1 / 30

Finalizing Environmental Test Parameters for Extinguishing Agent Storage Temperature

This presentation discusses the final decision on the storage temperature for extinguishing agents, based on flammability behavior and distribution challenges. It also addresses the uncertainties in gas analysis technology.

ggooch
Download Presentation

Finalizing Environmental Test Parameters for Extinguishing Agent Storage Temperature

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. International Aircraft Systems Fire Protection Working Group Phoenix, AZ, USA 26-27March 2003 Federal Aviation Administration WJ Hughes Technical Center, Fire Safety Section, AAR-440 Atlantic City Int'l Airport, NJ 08405 USA Engine Nacelle Halon Replacement,FAA, WJ Hughes Technical Center Point of Contact : Doug Ingerson Department of Transportation Federal Aviation Administration WJ Hughes Technical Center Fire Safety Branch, AAR-440 Bldg 205 Atlantic City Int'l Airport, NJ 08405 USA tel: 609-485-4945 fax: 609-485-7074 or 609-646-5229 email: Douglas.A.Ingerson@faa.gov web page: http://www.fire.tc.faa.gov/

  2. International Aircraft Systems Fire Protection Working Group Phoenix, AZ, USA 26-27March 2003 Federal Aviation Administration WJ Hughes Technical Center, Fire Safety Section, AAR-440 Atlantic City Int'l Airport, NJ 08405 USA Major Topics for Review Overview of Work, October ’02 – March ’03 • Finalizing Environmental Test Parameters • Quantifying Halon Replacement • Evaluating Pool Fire Behavior • Finding Certification Distribution Near Term Plans • Complete Certification Distribution Work • Complete Pool Fire Evaluation • Evaluate Varied Agent Discharge Impact on Reignition Time Delay • Equivalence Testing

  3. SLIDE# 3 International Aircraft Systems Fire Protection Working Group Phoenix, AZ, USA 26-27March 2003 Federal Aviation Administration WJ Hughes Technical Center, Fire Safety Section, AAR-440 Atlantic City Int'l Airport, NJ 08405 USA FINALIZING ENVIRONMENTAL TEST PARAMETERSExtinguishing agent storage temperature • Referring to the storage temperature of the extinguishing agent during fire testing • Agent storage temperature has been 100°F • Desire expressed for an additional storage temperature of –65°F • FINAL DECISION : Fire testing will be completed at an agent storage temperature of 100°F • Basis for decision • Flammability behavior • Based on a system of fuel, air, and extinguishing agent within a fixed volume having consistent ignition energy (similar to ASTM E-695) • Increasing pressure requires increasing agent concentration to remain nonflammable • Increasing temperature requires increasing agent concentration to remain nonflammable • Given this behavior for comparable combustion behavior • The peak concentration value for a higher temperature will provide adequate protection at lower temperature • The challenge is for the extinguishing agent to DISTRIBUTE and attain the peak value found at the higher temperature while being stored at a lower temperature • This can be demonstrated by non-fire, distribution test alone

  4. SLIDE# 4 Graphic from : Illustrating increasing flammability envelope with increasing temperature 2 International Aircraft Systems Fire Protection Working Group Phoenix, AZ, USA 26-27March 2003 Federal Aviation Administration WJ Hughes Technical Center, Fire Safety Section, AAR-440 Atlantic City Int'l Airport, NJ 08405 USA FINALIZING ENVIRONMENTAL TEST PARAMETERSExtinguishing agent storage temperature

  5. SLIDE# 5 Illustrating increasing flammability envelope with increasing temperature Graphic from : International Aircraft Systems Fire Protection Working Group Phoenix, AZ, USA 26-27March 2003 Federal Aviation Administration WJ Hughes Technical Center, Fire Safety Section, AAR-440 Atlantic City Int'l Airport, NJ 08405 USA FINALIZING ENVIRONMENTAL TEST PARAMETERSExtinguishing agent storage temperature

