Soil Gas Migration Services
Gas leaks from underground gas lines occasionally cause house fires and even explosions. Whether from large high-pressure gas transmission pipelines, gas mains, or lower pressure residential service lines, gas will sometimes migrate underground through the soil, enter a structure, and, then, cause a fire or an explosion. Natural gas companies perform periodic gas leak surveys where they use sensitive gas sensing equipment to detect existing leaks. This is an effective way to detect small, existing leaks and then repair the leaks in a responsible time frame.
Bison Engineering is the leader in the investigation of soil gas migration incidents. The relevant studies conducted on underground gas leaks at pipeline pressures normally encountered in urban environments has been conducted by Bison. Bison has collected and presented to AGA, IAAI and other gas and fire investigation associations.
See also: Integrated Metallurgical Analysis, Carbon Monoxide Testing Equipment
Over the past thirty years, Bison has collected and analyzed data on many pipeline leaks and has been able to form opinions and conclusions regarding gas migration through the soil and how it might cause gas explosions. Bison has tested and observed many different conditions that exist after a gas fire or explosion. Some of the questions that have been asked are:
- What caused the gas leak?
- How long did the gas leak exist prior to the explosion?
- What was the flow rate into the structure?
- What route did the gas take?
Soil Gas Migration Observations and Misconceptions
What we have found from observing conditions of numerous other incidents is that many common assumptions are frequently not valid. Some of the facts that we have found are:
- The commonly held theory that natural gas migration “follows” a pipeline is often unverified or incorrect.
- Gas, under pressure, can flow in any direction including downward in the soil from the leak source.
- Gas can migrate through the soil much farther and faster than is typically assumed.
Our Experience In Soil Gas Migration Cases
How do we know these facts? We have performed bar hole testing (sampling the gas levels at many locations and depths in the soil) at the sites of the incident, recorded and analyzed that data, and have found that the factual data we have collected simply does not support the common assumptions made about soil gas migration. We have observed the conditions of many different gas fires and explosions and have reviewed extensive literature on the subject. No other company has examined this issue as thoroughly as Bison Engineering.
With thirty years of experience collecting soil gas data, analyzing that data and forming conclusions specific to each incident, there is no other forensic investigation company more qualified to investigate an incident with questions regarding soil gas migration than Bison Engineering. Call us right away!