The SEL Car Park Drainage System is a complete Sustainable Drainage System (SUDS) that has been developed in line with current guidelines as set out by CIRIA, the Environment Agency and SEPA.

The SEL Car Park Drainage System

SEL offer a FREE review service for any proposed surface water drainage design. The review will allow SEL to assess the feasibility for a more cost effective arrangement which utilises source control to deal with run-off, a cornerstone of good Sustainable Design.

The SEL car park drainage system can be used to infiltrate or attenuate surfacewater run-off and incorporates multiple stages of water treatment within the constructed aggregate layers of car park pavement and other hard-standings, directly beneath the finished surface. The site is broken down into micro-catchments and the forward flow from each area is managed using SEL flow control chambers.

By using the SEL car park drainage system to deal with surfacewater run-off rather than end-of-line attenuation tanks, it is possible to minimise construction depths with the majority of any surfacewater attenuation storage tanks and pipe network within circa 500mm of the finished ground level.

There are further benefits through the reduction of drainage pipe diameters. A typical SEL car park drainage scheme will require pipework diameters of 150mm and 225mm. Reducing the diameters and installation depths will help reduce construction risks with no deep excavations.

Run-off generated by roof catchments can be attenuated within the car park drainage or within standalone storage tanks and rainwater recycling can be integrated with the SEL car park drainage system.

Key Benefits

SEL integrate the following range of source control techniques to achieve the above including 

  • Combined collection and source control drainage channels (Primary separation and treatment)
  • Floating oil treatment systems (Secondary Adsorption and Treatment)
  • Modular plastic sub-base replacement attenuation and conveyance structures (Attenuation / dilution)
  • Oil separation, retention and treatment textiles (Absorption and Treatment)
  • Mini silt / oil source control gravity separators (Primary separation and treatment)
  • Voided Sub-base (Filtration, treatment and Attenuation/ Infiltration)

Key Features

  • Complete Source Control SUDS solution for new build or retrofit developments
  • Replaces Oil Separators as defined by PPG3 (Pollution Prevention Guidelines) 
  • Six stages of water treatment available within the system 
  • Provides treatment at source by gravity separation and bio-degradation of oils and silts 
  • Provides attenuation or infiltration at source 
  • Replaces sub-base, minimises the requirement for imported aggregate 
  • Shallow construction, minimises residual excavated material 
  • Contributes to BREEAM ratings - Satisfies designers’ risk assessments in accordance with CDM 
  • Reduces the requirement for large diameter concrete chambers and pipes
  • Improves water quality 
  • A practical solution for the retrofit of SUDS components into existing drainage schemes 
  • SEL Permavoid® and other system components are manufactured from recycled material and are also recyclable and reusable
  • Resistant to frosts, salts and hydrocarbons
  • Can be installed with as little as 130mm cover