Approved Document Part L update

In our series of articles on Part L and the up-and-coming changes, Gurprit Bassi, Wintech’s Associate Director, Façade Engineer & Sustainability Lead, looks at some of the notable differences that will affect the industry.

Approved Document Part L (ADL) 2022 is a step change in the guidance for the conservation of fuel and power, towards even more meaningful developments which are due to be implemented in 2025 in the Future Homes Standard.

Several changes have been made which aim to improve energy efficiency and conservation and increase renewable energy generation. Under the new regulations, CO² emissions from new build homes must be around 30% lower than current standards and emissions from other new buildings, including offices and shops, must be reduced by 27%. A number of changes have been made to ADL1: 2022 for dwellings.

Some of the significant differences to the notional building include;

• A lowering of the U value for windows, decreasing from 1.4 to 1.2 W/m2k, which may now increase the likelihood of the use of triple glazing double glazing units.
• Wastewater heat recovery units and photovoltaic systems have now been added to improve energy conservation and increase renewable generation, respectively.
• There are a number of marginal improvements to the limiting fabric parameters for thermal performance and air tightness. The new values stated are not overly demanding and are unlikely to impinge any additional onus to developers, with lower values typically used currently to meet other requirements, such as the targeted fabric energy efficiency (TFEE) and target emission rates (TER).

Gurprit adds, “Much additional prescriptive guidance has now been added for insulation continuity, thermal bridging and airtightness. The guidance now applies prescriptive constraints and considerations onto the façade design in order to achieve thermal efficiencies. In addition, further prescriptive guidance and considerations are given for installation practices and standards, to ensure the quality of the construction. Photographic evidence is now a requirement to ensure that the guidance for the continuity of the insulation and thermal bridging is met. Further changes and additional guidance have also been made to consider the effects of thermal bridging (see link). The need to embed Façade Engineers into the design and construction process from RIBA stages 2 to 5 of large-scale dwelling construction projects is now of even greater importance”.

Furthermore, for new dwellings, the operating and maintenance instructions should include a Home User Guide. The Home User Guide should contain non-technical advice on how to operate and maintain the dwelling in a healthy and energy efficient manner and contain advice on ventilation, heating and domestic hot water, on-site electricity generation (if applicable) and staying cool in hot weather.

Wintech, as an established façade consultancy, are well versed and experienced in undertaking and consulting on façade design, site construction audits, and to check that dwelling facades are designed and installed in accordance with the new prescriptive guidance of ADL1: 2012, as well as all other applicable guidance, standards and codes of practice.

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