78


INSULATION Cutting details down to psi


Jonathan Ducker from Kingspan Insulation GB explores how the industry has developed a range of details to assist specifiers pursuing higher thermal performance


There is a raft of manufacturer-created and industry-created details and guidance now available, reflecting actual build-ups and performance, complete with associated psi values


A


s part of the recent updates to the energy efficiency requirements in the Building Regulations and


Standards in England, Scotland and Wales, there has been a notable effort to close the performance gap between the design and actual energy performance of buildings. This gap can be significant, with testing showing that total energy use from some new homes can be as much as 250% higher than expected. In particular, the new regulations look to raise practice around addressing thermal bridges – implementing a range of measures to encourage the use of designed insulation details for junctions and to ensure that the original specification is carried through into the final building.


Why thermal bridges matter Thermal bridges (also known as cold bridges) are areas where materials


WWW.ARCHITECTSDATAFILE.CO.UK


which are more conductive to heat than the insulation, are allowed to form a ‘bridge’ between the internal and external parts of a construction. These can act as a fast-track for heat to escape and can account for as much as 30% of total heat losses from a property. This means addressing them is a key step to ensuring a good level of fabric performance. Thermal bridges typically occur because of gaps or inconsistencies in the insulation layer and are common in areas such as junctions between the wall, floor and roof; junctions around openings such as windows; and at penetrations such as pipework.


The heat losses at these junctions are measured as psi-values (Ψ). Heat losses at penetrations through layers can also be measured as chi-values (χ). A lower value represents lower expected heat losses.


ADF NOVEMBER/DECEMBER 2023


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84