  6. SLIDE# 6 International Aircraft Systems Fire Protection Working Group Phoenix, AZ, USA 26-27March 2003 Federal Aviation Administration WJ Hughes Technical Center, Fire Safety Section, AAR-440 Atlantic City Int'l Airport, NJ 08405 USA FINALIZING ENVIRONMENTAL TEST PARAMETERSExtinguishing agent storage temperature • Basis for decision (continued) : • Uncertainty due to gas analysis technology • NIST demonstrates possible difficulty with higher boiling point agent (CF3I) at low storage & environmental temperatures • Varying liquid/vapor fractions of extinguishing agent observed during discharge • Room temperature agent & fixture ventilation • Cold temperature agent/room temperature fixture ventilation • Cold temperature agent & fixture ventilation • NIST utilized relatively unobtrusive technology for gas analysis • No sample transport; sample analyzed in test environment during discharge events • Minimal impact on the agent distribution during its measurement • FAA Tech Center utilizing Statham-derivative technology • Gas sample is transported to sensor – sample is heated by transport path • Sensor assembly is a heated environment – sample is heated prior to measurement • Uncertainty at FAA Tech Center : • Gas analysis error - sample transport and measurement will heat and change liquid agent to vapor • The gas analysis error may not permit accurate description of the transport phenomena in the test fixture

  7. SLIDE# 7 International Aircraft Systems Fire Protection Working Group Phoenix, AZ, USA 26-27March 2003 Federal Aviation Administration WJ Hughes Technical Center, Fire Safety Section, AAR-440 Atlantic City Int'l Airport, NJ 08405 USA FINALIZING ENVIRONMENTAL TEST PARAMETERSLower air mass flow rate • Lower air mass flow in the test fixture at the FAA Tech Center is too large • Lower air mass flow has been 1.0 lbm/s • Desire to see 0.2 – 0.4 lbm/s which match flows found in fielded nacelles • FINAL DECISION : Lower air mass flow rate will be 1.0 lbm/s • Basis for decision • Work at FAA Technical Center founded on testing completed at 1.0 lbm/s • Changing to lower mass flow will invalidate database for agent dispersion and fire testing • The test fixture at the FAA Technical center is capable of 0.7 lbm/s minimum • Decreasing ventilation rate typically decreases agent quantity required to meet certification • Lower mass flows move fire protection design towards non-ventilated compartments

  8. SLIDE# 8 International Aircraft Systems Fire Protection Working Group Phoenix, AZ, USA 26-27March 2003 Federal Aviation Administration WJ Hughes Technical Center, Fire Safety Section, AAR-440 Atlantic City Int'l Airport, NJ 08405 USA Quantifying a Halon replacementInitial step – Basis/Process • Reignition time delay is the duration between the extinguishment of the fire and its subsequent reignition • Environmental constraints • Test fixture set up for one macroscopic test scenario • Macroscopic test scenario = one ventilation configuration + one fire scenario • Agent discharged within 1 second • Agent storage temperature of 100°F • A small collection of individually unique tests are performed • Intended to map the behavior of the replacement candidate • A quantity can be estimated as a possible equivalent to the performance of Halon 1301

  9. SLIDE# 9 International Aircraft Systems Fire Protection Working Group Phoenix, AZ, USA 26-27March 2003 Federal Aviation Administration WJ Hughes Technical Center, Fire Safety Section, AAR-440 Atlantic City Int'l Airport, NJ 08405 USA Quantifying a Halon replacementInitial step - Illustration

  10. SLIDE# 10 International Aircraft Systems Fire Protection Working Group Phoenix, AZ, USA 26-27March 2003 Federal Aviation Administration WJ Hughes Technical Center, Fire Safety Section, AAR-440 Atlantic City Int'l Airport, NJ 08405 USA Quantifying a Halon replacementFinal step - Basis • Process requires repeating 5 tests to determine if a quantity is halon equivalent • An unsuccessful quantity can be determined in as few as 2 tests • This process is based on the statistical behavior of past test results • Based on 7 test sequences; each sequence contained 5 replicate tests • Test sequences were varied conditions providing reignition delay results • Evaluated the trend of the reignition time delay over the 5 tests • Evaluation determined whether the sequence of 4 tests would continue to a fifth • This process was successful for 6 of the 7 test sequences

