Spreadsheet for calculating required volume of attenuation tank. Storage of this type is used to limit peak rate of run-off from development to watercourse i.e. to allow water to be slowly discharged to sewerage system. This is calculated based on a range of annual flow rate probabilities. Features: - User friendly and very easy to use; - A clear and easy to read output (all on a single page); - Design required storage volume based on one or two outflow rates; - Pop-up window for easier selection of rainfall ratios - gives figures for larger cities; - Automatically calculates Z2 growth factor based on given rainfall ratio, M5-60 rainfall depth and rainfall duration; - Covers ten rainfall duration periods: M1-D, M2-D, M3-D, M4-D, M5-D, M10-D, M20-D, M30-D, M50-D, M100-D; - Adjustable allowance for climate change; - Covers two site locations: England and Wales, Scotland and Northern Ireland; - Quick summary of results; - Compatible with older versions of Excel, like Excel 2003; - Design is in accordance with CIRIA C697: 2007 (the SUDS manual) & BRE Digest 365
