CampbellReith has utilised the existing guidance on ground gas on a number of schemes to progress from generic ground gas assessment to detailed gas flow and vapour models and use of forensic ground inspection to assess the ground gas potential.
The provision of robust ground gas protection measures can present significant engineering challenges (particularly when membranes or such like are required in basements or complicated floor arrangements). The practice completes the detailed assessment of gas protection measures in order to consider these within the broader engineering context. Such evaluations can in turn present potential opportunities for cost and programme savings.
Examples of this area presented in case studies associated:
- CampbellReith was appointed by the University of Greenwich to provide a full range of land quality and waste appraisal services for their multi storey School of Architecture and Construction and a Library, with ground floor retail and exhibition space. The development included a major basement excavation and construction which in the initial design included both ‘tanking’ provisions and also a proprietary gas membrane. CampbellReith undertook a detailed quantitative modelling of volatile ground gas. This enabled the omission of high cost gas protection measures which were originally included as part of the remedial measures. The assessment was submitted to and was awarded Finalist at the Ground Engineering Awards 2013.
- CampbellReith was appointed by Crest Strategic Properties to provide a remedial design for a former landfill. CampbellReith modified the remediation strategy in order to utilise forensic soil descriptions (based upon CL:Aire RB17) in order to allow the soils excavated from former landfill to be screened and classified for reuse. Upon completion of works, surface gas emission scans, flux box monitoring and traditional borehole monitoring was implemented in order to allow the assessment of residual passive ground gas designs for the proposed housing. The approach allowed the site to be redeveloped despite previously having elevated ground gas concentrations without the need for extensive post construction gas monitoring.