Soakaway Sizing Design Calculation BRE 365/CIRIA 3D
If you or your client are at the pre planning stage, have a planning condition or need to satisfy building control you may require a Soakaway sizing design to demonstrate the soakaway volume required.
The output is a pdf document which provides the soakaway dimensions required.
The calculation will be performed as per CIRIA 3D method as standard. The BRE 365 method can be used by request only.
What we require:
- Address and Postcode of development
- Roof Area in plan (m2, a runoff coefficient of 0.95 will be assumed unless otherwise stated)
- Other impermeable ground surface area which discharge to drain or to the soakaway (m2, a runoff coefficient of 0.90 will be assumed unless otherwise stated)
-
Infiltration rate, determined by an Infiltration test
- 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. For Wales 40% allowance will be used.
- Design Storm period (if specified, otherwise 1 in 100 year summer storm assumed)
- Design Rainfall Data, FSR assumed, FEH available for an additional fee.
- Safety factor of 1.5 will be assumed unless specified otherwise.
- Urban creep will be assumed as zero unless specified otherwise.
- 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)
- Preferred plan dimensions/constraints/maximum dig depth (e.g. 6m x 4.2m, standard crates measure 1.2l x 0.6w x 0.42h m). Invert level of incoming pipe if already in situ.
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.
Notes
- Allow 10 working days for the output to be delivered from supply of information requested.
- 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.
If your query is related to an existing order please email in with your order number in the subject line. If you have a new residential enquiry please consult the online guides before calling as they may answer your question.
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/APC etc)
- 1,000 litre compact underground rainwater tank
- 250 litre Prestige large Plant Pot style planter Grey
- SAR40-TOP2 Wastewater Lifting station
- 250 litre Classic Slim Wall Water butt - Black Granite
- Madison 185 Litre rain barrel
- Hydraloop
- Green Roof sedum tray - pre planted option
- Madison 185 Litre rain barrel - Millstone
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Covid delivery updates between 12.3.20 and 11.1.21 21 have been archived here.