54 RCI 0514

RCI May 2014

INSULATION Simple route to low CO2 By Tony Millichap, technical manager at Kingspan Insulation The implementation of the latest Approved Document L1A (ADL1A) last month provided an opportunity to look forward and consider the best approaches to meeting the upcoming zero carbon targets. Given the cost and limited lifespans of renewable technologies, solutions which can avoid the use of these are clearly more desirable. Structural Insulated Panels (SIPs) offer a balanced fabric first approach to achieving zero carbon targets, providing excellent building envelope performance with low thermal mass, along with minimal levels of thermal bridging and air loss. Achieving compliance Under ADL1A 2013, a new Fabric Energy Efficiency Standard has been introduced. Compliance is achieved if the Dwelling Emission Rate (DER) and Dwelling Fabric Energy Efficiency (DFEE) meet or exceed the Target Emission Rate (TER) and Target Fabric Energy Efficiency (TFEE). The TER and TFEE being defined by a new 2013 Notional Dwelling Specification. This approach still allows the performance of the differing components described in the Notional Dwelling Specification to be varied, subject to certain limits. The high levels of building fabric performance delivered by SIPs can easily allow a property to comply with the new requirements whilst specifying building services, windows and doors that are simpler and cheaper than those assumed in the Notional Dwelling Specification. Alternatively, it takes very little to improve the performance of a SIP construction beyond these new requirements, to that required for Passivhaus standards. Two ADL1A 2013 compliant scenarios, modelled with SAP 2012, are outlined in Figure 1. They are based on Kingspan TEK Building System panels 054 MAY 2014 RCIMAG.COM which comprise a 112mm high performance rigid urethane insulation core between two sheets of OSB, for the walls. In the first scenario, the specification comfortably surpasses the requirements of ADL2013 with no renewables and with many other areas of the specification relaxed from that described in the 2013 Notional Dwelling Specification. In the second scenario, with only simple additional measures to enhance the U-Value of the building fabric, dwellings can be constructed which greatly surpass the ADL 2013 requirements, helping to not only reduce CO2 emissions, but also minimise fuel bills for occupants over the long-term. In this scenario, a 30mm layer of Kingspan Thermawall TW55 is installed on the inside of the Kingspan TEK Building System panels, and other dwelling elements are brought up to the level of the new Notional Dwelling Specification (see fig. 1). Scenario 1 Scenario 2 Floor U-Value W/m2K 0.20 0.13 Wall U-Value W/m2K 0.19 0.14 Roof U-Value W/m2K 0.16 0.11 Airtightness m³/m²/hr @ 50pa. 1.0 1.0 Thermal Mass Low (100) Low (100) Thermal Bridging Bespoke SIP psi-values Bespoke SIP psi-values Additional Relaxations from Notional Dwelling Specification 75% low energy lighting Door & Glazing 1.6 W/m2K Programmer, Roomstat, TVR No Weather Compensator Additional Improvements over Notional Dwelling Specification MVHR Windows 1.2 W/m2K MVHR A-rated heating pump TER 19.36 19.36 ADER 18.27 (5.6% better) 14.50 (25.1% better) TFEE 50.40 50.40 DFEE 45.50 36.60 Figure 1: Example Specification Comparison


RCI May 2014
To see the actual publication please follow the link above