If you or your client are at the pre planning stage, have a planning condition or need to satisfy building control you may require an Attenuation tank or Soakaway sizing design to demonstrate the attenuation volume required.
The output is a pdf document which provides the attenuation volume required.
What we require:
- Address and Postcode of development
- Roof Area in plan (m2)
- Other (non roof) impermeable ground surface area which discharge to drain/attenuation tank (m2, a runoff coefficient of 0.95 will be assumed unless otherwise stated)
- Allowable discharge rate (l/s). Usually provided by planning within the planning conditions, Building control depending on the stage of project or the Water company.
- Flow Control Device if specified or FlowBrake assumed i.e lowest blockage risk option.
- Climate change factor will be based on DEFRA's climate change allowance map assuming an epoch for development with a lifetime between 2061 and 2125.
- Design Storm period (if specified, otherwise 1 in 100 year summer storm assumed)
- Anticipated loading of tank/soakaway (<3T = min 0.27m cover, 12T = min 0.65m cover, 40T = min 0.85m cover, 60T = min 1.02m cover)
- Site constraints. Typically invert level of receiving sewer so that the proposed system can discharge by gravity.
- Preferred plan dimensions/constraints (e.g. 6m x 4.2m, standard crates measure 1.2l x 0.6w x 0.42h m)
If you are combining attenuation with rainwater harvesting the additional info is required:
- No of bedrooms of proposed development
- use of rainwater - toilet flushing, toilet flushing and irrigation, toilet flushing machine washing and irrigation
Simply post these details in the notes or email technical with your order number as the subject line.
The pdf will be delivered to the email address you have registered with.
- Allow 10 working days for the output to be delivered from supply of information requested above.
- Information requested is required to complete the calculation. The calculation cannot be commenced until the information requested is provided by the client in the format requested above.
- Calculation revisions charged at £50+VAT.
Some lead times may be extended due to consecutive bank holidays.
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The delivery information page is divided into 1. Specific and 2. General delivery information below.1. Specific Delivery Information relating to product lines
- Small items dispatched daily with RM24 ~85% arriving next day
- Large items (UK made) typically 5 - 15 working days (Parcelforce/Tuffnells etc.)
- 1,000 litre compact underground rainwater tank
- Prestige Greco Roman Terracotta Style Vase Planter - Washed Terracotta
- SAR 40 Stormwater Pumping Station
- Green Roof sedum tray - pre planted option
- Powertank Compact 125l
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Covid delivery updates between 12.3.20 and 11.1.21 21 have been archived here.