Flame Propagation Precision Analysis Per ASTM E 691

Flame Propagation Precision Analysis Per ASTM E 691 Round Robin #7 Polyimide Film – Metallized Tedlartm Tape Varying Heat Flux Monroe Shumate 3/05

ASTM E 691 Precision Analysis Practice for conducting an inter-laboratory test program to determine precision of a test method Practice has been in use for over 25 years

Purpose of an Inter-laboratory Study • Primary – Provide information to prepare precision statement on test method • Secondary- Provide suggestions where to look for improvements to test method

What is precision ? Goal Good Accuracy Good Precision Poor Accuracy Good Precision Good Accuracy Poor Precision Poor Accuracy Poor Precision

So what’s measured and reported? • • • Xbar - Cell Average SX - Standard Deviation (Stdev) cell averages Sr – Repeatability Stdev with-in lab variation SR- Reproducibility Stdev between lab variation r - Repeatability limit (95% confidence = 2. 8*Sr) R – Reproducibility limit (95% confidence = 2. 8*SR)

What does this data show? • • X bar shows average value for this sample/test Sx shows how much the values will vary Sr shows within lab variation as compared to other labs SR shows between lab variation • r - Within lab max. variation or noise – should be 1/4 of the spec limit • R – Between labs max. variation or noise – should be 1/4 of the spec limit

Test Data Round Robin 7 Sample Description & Test Setup • • Polyimide Facing Metallized Tedlar Tape Fiber Glass AA class – 0. 34 pcf Test at 3 heat flux settings

Lab Participation • 10 Labs • 5 samples/lab

Equipment & Setup • Electric and Gas Radiant panels • Set up according to FAR Standard with exception to heat flux • Set up performed by each lab

Reporting Results • Record heat flux, room temperature, relative humidity, controller temperature settings • Report – Flame Propagation – After Flame

ASTM Analysis • Input raw data from round robin • Determine average, deviation, and standard deviation for the following: – For each lab – For all labs combined – Compare individual labs to all labs

Initial Test Results One Set of Raw Data is s y l na a n o isi c e r p m r o f er p s t e ta l da s i th g sin U a b c d g h i j

Initial test results One set of data Results heat flux setting 1. 0 Btu/Sqft Sec. After Flame X bar Sx S r SR r R 2. 1 3. 4 7. 6 17. 6 21. 2 21. 3 Spec Limit – 3 sec max. t s e h So o d w o H k? o o l s i

Initial test results One set of data Results heat flux setting 1. 0 Btu/Sqft Sec. After Flame X bar Sx S r SR r R 2. 1 3. 4 7. 6 17. 6 21. 2 21. 3 ? k o ) e g a r e Spec Limit – 3 sec max. v A ( r Is a b X

Initial test results One set of data Results heat flux setting 1. 0 Btu/Sqft Sec. After Flame X bar Sx S r SR r R 2. 1 3. 4 7. 6 17. 6 21. 2 21. 3 u o y on? n e ati h r w vari a b or X s Sx i w r Ho side n co Spec Limit – 3 sec max.

Initial test results One set of data Results heat flux setting 1. 0 Btu/Sqft Sec. After Flame X bar Sx S r SR r R 2. 1 3. 4 7. 6 17. 6 21. 2 21. 3 es o d w o h Spec Limit – 3 sec max. n o i ? t R ? s t i r e o m i qu o r l e c t t e a e p s im par t l e h u om t e f o th it c r ¼ o lim f R w Is No spec the

Precision analysis – All data Heat flux settings Btu/sqft sec X bar Sx S r SR r R After Flame (spec 3 sec. ) 1 2. 1 3. 4 7. 6 21. 2 21. 3 9. 0 3. 0 8. 4 12. 5 23. 5 35. 1 1. 5 13. 2 10. 3 14. 6 16. 6 40. 9 46. 6 Flame Propagation (spec 2”) 1 1. 4 0. 9 1. 3 1. 5 3. 6 4. 1 1. 3 3. 8 3. 0 2. 3 3. 7 6. 6 10. 3 1. 5 4. 4 3. 3 2. 6 4. 1 7. 4 11. 4 Remember R should be ¼ of spec

Conclusion • Test method is not precise for the type of sample tested (Need to analyze other types of samples) • Both within and between lab variation needs to be addressed – this points to both the equipment and operator

Recommendation • Continue FAA lab inspection process to refine equipment setups for each lab – then repeat round robin • Conduct precision analysis for other types of samples • Conduct FMEA – failure mode effect analysis – to list & prioritize possible areas for evaluation and improvement • Use data from FMEA to conduct ruggedness test (ASTM E 1169) or DOE Optimize equipment/operator specs Monroe Shumate 3/05