The virtual curtain is specifically designed for each site. Gas types, concentrations and flows are used to calculate the size and spacing of vent nodes that are inserted into the ground using a no-dig method to minimize the amount of excavation which is usually no more than 650mm deep.
 
The individual nodes are connected to a geo-cellular collector duct system which is wrapped in a geotextile.

The duct system is located within a shallow trench which is backfilled on completion of the Virtual Curtain System with selected as-dug material. The design will confirm the capacity, number and spacing of the above ground venting infrastructure.

The system is virtually maintenance free and has been widely accepted by regulators all over the UK.