  11. SLIDE# 11 International Aircraft Systems Fire Protection Working Group Phoenix, AZ, USA 26-27March 2003 Federal Aviation Administration WJ Hughes Technical Center, Fire Safety Section, AAR-440 Atlantic City Int'l Airport, NJ 08405 USA Quantifying a Halon replacementFinal step - Process • Process • The average reignition time delay and sample standard deviation for halon are known • Run tests 1 through 4 with the replacement candidate at repeated test condition • Beginning with test #2 • Calculate the running average of the reignition time delay for the replacement candidate • Determine if the running average falls within +/- 1 sample standard deviation (halon) of the halon average reignition time delay • If yes, continue; otherwise change mass and start again

  12. SLIDE# 12 International Aircraft Systems Fire Protection Working Group Phoenix, AZ, USA 26-27March 2003 Federal Aviation Administration WJ Hughes Technical Center, Fire Safety Section, AAR-440 Atlantic City Int'l Airport, NJ 08405 USA Quantifying a Halon replacementFinal step - Process • Process (continued) • Run test #5 and perform the FINAL evaluation • The running average of the reignition time delay (RTD) for the replacement candidate must be equal to or greater than that of halon • The sample standard deviation for the replacement candidate must be less than or equal to that of halon

  13. SLIDE# 13 International Aircraft Systems Fire Protection Working Group Phoenix, AZ, USA 26-27March 2003 Federal Aviation Administration WJ Hughes Technical Center, Fire Safety Section, AAR-440 Atlantic City Int'l Airport, NJ 08405 USA Evaluating Pool Fire BehaviorBackground • Purpose • Observe combustion behavior • Dependent upon a recirculation zone • Recirculation zone forms behind flame stabilizing baffle over the pool of fuel • Determine threat for use in equivalence procedure • Work description • Looked at impact on fire behavior • Varying upstream baffle height • Hot surface behaviors – tube arrays • 2 tube diameters • 2 tube lengths • 2 positions above fuel surface • 2 positions downstream from flame stabilizing baffle • 2 exposed fuel surface areas • Continually operating electrodes • Characterize fire growth • Performed tests without discharging agent

  14. SLIDE# 14 International Aircraft Systems Fire Protection Working Group Phoenix, AZ, USA 26-27March 2003 Federal Aviation Administration WJ Hughes Technical Center, Fire Safety Section, AAR-440 Atlantic City Int'l Airport, NJ 08405 USA Evaluating Pool Fire BehaviorUpstream baffle height • Reviewed literature for experience • Work by Hirst, Farendon, et al. • Indicated 1” baffle height worst case; demonstrated by : • Blow-off velocity • Agent concentration • Ran tests to observe fire behavior related to baffle height • Used baffle heights of 0.50”, 1.50”, & 2” • Exposed fuel surface area of 10.8”x10.8” • Fuel depth of 0.50” • Tube array used to monitor heating ability of fire • 4 straight tubes in a rhombus stack, 24” long x 0.50”OD • Supported 2.25” above fuel surface and 4.25” downstream from baffle • Observations; as baffle height increased : • Tube array temperature increased • Temperatures 16” & 30” downstream decreased • Hottest tube array temperature NOT comparable to profiles observed in hot surface ignition in the spray fire scenario

  15. SLIDE# 15 CORE Exposed fuel surface Flame stabilizing baffle/rib AIRFLOW  STA 527 STA 518 thermocouples UP STA 502 FWD This assembly not present during testing International Aircraft Systems Fire Protection Working Group Phoenix, AZ, USA 26-27March 2003 Federal Aviation Administration WJ Hughes Technical Center, Fire Safety Section, AAR-440 Atlantic City Int'l Airport, NJ 08405 USA Evaluating Pool Fire BehaviorUpstream baffle height - Illustration

