INDUSTRY NEWS
AFIA is committed to keeping a watchful eye on industry events and through regular industry notices provides members and the general public with information in relation to current issues confronting the Australian building insulation market.
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The most recent notices are listed below:
Dr R. Aynsley Assumptions Audit Review Letter [ Posted Nov 2004 ]
ANTIGLARE
With the recent release of the AFIA dust paper there has also been a great deal of industry discussion in relation to testing reflective aluminium foils for emissivity, in particular where some reflective foil surfaces have applied an antiglare ink. The term “antiglare” used, use to be the code for “lightly-inked foil retaining low IR emittance”. Antiglare ink is generally applied to products that are used as roof sarkings, house wrap vapour barriers or thermo reflective insulation that are all of a continuous roll form nature. The sole job of the antiglare ink is to lower the reflective surface properties of the outward facing foil surface during installation.
The required test methodology for determining reflective aluminium foil emissivity is ASTM-E 408. Reference to this Standard can be found within the new AS/NZS 4859-1:2002, “Materials for the Thermal Insulation of Buildings”
The position of AFIA is that there is no pre-determined generic emissivity value for the range of antiglare products on the Australian market. It is a matter for products themselves to have declared their emissivity under ASTM-E 408 if they are to claim a reflective airspace value in situ.
In a recent submission to the committee responsible for the upgrade of the House Energy Rating Scheme (HERS) software, AFIA has requested that the committee take this approach, and it has been suggested that a set of tables could be developed to show a range of emissivity values in the order of;
- e = < 0.10
- e = 0.10 – 0.20
- e = 0.20 – 0.4
- e = > 0.40
DE-RATING RECOMMENDATIONS FOR DUST
As a result of significant debate between insulation related industry participants AFIA sought the input of former Director of Australian Institute of Tropical Architecture, James Cook University, Townsville, Queensland, Professor Richard Aynsley, Ph.D to assist the Association in researching historical data on the effects of dust accumulation on aluminium foil surfaces in-situ.
The de-rating recommendations found in the dust paper, which can be viewed on this site, are the findings of Professor Aynsley who, now resides as Faculty Dean, Southern Polytechnic State University, School of Engineering Technology and Management, Marietta, GA, USA. The paper outlines in quite specific detail Professor Aynsley’s findings which show after great research and consultations with related industry experts in the USA there is little evidence to support or suggest de-rating of aluminium foils in-situ in Australia to the degree some industry participants have suggested. The position of AFIA therefore is that it accepts Professor Aynsley’s findings since no additional field research exists from Australian sources and AFIA has forwarded these details to various industry and Government instrumentalities for acceptance of the report.
AFIA GETS REFLECT-3 LICENCE
AFIA has recently acquired the Australian and New Zealand licensing rights to operate and use the REFLECT-3 computer software program re-developed under licence also in the USA by Southern Polytechnic State University, School of Engineering Technology & Management, Marietta, GA. The project team was led by Professor Richard Aynsley; Faculty Dean of the Georgia State University.
REFLECT-3 is a software tool for calculating Total or System R-values of parallel-sided air filled cavities up to 90mm wide, of either reflective or non-reflective surfaces. The objective of the program is to calculate into computational format the R-values of cavities below and above reflective radiant barrier membranes, (RBM), reflective foil laminates, (RFL) and segmented reflective foil insulations in ceilings, roofs, floors and walls.
The calculating capacity of the program has the ability to define foil surface emissivity and roof pitch orientation. The program also allows for the effects of thermal bridging which are calculated through definition of products used. This is usually a complicated process that can only be achieved by experienced qualified users. The program has been validated against physical measurements by Oak Ridge National Laboratory, USA (ORNL) for cavities up to 90mm wide.
Input Controls Are:
- Mean temperature and temperature difference across the cavity
- Emissivity of each side of a cavity
- Width of air space between layers (accommodates up to three 90mm reflective cavities)
Outputs From REFLECT-3 Are:
- R-values for vertical, 45 degrees and horizontal orientation
- Temperature difference across each air space
- Mean temperature and temperature differences across the assembly
Due to the nature and complexities of non-parallel surfaces in roof spaces, these cannot be computated using REFLECT-3, but can be calculated using ASTM C1340 developed by ORNL. For more information on this Standard please contact the AFIA help line.
[ Visit the REFLECT-3 Website ]
