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Foul Sewers and Lateral Drains

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• Pipe serving one property• Not adoptableDrain

• Outside the curtilage• Connects to a sewer

Lateral Drain

• Serves more than 1 property• Have an outfall Sewer

Sewers and Lateral Drains

All types of sewers and lateral drains must take drainage from buildings

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• Access to clear blockages

• Pipes preferable in accessible areas

• Proximity to buildings

• Proximity to trees

• Minimum depth

Layout

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Approved Document H1 Foul Drainage – 2.51“Access points to sewers (serving more than one property) should be in places where they are accessible and apparent for use in an emergency. Examples of suitable locations include highways, public open spaces, unfenced front gardens and shared or unfenced driveways.”

Access to clear blockages

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A Sewerage Undertaker requires to be able to rod or jet to any point on the public sewer system from an accessible access point.

Functional requirement

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Layout example

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Pipes in accessible areas

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Courtyard access

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Archways

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Building over sewers – Requirement H4. (1)

“The erection or extension of a building or work involving the underpinning of a building shall be carried out in a way that is not detrimental to the building or building extension or to the continued maintenance of the drain, sewer or disposal main.”

Proximity to buildings – H4 requirements

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• The building should not damage the sewer

• If the sewer fails, it should not damage the building

• Should not obstruct maintenance

Approved document H

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Proximity to buildings

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Proximity to Buildings

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Proximity to Trees

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• Gardens (no vehicles) 0.35m• Domestic driveways (no HGV) 0.5m• Domestic driveways (HGV access) 0.9m• Agricultural Land 0.9m• Public Open Space 0.9m• Highways 1.2m

Minimum depth of cover to crown

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Access chambers

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Access chambers – Type 3

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Plastic chambers

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Type 4

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Small access chambers

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• 4000 litres per dwelling per day • Method from BS EN 752• Alternative method BS EN 12056-2

Hydraulic design

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• 0.75 litres per second – 1/3 design flow• Different calculation for small and large

sewers.

Self cleansing

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QUESTIONS?