SEC. 91.7109. ADDITIONAL REMEDIAL MEASURES.

91.7109.1. General Remedial Measures. In the event the concentration of methane gas in any building located in a Methane Zone or Methane Buffer Zone reaches or exceeds 25 percent of the minimum concentration of gas that will form an ignitable mixture with air at ambient temperature and pressure, the owner shall hire an engineer to investigate, recommend and implement mitigating measures. These measures shall be subject to approval of this Department and the Fire Department.

91.7109.2. Abandoned Oil Well. (Amended by Ord. No. 185,587, Eff. 7/16/18.) Any abandoned oil well encountered during construction shall be evaluated by the Fire Department and may be required to be re-abandoned in accordance with applicable rules and regulations of the Division of Oil, Gas and Geothermal Resources of the State of California. Buildings shall comply with these provisions and the requirements of LAMC Section 91.6105, whichever is more restrictive.

TABLE 71. MINIMUM METHANE MITIGATION REQUIREMENTS (Amended by Ord. No. 185,587, Eff. 7/16/18.)

Site Design Level LEVEL I LEVEL II LEVEL III LEVEL IV LEVEL V Design Methane 0-100 101-1,000 1,001-5,000 5,001-12,500 >12,500 Concentration (ppmv) Design Methane Pressure 2 >2 2 >2 2 >2 2 >2 All (inches of water pressure) Pressures De-watering System 1 X X X X X X X X X Perforated P Horizontal X X X X X X X X X A Pipes S Gravel S Blanket I Thickness 2" 2" 2" 3" 2" 3" 2" 4" 4" V Under E Sub-Slab Impervious Vent System Membrane S Gravel Y Thickness S Surrounding 2" 2" 2" 3" 2" 3" 2" 4" 4" T Perforated E Horizontal M Pipes Vent Risers X X X X X X X X X Impervious Membrane X X X X X X X X X A Sub-Slab Mechanical C System Extraction X X T System 2 I Gas V Detection X X X X X X X E Lowest System 3 Occupied Mechanical S Space Ventilation X X X X X X X Y System 3, 4, 5 S Alarm X X X X X X X T System E Control Panel X X X X X X X M M Trench Dam X X X X X X X X X I Conduit or Cable Seal X X X X X X X X X S Fitting C.

S Y Additional Vent Risers X S 5 T E M

For SI: 1 inch = 25.4 mm. X = Indicates a Required Mitigation Component

1. See LAMC Subdivision 91.7104.3.7 for exception.
2. The Mechanical Extraction System shall be capable of providing an equivalent of a complete change of air every 20 minutes of the total volume of the Gravel Blanket.
3. The mechanical ventilation systems shall be capable of providing an equivalent of one complete change of the lowest occupied space air every 15 minutes.
4. Vent opening complying with LAMC Subdivision 91.7104.3.4 may be used in lieu of mechanical ventilation.
5. The total quantity of installed vent risers shall be increased to double the rate for passive system.

DIVISION 72 FIRE DISTRICT REGULATIONS

(Division 72 Added by Ord. No. 170,953, Eff. 3/17/96, Oper. 1/1/96.)

91.7200 Purpose. 91.7201 General. 91.7202 Additions to Buildings. 91.7203 General Requirements. 91.7204 Special Requirements for Fire District Number 1. 91.7205 Provisional Structures. 91.7207 Special Requirements for the Very High Fire Hazard Severity Zone. 91.7208 Prohibited Vehicles.