Draft Regulation 18 Sandwell Local Plan

Managing Heat Risk

5.34 As part of the plan's proactive approach towards mitigating and adapting to climate change, Policy SCC3 sets out the requirements for managing heat risk within new development proposals.

Justification

5.35 Global temperatures are rising, and this has been paralleled by changes in the weather in the UK. The Met Office published a document^[97] in 2022 outlining current trends and predictions in the UK, including the following:

2.1 … The average temperature over the most recent decade (2009-2018) has been on average 0.3°C warmer than the 1981-2010 average and 0.9°C warmer than the 1961-1990 average. All the top ten warmest years for the UK, in the series from 1884, have occurred since 2002.

5.36 The urban heat island effect^[98] is caused by extensive built-up areas absorbing and retaining heat during the day and night, leading to those areas being several degrees warmer than their surroundings. With higher temperatures across the country, the likelihood of heat being trapped in this way is very likely to increase.

5.37 Retained heat can become problematic, to the point where circumstances can lead to physical discomfort and disruption, but for those with certain health conditions, the very young or the elderly, the effects can be serious. The use of green roofs and / or walls can provide some mitigation by shading roof surfaces and through the mechanism of evapotranspiration.

5.38 The concept of thermal inequity^[99] will also have relevance in areas of the Black Country including Sandwell, whereby because of uneven social geographies, urban heating effects impact disproportionately on poorer / marginalised communities living in urban environments. This is exacerbated by a planning policy approach that concentrates development in urban areas, at higher densities and in taller forms. The removal of urban greening and trees to facilitate increased development densities will have further adverse effects on ambient temperatures in the vicinity.

5.39 Certain aspects of building design intended to increase energy efficiency and reduce heat demand, such as increased glazing and airtightness, can also exacerbate heat risk and cause uncomfortable living conditions. Design solutions can be found in the hierarchy proposed in Policy SCC3.

5.40 Means of minimising heat risk may include, though not be limited to, inclusion of mitigation measures such as:

1. solar shading, for instance through landscaping or brise-soleil^[100],
2. using appropriate materials in areas exposed to direct sunlight,
3. using landscaping and permeable surfaces to mitigate against flooding / run-off, counter poor air quality and allow for heat absorption.

5.41 Mechanical air conditioning will use more energy and generate significant amounts of additional greenhouse gases and thus should be avoided where possible.

5.42 As addressed in Policy SNE3, the use of trees in landscaping schemes can generate significant natural shading. The layout and orientation of new houses should also be considered carefully, to avoid existing or newly-planted trees creating excessive shading during cooler, darker times of the year.

5.43 In addition to this, the Canal and River Trust and the University of Manchester collaborated on a 2019 study that demonstrated that canals can effectively act to cool adjacent buildings in urban areas. The research showed that there is likely to be a cooling effect between 0.3°C and 1.6°C within a 100-metre-wide corridor of the canal during the hottest hours of the day (the variation in temperature was from differing orientations of the canals tested and the configuration of the surrounding buildings)^[101]. Where canals and other bodies of water exist adjacent to development sites, opportunities to make use of this feature should be incorporated into designs where possible.