  16. SLIDE# 16 International Aircraft Systems Fire Protection Working Group Phoenix, AZ, USA 26-27March 2003 Federal Aviation Administration WJ Hughes Technical Center, Fire Safety Section, AAR-440 Atlantic City Int'l Airport, NJ 08405 USA Evaluating Pool Fire BehaviorHot surface/tube array - Descriptions • Purpose • Further observation of the fire behavior • Determine the surface area of the pool for the final threat in the equivalence process • Determine worst case tube array for evaluation against agent discharge • Altered tube array characteristics • 0.25” & 0.50” diameters • 5” & 10” tube lengths • Tube array supported 0.25” and 1” above fuel surface • Located 2”, 4”, 8”, 12”, & 16” downstream from flame stabilizing baffle • 10.8”x10.8” & 10.8”x20.5” exposed fuel surface areas • Tube array consisted of 3 tubes stacked in an inverted triangular wedge • Thermocouple imbedded in tube array at the middle of the tube length • Fuel depth of 0.50” • Ran multiple tests evaluating the various conditions described

  17. Tube Array End View SLIDE# 17 flame stabilizing rib UP + + + 1/4”OD x 10” tubes AIRFLOW thermocouple 10.8” x 10.8” fuel surface area International Aircraft Systems Fire Protection Working Group Phoenix, AZ, USA 26-27March 2003 Federal Aviation Administration WJ Hughes Technical Center, Fire Safety Section, AAR-440 Atlantic City Int'l Airport, NJ 08405 USA Evaluating Pool Fire BehaviorHot surface/tube array - Illustration AIRFLOW

  18. SLIDE# 18 International Aircraft Systems Fire Protection Working Group Phoenix, AZ, USA 26-27March 2003 Federal Aviation Administration WJ Hughes Technical Center, Fire Safety Section, AAR-440 Atlantic City Int'l Airport, NJ 08405 USA Evaluating Pool Fire BehaviorHot surface/tube array – Observations • Tube array temperatures attaining 1250 – 1325°F • Temperatures consistently hotter when : • Tube diameter was 0.25” • Tube array was downstream 4” or less from baffle • Tube array was supported 1” above fuel surface • Larger fuel surface area produced greatest thermal output • Larger fuel surface had no apparent impact on heating the tube array

  19. SLIDE# 19 International Aircraft Systems Fire Protection Working Group Phoenix, AZ, USA 26-27March 2003 Evaluating Pool Fire BehaviorHot surface/tube array – Tube array temperatures

  20. SLIDE# 20 International Aircraft Systems Fire Protection Working Group Phoenix, AZ, USA 26-27March 2003 Federal Aviation Administration WJ Hughes Technical Center, Fire Safety Section, AAR-440 Atlantic City Int'l Airport, NJ 08405 USA Evaluating Pool Fire BehaviorContinually operating electrodes - Descriptions • Purpose • Further observation of the fire behavior • Determine worst case electrode configuration for evaluation against agent discharge • Conditions for analysis • Electrode gap of 0.13” • Position gap 1.25”, 0.25”, 0.016”, & 0” above fuel surface • Electrode gap placed 0.5”, 2”, 5”, 10”, & 17” downstream from flame stabilizing baffle • Electrode gap placed on fore/aft center line of the pool • 10.8”x20.5” exposed fuel surface area • Fuel depth of 0.50” • No tube array • Marked fuel pan to determine flame propagation behavior • Ran multiple tests evaluating the various conditions described

  21. SLIDE# 21 SLIDE# 21

  22. SLIDE# 22 SLIDE# 22

  23. SLIDE# 23 International Aircraft Systems Fire Protection Working Group Phoenix, AZ, USA 26-27March 2003 Federal Aviation Administration WJ Hughes Technical Center, Fire Safety Section, AAR-440 Atlantic City Int'l Airport, NJ 08405 USA Evaluating Pool Fire BehaviorContinually operating electrodes - Observations • Pool did not ignite unless electrode gap was in contact with fuel surface • Flames propagated across the surface of the pool faster opposing the bulk air flow in the test section • Shortest duration to full pan involvement occurred with mobile electrode gap located 17” downstream from the flame stabilizing baffle

  24. SLIDE# 24 International Aircraft Systems Fire Protection Working Group Phoenix, AZ, USA 26-27March 2003 Federal Aviation Administration WJ Hughes Technical Center, Fire Safety Section, AAR-440 Atlantic City Int'l Airport, NJ 08405 USA Evaluating Pool Fire BehaviorContinually operating electrodes - Observations

