Methane Mitigation Systems for Buildings
A methane mitigation plan eliminates the hazards of methane soil gas intrusion. Without proper methane mitigation, vapors can migrate through foundations and into buildings. This causes an accumulation of methane gas and leads to explosive and asphyxiation hazards.
In Los Angeles, these plans are created for projects within Methane Zones or Methane Buffer Zones. Additionally, plans require review and approval of the building department. Furthermore, design parameters of a methane mitigation system are based on the results of a methane soil gas test.
The geologists and engineers at Geo Forward, Inc. are experienced with the latest design standards and building codes. Geo Forward, Inc. specializes in designing these systems for commercial and multi-tenant residential projects. Moreover, Geo Forward, Inc. specializes in subterranean parking garages, underground vaults, basements and more. Comprehensive mitigation plans summary reports are provided. Lastly, Geo Forward, Inc. provided construction support and oversight. Call us at (888) 930-6604 to speak with a licensed geologist or engineer.
City of Los Angeles Methane Mitigation Requirements
The City of Los Angeles established high-risk “Methane Zones” and “Methane Buffer Zones.” These zones may require mitigation. For properties in a Methane Zone or Buffer Zone, the needs to abide by the Los Angeles Department of Building and Safety (LADBS). Per Ordinance No. 175790 of the Los Angeles Municipal Code, buildings shall provide a methane mitigation system based on the appropriate Site Design Level. A Site Design level is based on the data reported during the methane soil gas test.
There are five LADBS Site Design Levels. Each requires different parameters. The methane mitigation requirements increase with each Site Design Level. Mitigation Plans can include specialized ventilation systems that are either “Passive” or “Active.”
Passive Vapor Mitigation Systems
Passive Methane Mitigation Systems (also referred to as Passive Ventilation Systems) are designed to remove methane gas from the subsurface, without mechanical influence. A Passive Methane System relies on the natural rising characteristics of methane to capture the accumulations of gas underground. The gas naturally flows upwards into the atmosphere by earth pressure.
Active Vapor Mitigation Systems
Active Methane Mitigation Systems (also referred to as Active Ventilation Systems) are comprised of subsurface gas extraction systems. These systems are blower or pump activated. Moreover, HVAC systems accelerate indoor ventilation. Additionally, an Active Methane Mitigation System includes methane gas sensors and an alarm system. This warns occupants of peaking methane concentrations.
De-watering & Waterproofing in Methane Mitigation
De-watering systems lower the groundwater table to a level below the bottom of a soil-gas ventilation system. Waterproofing barriers prevent groundwater from passing through a methane barrier. Geo Forward, Inc. specializes in designing de-watering systems and waterproofing barriers. This process involves communication with the architects and local building departments.
For more information about methane mitigation plans, call (888) 930-6604 to speak with an expert.
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