(A) A soil gas investigation to identify the concentration of methane gas in the subsurface is required if any of the following situations apply:
(1) Construction within the city's methane zone which meets either of the following (subsequently referred to "regulated construction'):
(a) New commercial/industrial construction.
(b) Modification to existing structures when the valuation of the modification is equal to or greater than 25% of the assessed value of the existing structures.
(2) The granting of a subdivision map, conditional use permits necessitating ground disturbance, or development plan approval, when the property falls within the city's methane zone.
(3) Existing conditions at the site warrant a soil gas investigation in the opinion of the Fire Chief or his designee.
(B) The methane zone is that area depicted on the city's methane zone map. The methane zone encompasses land in the city which is within 1,000 feet of a landfill or within 500 feet of an existing or abandoned oil well. The city's methane zone map is adopted by reference as if set forth in full in this section. A copy of the city's methane zone map is available for public inspection on the city's website or at city offices during regular business hours.
(C) A minimum of two soil gas monitoring wells are required for all regulated construction. Additional monitoring wells are required based on the size of the proposed project. One additional monitoring well is required per 10,000 square feet of building area for buildings exceeding 20,000 square feet. An alternative proposal as to the number of monitoring wells may be considered at the discretion of the Fire Chief.
(D) General monitoring and mitigation requirements for regulated construction within the methane zone:
(1) Prior to construction, obtain approval from the Fire Department for a soil gas investigation showing the proposed location(s) and design of the monitoring wells, in accordance with § 117.131(C).
(a) Monitoring wells shall initially be sampled at least two times within a period of seven days.
(b) The initial sampling shall not occur within two days of precipitation for first sampling event or at any time between the first and second sampling event.
(2) Soil gas shall be monitored quarterly after construction is complete. All soil gas monitoring reports required by this section shall be sent to the Fire Chief. If the permanent monitoring well locations are different than the location of the initial monitoring wells, approval from the Fire Department is required prior to installation of the permanent monitoring wells. If the quarterly monitoring reveals methane levels less than 25% of the lower explosive limit (i.e., 1.25% by volume in air or 12,500 ppm/v) during the first year, the system shall be monitored annually thereafter. In cases where methane levels are less than 2.5% of the lower explosive limit (i.e., .125% by volume in air or 1,250 ppm/v) the Fire Chief may waive the annual monitoring requirement upon written request. The granting of the waiver shall be at the discretion of the Fire Chief.
(E) Based on the results of the soils gas monitoring or on information available on surrounding properties, property owners shall implement any other mitigation measures as required by the Fire Chief.
(F) In lieu of the initial soil gas investigation, a methane mitigation system approved by the Fire Department may be installed.
(G) Methane mitigation systems shall be required for any regulated construction if any of the following apply:
(1) The initial monitoring reveals methane levels in excess of 25% of the lower explosive limit (i.e., 1.25% by volume in air or 12,500 ppm/v).
(2) The regulated construction will impede access to an abandoned oil well.
(3) Quarterly or annual monitoring reveals methane levels greater than 25% of the lower explosive limit (i.e., 1.25% by volume in air or 12,500 ppm/v).
(H) Where regulated construction takes place in the methane zone and which incorporates sensitive land uses (e.g., residential developments, places of public assembly, hospitals, restaurants, schools, and the like), a methane mitigation system may be required regardless of the methane levels detected at the discretion of the Fire Chief.
(I) The design of a methane mitigation system for property within the methane zone shall be in accordance with the requirements of the Los Angeles County Department of Public Works and City Fire Department.
(J) If required by the Fire Department, the building owner shall be responsible for ensuring that annual inspections of the methane mitigation systems are completed. Reports of these inspections shall be conducted under the oversight of a registered petroleum engineer or other qualified persons and submitted to the Fire Department. A fine shall be charged, as established by resolution of the City Council, for each methane mitigation system found to be inoperative or improperly maintained.
(K) Methane barrier systems shall include permanent monitoring vapor probes above and below the barrier unless an alternative design is approved by the Fire Chief.
(L) In extraordinary cases, e.g., where methane in excess of 25% of the lower explosive limit (i.e., 1.25% by volume in air or 12,500 ppm/v) can be demonstrated to be a non-repetitive incident, a registered petroleum engineer or other qualified
persons may request a waiver by the Fire Chief for the installation of a methane mitigation system. The granting of the waiver shall be at the discretion of the Fire Chief.
(M) Where gas detection systems are used, they shall be designed by and installed under the supervision of registered engineers. The design and installation shall be inspected and approved by the Fire Department.
(1) Following installation, a readily visible sign shall be posted which reads: "Gas Detection Alarm. In the event of an alarm, evacuate the building and call the Fire Department, 911. Do not disconnect under penalty of law."
(2) The property owner shall provide Fire Department access to the alarm panel and the building in which it is installed as well as the alarm reset code by means of an approved key box system. Keys shall be clearly and permanently identified.
(Ord. 1104, passed 8-8-19) Penalty, see § 10.97
Cross-reference:
Misdemeanor offenses, see § 117.004