  25. SLIDE# 25 International Aircraft Systems Fire Protection Working Group Phoenix, AZ, USA 26-27March 2003 Federal Aviation Administration WJ Hughes Technical Center, Fire Safety Section, AAR-440 Atlantic City Int'l Airport, NJ 08405 USA Evaluating Pool Fire BehaviorContinually operating electrodes - Observations

  26. SLIDE# 26 International Aircraft Systems Fire Protection Working Group Phoenix, AZ, USA 26-27March 2003 Federal Aviation Administration WJ Hughes Technical Center, Fire Safety Section, AAR-440 Atlantic City Int'l Airport, NJ 08405 USA Evaluating Pool Fire BehaviorConclusions • Varied baffle heights • No reason suggested by data that 1” tall baffle is not worst case • Further evaluation required • Tube array • Tubes apparently not hot enough for hot surface ignition based on spray fire results • Worst case tube configuration • Exposed fuel surface of 10.8” x 20.5” length • Three 0.25”OD x 10” long tubes • Tube array located 4” downstream from baffle and supported 1” above fuel • Electrodes • Fastest pan fire developed when electrodes were positioned at the aft end of the pool • Recirculation zone is clearly present • Worst case electrode configuration • Location of 17” downstream from baffle • Electrode gap touched fuel at surface

  27. SLIDE# 27 International Aircraft Systems Fire Protection Working Group Phoenix, AZ, USA 26-27March 2003 Federal Aviation Administration WJ Hughes Technical Center, Fire Safety Section, AAR-440 Atlantic City Int'l Airport, NJ 08405 USA Evaluating Pool Fire BehaviorConclusions (continued) • General comments • Tube array apparently not hot enough for hot surface ignition in any configuration attempted • The hottest tube array was located above the fuel in a region where the electrodes could NOT ignite the pool • Final determination to be made with worst cases tested individually & combined against the discharge of a fire extinguishing agent

  28. SLIDE# 28 International Aircraft Systems Fire Protection Working Group Phoenix, AZ, USA 26-27March 2003 Federal Aviation Administration WJ Hughes Technical Center, Fire Safety Section, AAR-440 Atlantic City Int'l Airport, NJ 08405 USA Agent Distribution SearchBackground • Former Halon quantities producing certification at a storage temperature of –65°F • 5.2 lbf Halon 1301 @ ventilation of 2.2 lbm/s & 100°F • 3.2 lbf Halon 1301 @ ventilation of 1.0 lbm/s & 280°F • These quantities produced excessive concentration profiles since fire testing was occurring at at an agent storage temperature of 100°F • Work occurring to find agent quantities that will produce certification at a storage temperature of 100°F • 5.2 lbf Halon 1301 will be in the 3.5 – 4.0 lbf range • No estimate for reduction from 3.2 lbf Halon 1301

  29. SLIDE# 29 International Aircraft Systems Fire Protection Working Group Phoenix, AZ, USA 26-27March 2003 Federal Aviation Administration WJ Hughes Technical Center, Fire Safety Section, AAR-440 Atlantic City Int'l Airport, NJ 08405 USA 3.90 lbf Halon 1301 @ ventilation of 2.2 lbm/s & 100°F Agent Distribution SearchPreliminary results

  30. SLIDE# 30 International Aircraft Systems Fire Protection Working Group Phoenix, AZ, USA 26-27March 2003 Federal Aviation Administration WJ Hughes Technical Center, Fire Safety Section, AAR-440 Atlantic City Int'l Airport, NJ 08405 USA Near Term Plans • Complete certification distribution work • Finalize work at ventilation rate of 2.2 lbm/s @ 100°F • Accomplish work for the condition of 1.0 lbm/s @ 280°F • Complete pool fire evaluation • Run new quantities of halon against the pool fire • Determine which worst case to use in the equivalence procedure • Evaluate the impact of varied agent storage pressure on reignition time delay • Store the same amount of agent in the same volume at the same temperature • Alter storage pressure • Observe impact on the reignition time delay • Incorporate experience into the equivalence procedure • Equivalence testing

More Related