Methane Mitigation Construction
Once a Methane Mitigation Design is approved by the Los Angeles Department of Building and Safety, the design implements within the project.
The Methane Mitigation Construction must complete by a specialty contractor that is licensed and certified to do so.
During Construction, A Methane Deputy Inspector will have to oversee and approve the installation. https://www.youtube.com/watch?v=WYp9ilxafcQ
Why must I do smoke and thickness tests on my methane vapor barrier?
Quality control of methane barriers is an essential aspect of Methane Mitigation Construction. Previously, spray-applied membranes were extremely difficult to install. They require high skill and relevant expensive equipment. Spray-applied membranes are extremely easy to incorrectly install. Which will result in a methane barrier that has insufficient membrane thickness.
The thickness of the standard spray-applied asphalt emulsion methane barrier material is 60 mils. There is a high chance of accidentally installing one with a lower thickness during the methane mitigation construction. A Methane deputy inspector is a requirement to have them regularly on site to oversee the installation of a methane barrier. It is the contractor’s responsibility to ensure that they are meeting the design specifications. Still, it is the responsibility of the Methane deputy inspector to verify the results of the methane test. To confirm that the methane barrier installment is correct per the manufacturer’s and the design engineer’s requirements.
To ensure that sufficient spray-applied material is installed correctly, a thickness test measuring Methane barrier coupon thickness is conducted.
At approximately every 500 ft.², a coupon is cut out of the membrane. It is measured with a caliper by the Methane deputy inspector to ensure thickness complies within design requirements. If the methane barrier is lacking sufficient thickness, the methane deputy inspector is required to inform the contractor. So that they must continue to install and spray the methane barrier until sufficient thickness is reported.
This can take a significant amount of additional time. So it is important that the contractor in use has experience in Methane Mitigation systems to ensure that schedules don’t deter. If a Methane barrier lacks sufficient thickness, then it requires a minimum of an additional day to install the methane barrier again with the correct thickness.
In addition to thickness Tests, Methane Mitigation insulations will require a smoke test. Naturally, frequent void holes and inadequate sealing of seams or termination points will be present on the methane barrier during its construction and insulation. However, it is sometimes difficult to accurately locate these insufficiently sealed seams or voids. This is why a smoke test happens 24 hours after the curing time of the methane barrier.
The smoke test conducts with pressurize smoke in position beneath the foundation where membrane is applicable.
This happens so that if any leaks occur, smoke emerging from the seams will make them easily patchable on site immediately. This ensures that there are no voids or areas of possible leaks within the membrane. After completing the smoke test, the Methane Mitigation contractor and deputy inspector will certify that the Methane barrier installation occurs correctly. So that no further testing or insulation will be a requirement.
At this point, the contractor responsible for laying down the rebar and pouring concrete has requirements to continue with their work. This is a susceptible aspect of the Methane Mitigation Construction because it is likely that any failure in rebar installation could induce damage onto the Membrane. Although there is a protective sheet typically appliacable on top of a membrane to reduce possible damages, this is not a full-proof method of protection. Construction workers must be diligent in identifying holes and preventing any additional holes from forming inside the membrane. This is why it’s a rule for deputy inspectors to constantly be on site during the installation of rebar. So they monitor the crew and ensure that no damage induces onto the methane barrier.
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