Stage 1+2 | Stage 3 | Stage 4 | Stage 5
Treatment Stage 4 SEL Permavoid®
The SEL Permavoid® unit is specifically designed to create a structural void directly below the surfacing layers replacing granular sub-base. When the SEL Source Control System is appropriately designed, the SEL Permavoid® units can significantly reduce or eliminate the requirement for dangerous deep excavation, and this is particularly beneficial where digging causes expensive problems such as in areas with high water tables or contamination.SEL Permavoid® can be used to provide either attenuation (when encapsulated in impermeable membrane) or infiltration (when encapsulated in geotextile). The infiltration performance can be further optimised by using the SEL Permavoid® in a narrow vertical orientation. This arrangement provides two parallel faces with large surface area typically only 150mm or 300mm apart, thus maximising water flow into the ground. SEL Permavoid® is highly voided (95%), high strength and creep resistant. When used as a component of the SEL Source Control System a further treatment phase is provided by the dilution of residual pollutants over large areas. As the unit is highly voided there are no barriers to this process as there would be within a typical stone formation.
Key Features
- Provides a fourth water treatment phase within the SEL Source Control System
- Shallow construction, minimises residual excavated material
- Large surface area to depth ratio provides exceptional infiltration performance, in turn reducing attenuation volume requirement
- Satisfies designers’ risk assessments in accordance with CDM
- Manufactured from recycled material and also recyclable
- Unique jointing system (SEL Permatie) provides creep resistance
- Provides a high strength rigid raft for construction
- Lightweight and easily handled (3Kg per unit)
- Replaces sub-base, minimises the requirement for imported aggregates