heat release rate, and mass loss rate. The mean particle diameter then

gradually decays for the remaining duration of the test.

The carbon monoxide and carbon dioxide production from the printed circuit boards indicated inFigure 32 and

Figure33 exhibits peaks at similar times as for the heat and smoke release rate data. The carbon

monoxide data is very consistent, with each test peaking just before 60 seconds, followed by a

rapid decay. Carbon dioxide also peaks near 60 seconds with some variations in output for theremaining duration of the test.

4.4 Computer Case ABS Plastic

The computer case ABS plastic test results in some data that is below the accuracy of the

instrumentation. Some instruments would not register any changes and therefore, some data may

seem to be missing from the graphs included in Section 3.4.

The mass loss from these tests ranged from approximately 1.4 grams to 2.6 grams. This equatesto an average mass loss percentage of approximately 18.2 %. All mass loss profiles in Figure

become constant after approximately 130 seconds, indicative of the mass loss stopping at thispoint.

The heat release rate curves in Figure show that the heat output including the contribution of the50 W burner is below the accuracy of the IMO intermediate-scale calorimeter. Test 1 does not

produce data, test 2 and 3 show that the heat release rate is nearly constant at just below 0.4 kW

until 180 seconds where test 3 drops to below 0.1 kW.

The smoke release rate data provided in Figure 36shows that tests 2 and 3 are consistent and test

1 produced less smoke. This is consistent with the mass loss trends. Less smoke is produced inTest 1 and lost the least amount of mass because the material began to drip during testing,

requiring that the burn be moved to avoid contaminating the burner tube or extinguishing the

fl Th k d i f h ABS l i b i Fi



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Figure 65Computer case ABS plastic smoke production.

4.5 PU Foam with Micro-fiber Fabric (Smoldering)

The smoldering test for the PU foam with micro-fiber fabric produced consistent data. As

illustrated in Figure 41, the smoke release rate from these tests does not become significant

smoke generation until approximately 2300 seconds. At this point, the smoke release ratecontinues to rise and peaks at approximately 3700 to 3800 seconds. The smoke release rate islow compared to the flaming tests, but total smoke generation is significantly higher. Test 3 is



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approximately 3700 seconds, near the peak of the smoke release rate. At this point, it begins to

decrease. The carbon dioxide production is erratic and shows no trend. The data for test 1 in

Figure 45 may also be affected by instrument malfunction.

4.6 Ponderosa Pine Sticks

The ponderosa pine tests are consistent and show similar trends between tests. Test 1 shows

slightly higher values for some of the data, but remains similar.

The smoke release rate of smoldering ponderosa pine begins much earlier than the PU foam

package. Figure 46shows that the smoke release rate begins to increase near 500 seconds. Thiscurve peaks near 4000 seconds and then falls dramatically to a point where it plateaus for a bit

and then continues to decrease. This trend can be seen in each of the data sets in Figure 46. The

total smoke produced during this test is approximately 79 m2.

The particle count density is shown in Figure 47 and shows that particle production lags

significantly behind smoke release. For each test, the particle count density does not becomesignificant until after 3000 seconds. Test 1 shows values that are nearly twice those produced in

tests 2 and 3. Variations may be due to several factors, but its appears that they are primarily

due to the characteristics of the pine sticks that are chosen for the test. The density of the woodvaries significantly between sticks. For these tests, each stick is required to be within 2 grams of

16 grams to avoid large variations.

Figure 48displays the mean particle diameters produced during the smoldering ponderosa pine

tests. Each data set shows the same pattern with minor variations. This graph shows that eventhough smoke production is non existent, particles are still being produced, though not at a

significant rate. These particles are noticed during testing by the smell of the wood as it begins

to deteriorate and produce aromatics.The carbon monoxide and carbon dioxide data are shown in Figure 49 and Figure 50,respectively The carbon monoxide data is very consistent and peaks over 1000 seconds after the



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the hotplate temperature continues to rise, the lower sheet becomes significantly charred and the

upper sheet begins to decompose under the higher heat. Near 5000 seconds, the upper sheet

rapidly smolders, creating the peak that is seen in this graph. The material is eventuallycompletely consumed and small piles of char remain. The shriveled upper sheet and the post-test

remains can be seen in Figure 66. Figure 67 shows the mid-test decomposition of the lower

sheet as compared to the upper sheet. The lower sheet is significantly more decomposed and isalmost completely consumed by the time the upper sheet begins to rapidly decompose.

Figure 66Cotton linen fabric upper sheet shriveled (left). Note the darker valleys where

it remains in contact with the hotplate. Post-test remains (right).



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for test 3 is not available due to an instrument malfunction. Tests 1 and 2 show similar profiles

throughout the test with peaks that agree with the smoke release rate.

The mean particle diameter data does not change significantly, nor are the values verydistinguishable from the ambient data. There are some peaks in test 1 and test 3 near 3300

seconds and 5100 seconds, but test 2 does not show any change. Figure 53 displays these results.

The carbon monoxide graph, Figure 54, shows that CO concentrations begin to develop at

approximately 1300 seconds and continue to increase steadily until 5000 seconds. The primarypeak from the smoke release rate data can be seen near 2500 seconds, but the carbon monoxide

concentration begins to increase dramatically near 5000 seconds as the smoke release rate

increases. The carbon dioxide production, Figure 55, of this test is very low. This is due to thefiltering effects of the upper sheet and the smoldering nature of the test.

4.8 PVC Insulated Wire

The PVC insulated wire test is unique to the smoldering tests in that it is of short duration andhas no significant heat source.

The smoke release rate data is provided inFigure 56. Smoke generation does not begin untilafter 60 seconds. At this point it rapidly increases, creating a peak in the smoke release rate data

that is consistent in time and duration for the tests. The magnitude of smoke release rate issignificantly higher in test 2 and test 1 is the lowest. Smoke production occurs for approximately

100 seconds. The buoyancy characteristics of the smoke are very low. The movement is laminar

and slow. This is shown in Figure 68.



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Documents

FPRF Final Report Volume 1