Environmental Engineering and Contracting

Arroyo Geoscience Inc., Geotechnical Engineering, Glendale, CA
Arroyo Geoscience Inc., Geotechnical Engineering, Glendale, CA

A-HAZ Engineering Contractor Lic. No. 1062092

Everything You Need To Know About Methane Mitigation Systems

An important factor to consider when building in Los Angeles is the presence of the natural gas methane in the soil.
Methane molecules 3D rendered illustration

Expert Methane Mitigation Assessment, Design, and Construction

An important factor to consider when building in Los Angeles is the presence of the natural gas methane in the soil. After a few unfortunate incidents of fires and explosions in LA County resulting from methane buildup, in 2004 the Los Angeles County Department of Public Works Building and Safety passed ordinance number 175790, requiring all new construction in LA County to pass methane inspection before permitting would be allowed. For properties where methane is detected, a methane mitigation system must be installed.

Finding the right partner to (1) assess your property, (2) design a custom methane mitigation system, and (3) follow the design perfectly in installation, can save your project thousands of dollars and days of critical building time.

At Applied Earth Sciences, we’re dedicated to bringing your project in safely, on time, and on budget.

What Is Methane Gas?

Methane is a colorless, odorless, and highly flammable gas, and the main component in natural gas. It is lighter than air, and can be formed in multiple ways. The two types of methane gas most applicable to building in California are biogenic and petrogenic methane.

Biogenic methane is produced as a side effect of decaying organic material in a low oxygen environment, like what can often be found in bogs, marshes, or landfills.

Petrogenic methane, as its prefix indicates, is formed from a thermal decomposition of petroleum. Petrogenic methane can be found where petroleum was found or processed, even years after the fact.

Both types of methane gas are harmful to humans and pets. In large enough accumulated quantities, methane can reduce the amount of breathable oxygen in an enclosed space (becoming an asphyxiant), can fuel a fire, or if compressed can even combust on its own. At room temperature and with a concentration level of just 5%, methane can explode spontaneously.

In California, it is not unusual to find both biogenic and petrogenic methane readings at the same site. Since both are harmful to humans, both need methane mitigation systems to make them safe.

What Is A Methane Mitigation System?

A Methane Mitigation System is a designed procedure to attenuate the concentration of methane gas that can leak up through the soil under a property. There are many different methane mitigation systems. The right fit is determined based on site testing, foundation plan and footing detail, and architectural site plan and cross sections. An expert engineering firm such as AES can develop a methane mitigation system around your existing building plan, preventing the need for costly rearchitecting.

Most custom mitigation systems will use multiple techniques to dissipate or redirect methane. Combining techniques allows for built-in failsafes and increased efficiency of each component. Some examples of methane mitigation system components include:

  • Passive Methane Ventilation – This is a structure that will allow gas vapor to do what it does naturally; rise. But rather than rising into your basement, it will follow the path of least resistance set up by a passive methane ventilation design, which will output the gas outside, allowing it to dissipate naturally.
  • Physical Methane Barriers – Vapor barriers will physically prevent methane release from leaking up through your building materials. Creating an airtight vaporlock under your foundation won’t prevent methane buildup, but it will protect you from undirected methane finding its way into your building. When combined with these other techniques, a physical barrier is a valuable failsafe.
  • Active Methane Extraction and Ventilation – In addition to the passive ventilation options, for more serious cases you can also actively extract the methane from the soil. Our HVAC experts design efficient fans for blowing or vacuuming excess vapor. Our environmental engineers can also use active systems to induce pressure gradients under your structure, forcing the methane to safer areas. There are a variety of techniques both hi- and low- tech that can protect you from vapor leak.
  • Methane Sensors / Alarms – Lastly, a methane mitigation system can include sensors to detect methane buildup. An alarm system can either be passive, simply triggering an alert to notify a building manager, or active, automating the active methane extraction and ventilation systems to mitigate the buildup.

What Is The Cost of Active California Residential Methane Mitigation System?

Please write to us to ask for a free quote. One size does not fit all, as your methane mitigation system will be custom designed and constructed to fit the parameters of your project. We offer the most economical quality Methane Mitigation System around.

The Benefits of a Tight Engineering + Contractor Partnership

Since 2013, we have collaborated with our trusted associates at Applied Earth Sciences to offer full white glove service for all three phases of Methane Mitigation Systems that a construction project will need in LA County. We have worked alongside Applied Earth Sciences to perform over five hundred methane mitigation system installation projects over the last 20 years.

The designer of any methane mitigation plan needs to be in constant communication with the construction team, as well as the methane deputy inspectors. Having a tight working relationship with a geological engineering contractor means there are no translation errors when the designs need to be carried out. We also handle scheduling and consultation work directly with Applied Earth Sciences, meaning you are never waiting on the next phase. Testing, design, and construction can all happen faster with Arroyo Geoscience.

What Makes Applied Earth Sciences Special?

Applied Earth Sciences has been in business since 1985, providing geotechnical engineering expertise to hundreds of developments in Southern California. We have a large cross-functional team that combines years of experience with a rigorous research mindset, meaning we have seen it all but also are constantly looking for a better way to get the job done.

All of our projects are unique, and we take pride in providing the best service to our clients.
Further, because of our special relationship with the geotechnical engineering contractor Arroyo Geoscience, we can offer services that other geological consultants need to outsource. Knowing how to design to our contracting partners means we can save our clients time, money, and hassle.

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