Thermal Bridging Study Shows Mannok’s Aircrete Thermal Blocks Perform up to 750% Better Than Dense Concrete Blocks.

A recent study has shown that Quinn Lite thermal blocks will deliver a massive 750% improvement in Psi Values at key junctions, over and above those achievable with dense concrete blocks. In addition, the study has also revealed over 200% improvement in Psi values to those achievable with lightweight aggregate blocks.

It goes without saying that thermal blocks should be used to reduce heat loss through thermal bridging, but this study reveals that the choice of thermal block is equally as important.

The study was conducted by independent NSAI accredited Thermal Modeller, Andrew Lundberg, who is recognised as one of Ireland’s leading specialists in thermal bridge analysis and Passive House certification.

A total of 17 junctions were modelled, which compare the performance of three different blocks: standard dense concrete blocks, lightweight aggregate blocks, and Quinn Lite aircrete blocks. The junctions modelled were based on the DOE Acceptable Construction Details, which are widely used in the construction industry throughout Ireland.  At the critical location, one or more dense blocks were replaced with the alternative block, namely Quinn Lite and Lightweight Aggregate blocks, and the performance of the junction was analysed.

Results

In all 17 junctions the Quinn Lite range of blocks significantly outperformed the DOE Acceptable construction details, which would have been expected. The Quinn Lite blocks also outperformed the Lightweight aggregate block in all 17 junctions, with significant improvement at all the key locations.

Fig. 1. shows a typical ground floor to cavity wall junction, and the resulting Psi values for this junction based on a range of U-values, with and without drylining.

For scenario A, the most thermally efficient block in the Quinn Lite range, the Quinn Lite Super, improves the junction’s Psi values by 210% when compared to the lightweight aggregate block. In other words, the lightweight aggregate block will allow over three times as much heat to pass through the junction as the Quinn Lite Super.

Comparing the same Quinn Lite block in the same scenario with dense concrete blocks, the Quinn Lite improved the Psi value by over 750%!

Thermal Performance Coupled with Strength

In terms of thermal performance, the results are clear: Quinn Lite thermal blocks are the most superior concrete block manufactured in Ireland. However, Architects and Specifiers must also consider block strength in order to ensure compliance with Part A of the building regulations.

If using TGD A to prove compliance, a minimum compressive strength of 7.5N/mm² is required. The Quinn Lite Seven (B7) block meets this requirement. This block also meets the minimum thermal conductivity of 0.20W/mK as outlined in the DOE Acceptable Construction Details for use with the enhanced Psi values listed in Appendix D of TGD L.

When we compare Quinn Lite’s B7 to the closest alternative, the lightweight aggregate block, and another alternative, the Cellular Glass or Foamglas block, Quinn Lite are the only blocks which comply with both the enhanced Psi values and with compressive strength requirements of TGD A.

Implications for the Irish Construction Industry

This research comes at a time when the Irish construction industry is challenged with finding cost effective solutions to the upcoming nZEB (nearly zero energy buildings) standard.

The results highlight that not only can Quinn Lite blocks help achieve nZEB and Passive House standards through minimising thermal bridge losses, but it also throws a spotlight on the risks of substituting a specified Quinn Lite block with a lightweight aggregate block or other alternative on site. Due to the vast difference in thermal performance and the resulting Psi values, substituting Quinn Lite blocks for lower performing alternatives can ultimately result in non-compliance.

For further information, or if you have any queries, get in touch with our technical team on +44 28 67748866 or technical@quinn-buildingproducts.com
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