Impervious Membrane: In accordance with the Los Angeles Department of Building and Safety (LADBS) Methane Code, Ordinance Number 175790, an impervious membrane is a continuous methane gas barrier. It is a crucial part of the methane mitigation process and underlies a building to impede the vapor intrusion of methane soil gas. An impervious membrane must comprise materials approved by the LADBS.
What is an Embankment Dam? An Embankment Dam is a freshwater-retaining structure comprising excavated rock, soil, or a combination of rock and soil from nearby geological formations. In fact, Embankment Dams are known as an “Earthfill Dam” when filled with soil, and a “Rockfill Dam” when filled with rocks. Earthfill Dams are most common. The…
Methane Mitigation Soil Gas Pressure Sensor Methane Mitigation Soil Gas Pressure Sensor: A Methane Mitigation Soil Gas Pressure Sensor is a device that measures and communicates sub-slab soil gas pressure to a methane control panel system. High levels of methane soil gas then trigger the integrated methane alarm system to notify occupants of danger. Much…
Poorly Graded Soil Poorly Graded: In the soil classification process of geology, poorly graded soil represents a sedimentary soil sample that only displays one or a few of the numerous other possible grain sizes for that soil classification, in accordance with the Unified Soil Classification System (USCS). For example, a poorly graded sand (SP) may…
Underground Storage Tank (UST) Underground Storage Tank (UST): An underground storage tank (UST) is a confined container occupying any volume of space within the subsurface, for the purposes of storing liquid. Underground tanks typically support commercial and residential services and have filling ports, ventilation pipes, and connecting product pipelines. Underground storage tanks (USTs) come in different…
Hydrogen Sulfide Soil Gas (In Natural Gas) Hydrogen Sulfide: Hydrogen sulfide (H2S) soil gas geologically occurs upon the thermal and microbial decomposition of subsurface organic material deposits. It is typically identifiable in biogenic and petrogenic natural gas sources, along with higher concentrations of methane soil gas. Additionally, nitrogen, oxygen, hydrogen, ethane, and isobutane exist within…
Consistency The term “Consistency” in the fields of engineering geology and geotechnical engineering means the degree of adhesion between soil particles within a sample, that are observed to resist deformation or rupture.
