Southwest
Environmental LimitedSouthwest
Environmental Limited| London |
| 02076 920 670 |
| Exeter |
| 01392 927 961 |
| Manchester |
| 01612 970 026 |
| Bristol |
| 01173 270 092 |
Below is some feedback we received following pre-app advice with Bristol City Council.
All new development in Bristol should be designed with the future climate in
mind through climate change mitigation & adaptation techniques. Mitigation
and adaptation measures must be integrated into the design. Mitigation
Sufficient information has been provided on climate change adaptation measures. The proposal conserve water through water efficiency measures and limit water use to 1051/p/d is noted and supported. However further information should be provided to demonstrate how the development will meet the following points;
The layout of the site should be designed to mitigate extreme temperatures brought about by climate change. Orientation, form, massing and planting for shade should be carefully considered so that both internal and external spaces are comfortable in hot weather.
The building design should mitigate extreme temperatures and risk of overheating brought about by climate change. This should include good thermal mass, living walls and roofs, open able windows, canopies, and external shading, and avoiding single aspect units. This is particularly important for rooms on S and SW sides of the building. South facing elevations will receive more direct solar radiation around midday when the sun is high in the sky. South-west facing elevations will receive solar gains when ambient external temperature is at its highest, making the rooms on both South and South West elevations more prone to overheating. The extent of glazing to the W facing rooms should be carefully considered as these may receive unwanted solar gains from low level sun in the evenings. We'd recommend that overheating risk analysis (e.g. following CIBSE TM59/TM52 guidance/other as appropriate) is carried out based on dynamic thermal modelling in order to understand the implications of future projected temperatures (e.g. in 2030 and 2050) on the development in order to mitigate the risks appropriately and ensure a comfortable internal environment is provided without the need for energy consuming cooling equipment.
Further guidance produced by the NHBC foundation/zero carbon hub on understanding overheating and design options for mitigation can be found here. Assessments using the steady state conditions SAP compliance tool are not appropriate for the purpose of demonstrating compliance with the policy requirement (i.e. for site layouts and approaches to design and construction which provide resilience to climate change) because this tool does not factor in future climate impacts. Development should minimise flooding through the use of sustainable drainage systems — please refer to comments from flood risk manager.
Development should include blue & green infrastructure to both mitigate the urban heat island and reduce surface water runoff. DM15 requires that new GI assets are designed to be multifunctional, and expects the provision of additional and/or improved management of existing trees as part of new development. Minimal green infrastructure is proposed. Further greening is required for example through provision of a green/ green-blue roof with a deep substrate and minimal/no sedum blanket areas. Development should avoid responses to future climate impacts leading to increases in energy use (e.g. air conditioning systems). 20f5
The calculation methodology (SAP12) is in line with Bristol policy, however the baseline energy calculation is not policy compliant. This needs to include a policy compliant heating system, not electric heating as currently included as this results in high baseline emissions compared to other policy compliant heating systems. The calculations must be revised and a revised energy statement and table submitted.
The energy efficiency measures proposed are acceptable.
The heating system proposed (electric heating) does not comply with the BCS14
heat hierarchy. The site is within the heat priority area and nearby to an
emerging heat network in the St Pauls area and is therefore required to
incorporate infrastructure to enable connection to forthcoming networks in the
future. i.e a wet communal heating system. In accordance with the
heat hierarchy, the preference is for this to be served by a renewable heating
system such as air source heat pumps. These could be located at roof
level. The applicant should provide a revised energy statement setting out
how the BCS14 heat hierarchy will be met through provision of a policy
compliant heating source.
The proposal for PV is supported and this will meet the 20% reduction in C02
below residual emissions requirement.
The proposals set out in the sustainability statement do not set specific targets for construction waste reduction/diversion from landfill. A Site Waste Management Plan should be conditioned to include these targets. The storage for bins and recycling should be provided in line with Bristol Waste's recycling planning guidance. — see comments from Bristol Waste on the proposal.
The water efficiency proposals are acceptable. Further consideration of the
use of rainwater harvesting is encouraged.
Materials
The proposal for the use of A and A+ -rated BRE Guide materials in 80% of the major building elements as set out in the sustainability statement is supported.
There do not appear to be proposals to enhance biodiversity or green infrastructure on site. In addition to BS15 requirements about enhancing biodiversity, the Site Allocations and Development Management Plan also links to biodiversity (DM15 and DM29). Biodiversity enhancement options could include; sustainable drainage systems such as green roofs, brown roofs, living walls, tree pits, swales, attenuation ponds to reduce surface run off and improve water quality, wildlife areas, the inclusion of bird and bat boxes and the planting of fruit/ nut bearing trees. Green roofs should be specified with deep substrate depths to support a greater variety of species, hold significantly more rainfall, have a greater thermal mass and have greater evapotranspiration properties. Revised proposals setting out proposals to enhance biodiversity should be submitted
The broadband statement submitted is for a different site. A revised assessment is required providing evidence of the provision of high-speed broadband access and enabled provision of 'Next Generation' broadband. Further guidance on demonstrating this policy requirement has been met can be found in the broadband connectivity practice note March 2018
This policy requires Flood resilience and surface water management. Please see comments from the flood risk team.