Climate Resilient Design

s regard. Policy NZ.5 Climate Resilient Design To protect occupants from the impacts of climate change, especially in a context of increasing energy efficiency in buildings, applications for new-build major development (10+ homes or 1000m2 floor space) should meet the following expectations. 1. Demonstrate that overheating risk measures have been selected in accordance with the cooling hierarchy, where the earlier steps should be pursued before resorting to the later steps: a. Minimise internal heat generation through energy-efficient design and specification b. Minimise the amount of heat entering the building in summer, using: i. Building orientation ii. Shading iii. Albedo (reflective or light-coloured external materials) iv. Fenestration and insulation. c. Manage heat within the building through exposed-internal thermal mass and high ceilings. d. Passive ventilation. e. Mechanical ventilation. f. Active cooling measures as a last resort. 2. Detailed overheating assessment is encouraged, comprising the following methodologies by CIBSE21: a. CIBSE TM52 for non-residential development b. CIBSE TM59 for residential development. c. Within this, applicants are encouraged to use future weather files (CIBSE Design Summer Year’ [DSY] for 2050 or 2080) as opposed to a DSY based on previous decades’ weather. Where the building passes the applicable overheating assessment using these future weather files, this will be recognised as a significant benefit in climate adaptation. Policy Justification 6.1.22 Climate change is anticipated to increase average annual temperatures, the occurrence and intensity of extreme weather events including heatwaves, wildfires, flooding, drought and storms. Ensuring that new development and changes to existing buildings respond to these changes is therefore a crucial element in responding to the climate emergency and will create more resilient communities, ecosystems and the economy for the future. 6.1.23 Climate resilient design is an approach to development that considers current and future climate conditions to optimise building performance and energy efficiency, as well as reducing the impact of development on the natural environment. The core principles of climate resilient design include adapting to higher temperatures through passive and natural cooling measures, reducing water consumption, managing flood risk and mitigating biodiversity loss. 6.1.24 This policy sets out the climate resilient design requirements for new development and changes to existing buildings. 6.1.25 While the Council is aware that there are national building regulations relating to overheating risk mitigation (Part O), that regulation allows two possible routes to compliance: A basic/simplified route, and an enhanced/dynamic route. The regulation allows most developments to follow the basic/simplified route, which may not be suitable to deal with future years’ increased overheating risk in the changing climate, and also does not reflect the potential effects of the enhanced energy efficiency targets set by this local plan’s separate policies NZ.1 and NZ.2. Additionally, Part O only covers residential developments and therefore fails to protect people from overheating risks in their place of work, study or leisure outside the home. 6.1.26 Because the space heat demand target set by policies NZ.1 and NZ.2 is tighter than the standard that would be achieved by current Building Regulations, these buildings will be more effective at holding on to heat that gets inside them, unless careful design choices are made to avoid excess unwanted heat and to manage and 21 Chartered Institute of Building Service Engineers remove this where it occurs. Without careful application of the cooling hierarchy (which prioritises passive means first), developers might otherwise resort to seemingly simpler technological solutions such as air conditioning which can have heavy energy use and may undo some of the carbon savings that the local plan is aiming to achieve. 6.1.27 Therefore, the basic route to compliance with Building Regulations on overheating is not considered sufficient. Instead, applicants are asked to utilise the industry’s best practice overheating risk mitigation assessment method, CIBSE TM52 or TM59 (for non-residential and residential respectively). 6.1.28 Applicants should note that CIBSE TM59 aligns with the enhanced/dynamic route to compliance with national Building Regulations Part O. 6.1.29 The policy therefore does not contradict nor duplicate Part O, but specifies the Council’s preferred route to compliance within Part O, and extends this to non- residential buildings too so that South Warwickshire’s new build employment and learning spaces will be equally ready for the increased frequency and intensity of heatwaves that the UK is alr