EXTERNAL OVERVIEW COMMENTARY – PREPARED FEBRUARY 2008
TO: Australian Fibreglass Insulation Industry
In 1975 you recommended to government** home ceiling insulation - fibreglass thickness levels of:
“100mm for Canberra, 75mm for Sydney Melbourne Hobart,
50mm for Adelaide”
NB: 1975 R-value equivalents 100mm=R2.0, 75mm=R1.5, 50mm=R1.0
SO HOW DO YOU JUSTIFY YOUR
CONTRADICTORY PRESENT DAY RECOMMENDATION OF R5 (210mm) & R6 (260mm) BATTS ?
**Mineral
Wool Manufacturers’ Association of
“Mandatory Domestic
Insulation-Potential Energy Savings” see keys pages 10,63,72 .
Report focus: only with heat
flow through ceilings under winter conditions.
THE FOLLOWING INDEPENDENT
TECHNICAL PAPERS REFUTE THIS RECOMMENDATION:
THE LAW OF DIMINISHING RETURNS *increasing R-value over R2.5 is of little
benefit
Refer to CSIRO quotes: http://www.concertinafoilbatts.com/FOIL%20BATT%20FACTS-8.pdf
The Diminishing
Benefit Of Extra Home Insulation, J.Fricker - 18 April 2002.
The
Effect Of Thermal Bridging At Higher R Values, J.Fricker - January, 2003.
***click direct web links
AS2627.1(1993) “RECOMMENDED LEVELS OF INSULATION”- IN
CEILINGS AND WALLS
Formally withdrawn January 2007, and can
no longer be referenced by the building industry or
any energy efficiency regulations or
advice bodies.
This Standard(1983 & 1993 versions)
was originally funded by the fibreglass industry.
Explanation for the withdrawl: http://www.concertinafoilbatts.com/FOIL_BATT_FACTS-9.pdf
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ANY SUGGESTION THAT SINCE 1975, DRAMATICALLY
INCREASED R-VALUE LEVELS IN CEILINGS CAN BE JUSTIFIED, BECAUSE OF THE CURRENT
DAY WIDESPREAD USE OF REFRIGERATIVE AIRCONDITIONING, IS NOT CORRECT.
WHY? BECAUSE BULK INSULATIONS, REGARDLESS
OF THICKNESS, ARE
NOT TESTED FOR HIGH TEMPERATURE RADIATION EFFECTS,
WHICH IS ONE OF THE TESTING PROTOCOLS LISTED IN THE INSULATION STANDARD
AS/NZ4859.1(2002)
BUT NOT ENFORCED.
BULK INSULATIONS ARE PERMITTED TO REVEAL R-VALUES
MEASURED AT
“STEADY STATE” AT A MAXIMUM
TEMPERATURE OF 33degC CONDUCTED HEAT -
NOT TYPICAL ROOF SPACE RADIANT HEAT EFFECTS
OF 60-70degc.
FURTHER REFERENCES: http://www.concertinafoilbatts.com/foilfacts.htm
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CLICK HERE to view Mineral Wool Association Submission to Government (PDF) |