|(a) Purpose and qualifications. Operators shall have until March 1, 2009, to repair Grade 2 leaks identified prior to September 1, 2008, and shall have until September 1, 2011, to repair Grade 3 leaks identified prior to September 1, 2008. For all leaks reported on or after September 1, 2008, operators shall comply with the requirements of this section. (1) The purpose of the leak grading system is to determine the degree or extent of the potential hazard resulting from gas leakage and to prescribe remedial actions. Each operator shall promptly respond to any notification of a gas leak or gas odor or any notification of damage to facilities by excavators or other outside sources. (2) Each operator shall ensure that leak grading is made only by those individuals who possess training, experience, and knowledge in the field of leak classification and investigation, including extensive association with actual leakage work. The judgment of these individuals, based upon all pertinent information and a complete leakage investigation at the scene, shall form the basis for the leak grade determination. Each operator shall ensure that its leak detection equipment is properly calibrated. (b) Grade 1 leaks. (1) A Grade 1 leak is an existing or probable hazard to persons or property and requires the operator to take action immediately to eliminate the hazard and make repairs. A Grade 1 leak includes but is not limited to: (A) any leak which, in the judgment of operating personnel at the scene, is regarded as an immediate hazard; (B) escaping gas that has ignited; (C) any indication of gas, which has migrated into or under a building, or into a tunnel; (D) any reading at the outside wall of a building, or where gas would likely migrate to an outside wall of a building; (E) any reading of 80% lower explosive limit (LEL) or greater in a confined space; (F) any reading of 80% LEL or greater in small substructures, other than gas associated substructures, from which gas would likely migrate to the outside wall of a building; or (G) any leak that can be seen, heard, or felt, and which is in a location that may endanger the general public or property. (2) A Grade 1 leak requires that the operator take prompt action to eliminate the hazardous conditions. The prompt action may require one or more of the following: (A) implementing an emergency plan (49 CFR §192.615); (B) evacuating premises; (C) blocking off an area; (D) rerouting traffic; (E) eliminating sources of ignition; (F) venting the area by removing manhole covers, barholing, installing vent holes, or other means; (G) stopping the flow of gas by closing valves or other means; or (H) notifying emergency responders. (c) Grade 2 leaks. (1) A Grade 2 leak is non-hazardous at the time of detection, but requires the operator to schedule repair based on probable future hazard. A Grade 2 leak, because of its location and magnitude, can be scheduled for repair on a normal routine basis with periodic reinspection as necessary. Each operator shall re-evaluate every Grade 2 leak at least once every 30 days until repaired or cleared. (2) Each operator shall repair within six months of detection any leak: (A) with a reading of 40% LEL, or greater, under a sidewalk in a wall-to-wall paved area that does not qualify as a Grade 1 leak; (B) with a reading of 100% LEL, or greater, under a street in a wall-to-wall paved area that has significant gas migration and does not qualify as a Grade 1 Leak; (C) with a reading less than 80% LEL in small substructures (other than gas associated substructures) from which gas would likely migrate creating a probable future hazard; (D) with a reading between 20% LEL and 80% LEL in a confined space; (E) with a reading on a pipeline operating at 30 percent SMYS, or greater, in a class 3 or 4 location, which does not qualify as a Grade 1 leak; (F) with a reading of 80% LEL, or greater, in gas associated substructures; and (G) which, in the judgment of operating personnel at the scene, is of sufficient magnitude to justify scheduled repair. (3) Grade 2 leaks vary greatly in degree of potential hazard. Some Grade 2 leaks, when evaluated by the criteria in this subsection, may require a scheduled repair within the next five working days. Others will require repair within 30 days. In determining the repair priority, each operator shall consider criteria such as the following: (A) the amount and migration of gas; (B) the proximity of gas to buildings and subsurface structures; (C) the extent of pavement; and (D) soil type and conditions, such as frost cap, moisture, and natural venting. (4) Each operator shall take action ahead of ground freezing or other adverse changes in venting conditions with respect to any leak which, under frozen or other adverse soil conditions, would likely allow gas to migrate to the outside wall of a building. (d) Grade 3 leaks. (1) A Grade 3 leak is non-hazardous at the time of detection and reasonably can be expected to remain non-hazardous. Each operator shall repair a Grade 3 leak within 36 months of detection. (2) Each operator shall re-evaluate each Grade 3 leak during the next scheduled survey, or within 15 months of date reported, whichever occurs first, until the leak is cleared, repaired, or re-graded. A leak requiring re-evaluation at periodic intervals includes any reading: (A) of less than 80% LEL in small, gas-associated substructures; (B) under a street in areas without wall-to-wall paving where it is unlikely the gas could migrate to the outside wall of a building; and (C) of less than 20% LEL in a confined space. (e) Post-repair inspections. (1) A leak is considered to be effectively repaired when an operator obtains a gas concentration reading of 0%. (2) For a repaired leak with a gas concentration reading greater than 0% at the time of repair, an operator shall conduct a post-repair leak inspection within 30 days after the repair to determine whether the leak has been effectively repaired. If the second post-repair inspection shows a gas concentration reading greater than 0%, the operator shall continue conducting post-repair leak inspections every 30 days until there is a gas concentration reading of 0%. If after six inspections have been performed the operator is unable to obtain a gas concentration reading of 0%, then the operator shall create a new leak report with a new leak grade determination. (3) Post-repair inspections are not required for leak repairs completed by the replacement or insertion of an entire length of pipe or service line, or for the repair of leakage caused by excavator or third-party damage, provided a complete re-evaluation of the leak area after completion of repairs verifies that no further indications of leakage exist. (4) Remedial measures such as lubrication of valves or tightening of packing nuts on valves which seal leaks are considered to be routine maintenance work and do not require a post-repair inspection. (f) Upgrading. When an operator upgrades a leak to a higher grade, the time period for repair is the remaining time based on its original classification or the time allowed for repair under its new grade, whichever is less. This requirement does not apply to leaks that, at the time of discovery, an operator has classified at a lower grade pending a further, more complete investigation of the leak hazard area. (g) Table. The following table provides a concise reference for leak grading and leak repair deadlines.