29th October 2012
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#1 | | Lives for gear
Joined: May 2012
Posts: 1,337
Thread Starter | 703 confusion
I have searched the forums and saw a few different GFR numbers for 703. What is a optimal value for calculations?
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30th October 2012
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#2 | | Gear addict
Joined: Sep 2012 Location: Atlanta, GA & Bradford, UK
Posts: 358
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It depends on who you trust. Owens Corning themselves say 16k, NASA says 27k. Perhaps if you're not sure you could meet in the middle?
I use 27k for calculations.
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30th October 2012
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#3 | | Lives for gear
Joined: May 2012
Posts: 1,337
Thread Starter |
I have been using 22k but 16-27 makes a huge difference.
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30th October 2012
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#4 | | Lives for gear
Joined: May 2004 Location: Hamilton, On Canada
Posts: 4,483
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the value that I trust is 15,000 rayls. The NASA data is from many years ago and formulations over the years.
Andre
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30th October 2012
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#5 | | Gear addict
Joined: Sep 2012 Location: Atlanta, GA & Bradford, UK
Posts: 358
| Quote:
Originally Posted by avare  the value that I trust is 15,000 rayls. The NASA data is from many years ago and formulations over the years.
Andre | 15k or 16k?
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30th October 2012
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#6 | | Lives for gear
Joined: May 2012
Posts: 1,337
Thread Starter | Quote:
Originally Posted by avare the value that I trust is 15,000 rayls. The NASA data is from many years ago and formulations over the years.
Andre | Hard to believe government funds could be wrong, but I will take the word of someone with experience!
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30th October 2012
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#7 | | Lives for gear
Joined: May 2004 Location: Hamilton, On Canada
Posts: 4,483
| Quote:
Originally Posted by GIK Acoustics 15k or 16k? | It varies with the phase of the moon. The calculations are fairly robust. For what it is worth, the most modern measured value I am aware of is 19,100 for 47.2 kg/m3 glass wool, used by Komatsu.
Andre
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30th October 2012
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#9 | | Lives for gear
Joined: Apr 2009 Location: State of Insomnia, sleepless USA
Posts: 2,220
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They have probably changed/refined their manufacturing process over the decades; which would probably account for all the various GFR numbers.
Question would be: What is the current products' GFR? We know what it was in 1974 and 1985...
Does anyone know the method of testing this? i have some 2" 703 currently not being used.. would i need special equipment?
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31st October 2012
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#10 | | Lives for gear
Joined: May 2012
Posts: 1,337
Thread Starter | Quote:
Originally Posted by AwwDeOhh They have probably changed/refined their manufacturing process over the decades; which would probably account for all the various GFR numbers.
Question would be: What is the current products' GFR? We know what it was in 1974 and 1985...
Does anyone know the method of testing this? i have some 2" 703 currently not being used.. would i need special equipment? | Do a google, I read about it once. It seemed rather difficult because of all the specialized equipment. If I remember correctly, it looks like an impedance tube, but with an in/out airflow for air current, and the slew rate or something is measured using two pressure sensors.
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31st October 2012
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#11 | | Lives for gear
Joined: May 2004 Location: Hamilton, On Canada
Posts: 4,483
| Quote:
Originally Posted by AwwDeOhh Question would be: What is the current products' GFR? We know what it was in 1974 and 1985... | Komatsu's paper was written in 2006.
Currently,
Andre
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31st October 2012
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#12 | | Lives for gear
Joined: Apr 2009 Location: State of Insomnia, sleepless USA
Posts: 2,220
| Quote:
Originally Posted by avare Komatsu's paper was written in 2006.
Currently,
Andre | Thanks. Good to know.
THough, [hearsay] i've heard they have once again changed their product to all 'ecose' type stuff. I don't know what bearing that would have on it (or if the rumor is true)
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