Contaminated Land Gas Reception Sump

Description

Sub-floor depressurisation is a way of reducing the pressure beneath a building and therfore directly influencing / easing the extent by which it seeks to infiltrate the construction.

Located beneath the floor slab in non-suspended floor configurations, one or more draw-sump is incorporated within the granular fill. The sump is connected and vented to the atmosphere using 110mm drainage pipe. Such sump configurations are termed passive and rely on the imbalance of pressure under and outside of the structure to naturally evacuate and dissipate gases. External termination dissipation options include Cavibricks, high-level pipe outlets or alternatively the outlet can receive an external cap in preparation to receive optional fan assistance at a later date.

One sump can influence an area up to 9 metre radius or an area odf up to 250 square metres where the granular fill are is continuous and uninterrupted. How many sumps are required to provide optimum depressurisation depends on the foundation construction of the building and whether orv not there is ventilated masonry between thise foundtion areas. Where a high-water table exists we recommend sump integration is reviewed to ensure functionality is not compromised by being waterlogged. (Note pressure differential requires the surface separating below ground from above ground to be sealed / capped not open).