Continuous ground gas flow monitoring: What this means for risk assessment

23Apr / 2018

Continuous ground gas flow monitoring: What this means for risk assessment

Continuous monitoring has revolutionised ground gas risk assessment allowing for a detailed understanding of the conditions of a site. The introduction of continuous ground gas flow monitoring brings another line of evidence that is relatively easy to understand and interpret. What impact will this have on ground gas risk assessment?

When is continuous ground gas monitoring suitable? 

In any ground gas risk assessment, sources, pathways and receptors must be identified and accurately characterised in the pollutant linkage assessment. Sources often include infilled land (such as landfills), natural strata with organic rich content (such as peat deposits) or land that has been contaminated by previous use (such as gas works and other industrial processes).

Figure 2: Deployment of GGS continuous ground gas flow instrument.

Figure 2: Deployment of GGS GasSentinels® continuous ground gas flow instrument.

It is important to identify the worst case ground gas risk in order to recommend appropriate remedial measures. Current generic guidance is often too conservative for many sites, and continuous ground gas flow monitoring can assist in determining the specific remedial measures required for a particular development.

Previous to the introduction of continuous ground gas flow monitoring, data was often supplemented by periodic “spot” readings of gas flow. Flow measurements taken periodically are often affected by ground conditions and barometric pumping, rather than a result of gas generation. Continuous ground gas flow monitoring helps pull apart the real gas regime at a site from often confusing and misleading periodic flow measurements. This means increased data accuracy and higher quality risk assessments.

How can GGS help?

Our new fleet of GasSentinels® with continuous flow has further enhanced our capability to provide accurate lines of evidence to our clients to ensure that appropriate ground gas protection measures are installed in developments. Through high quality monitoring and risk assessment, expensive protection measures are avoided on those sites where they’re not needed.

The GGS GasSentinels® are specially designed to continuously monitor ground gas concentrations and flow. They fit comfortably within standard 8-inch upright or flush well covers (see Figure 1 and 2) providing a discreet service and a practical solution to sites where access and security are difficult. GGS also offers insurance to clients for instrument damage or theft so there are no hidden or unexpected fees for replacing the equipment.

Figure 1: GGS continuous ground gas flow monitoring instrument in situ

Figure 1: GGS continuous ground gas flow monitoring instrument in situ

All GGS engineers are extensively trained and have experience in deploying these instruments in a variety of settings. Quick decision making on site by our engineers often saves our clients time and money, leading to faster response times to problems. GGS service packages also include deployment, maintenance and collection of equipment on site, so if anything goes wrong, we’ve got it covered.

GGS processes and presents the continuous flow monitoring data in our market leading graphs (see Figure 3),  making it easier to interpret and therefore identify the significant relationships between ground gas concentrations, flow and environmental parameters. The aim is to provide clients with confidence in their understanding of the ground gas regime.

GGS has almost ten years of continuous monitoring and risk assessment experience and is the only specialist company that can provide a complete service from instrument deployment, data processing, and factual reporting to, when required, full risk assessment and outline remedial design.

GGS’ reputation for reliably delivering a high quality service, underpinned by continuous innovation and market leading technology,  ultimately means that clients save time and money. Adopting continuous flow is further evidence of the company’s commitment to continuously improve its service to its clients.

GGS’ continuous ground gas flow monitoring services can help you:

  • Reduce risk
  • Avoid expensive corrective measures
  • Speed up planning and building control approval
  • Provide time and cost savings

 

To discuss how our continuous monitoring services can benefit you, call 0161 232 7465 or email [email protected]

Figure 3: GGS continuous monitoring results including atmospheric pressure (top), gas concentrations (middle) and flow (bottom)

Figure 3: GGS continuous monitoring results including atmospheric pressure (top), gas concentrations (middle) and flow (bottom)

 

Find out more on our website:

Continuous ground gas monitoring

Continuous monitoring data packages

Continuous monitoring data management