Environmental Sustainability in Design & Access Statements Wales

This is a summary of how environmental sustainability should be covered in Design & Access Statements (DASs) in Wales, based on the requirements of the Welsh Assembly Government’s Technical Advice Notes TAN 12 and TAN 22, and on Chapter 4 of Planning Policy Wales (PPW). (TAN 22 was officially launched at the Greener Homes and Buildings Show in Builth Wells on 4th June 2009 by Jane Davidson, AM.)

Although predictions of climate change due to human activity vary widely, it is generally considered that Wales will suffer:
• heavier rains, leading to flash flooding and stress on sewerage systems
• drought, and
• heat
(presumably not all at once!)

With the longer term in mind, responding to climate change right now is a priority. Our response is in two forms: reduction of climate change drivers (in particular carbon emissions) and resilience to predicted changes (especially flooding and heat).

The favoured approach for reducing carbon emissions is the Energy Hierarchy – firstly reduce energy needs by passive design; secondly use energy efficiently by insulation and air-tightness; thirdly use low/zero-carbon (LZC) technologies. Passive design looks at shading, shelter and solar gain by considering positioning, orientation, fenestration, and choice of site.

Green roofs have many benefits – they can contribute to thermal stability and biodiversity, and they attenuate surface water runoff.

Environmental sustainability at design & procurement can be increased by choice of materials and responsible sourcing, while during occupation it will be increased by designing for water efficiency and providing recycling facilities.

These aspects of design and construction, and many others, are covered by the Code for Sustainable Homes. Accordingly it is a planning requirement in Wales for new dwellings to achieve Code Level 3, with 1 credit in Ene 1 (dwelling emission rate).

At Outline stage the DAS should incorporate the results of a Code pre-assessment, including the predicted credits for Ene 1 and total score, along with statements on:
• how carbon reductions will be achieved,
• how the design takes account of climate change,
• what design solutions are proposed, and
• how conflicting requirements have been, or will be, resolved.

The recommended approach calls for:
• an argument for the feasibility of achieving the required Code standards
• integration of the pre-assessment into the DAS
• clear wording for the local community and other stakeholders
• comprehensive yet concise coverage (of external aspects only)
• a treatment in proportion to the size or special nature of the development

Although incorporating pre-assessment is an added burden in the creation of a DAS, the intention is to avoid problems later in attaining the required Code standards. The complete process includes attaining Interim Code certification before construction starts, and Final certification before occupation. Thus the Code certification process is intertwined with the planning process.

It has to be remembered that this approach is the WAG’s response to the serious threats posed by climate change, and is its method of meeting carbon-reduction targets.

 

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