Current through Reg. 49, No. 12; March 22, 2024
(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.
Attached
Graphic