A housing development on a former coal mining site needed to be investigated as ingress of carbon dioxide gas at levels potentially dangerous to residents had been identified. The access points of the gas needed to be pinpointed and the effectiveness of remediation works monitored and measured.
Three properties were identified as having known or potential carbon dioxide gas ingression. AmbiAir units were used to monitor carbon dioxide levels in the properties, positioned in locations close to potential points of entry and in the breathing zone of occupants.
The EPG team decided on AmbiAir as it’s a non-specialist solution that is also small and unobtrusive, an important factor as these devices were being used in residential properties. Monitoring in the houses with AmbiAir cost less than 10% of the cost of traditional continuous gas monitoring equipment making it suitable and possible to obtain data in more locations. Another key decision-making factor was the predictive alerts generated by Ambilytics which were critical; the EPG team set up thresholds that would alert them if the gas levels reached unhealthy and unsafe levels for the residents, allowing them to proactively and remotely manage the risk.
Nine AmbiAir devices were placed in strategic locations across all three properties and each beside points of service entry including the bathrooms and kitchen. All nine units ran off the one LoRaWAN gateway, which made the set-up simple.
Continuous monitoring, a basic part of the AmbiAir solution and the integration of related weather data by Ambilytics ensured that the worst-case conditions in case of rapid pressure drop were captured in real-time. For the multiple lines of evidence assessment, the data from the Ambilytics platform was combined with that from other monitoring techniques completed at the site, including analysis of ground investigation data, surface-emission surveys, and flux box tests to build the conceptual model for the site.
In the end, EPG took a pragmatic approach to the ground gas risk, advising simple remediation works for the existing properties that had mine gas in them. The AmbiAir units were critical in allowing EPG to verify that these remedial works, sealing up a duct in this case, were effective. They were also able to monitor numerous locations for a fraction of the cost of traditional gas monitoring.