Gas leak

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A gas leak refers to a

• gas venting emissions which are controlled releases, and often practised as a part of routine operations, or
• "emergency pressure releases" which are intended to prevent equipment damage and safeguard life.

Gas leaks should also not be confused with "gas seepage" from the earth or oceans - either natural or due to human activity.

Fire and explosion safety

Pure natural gas is colorless and odorless, and is composed primarily of

Gas leaks can damage or kill plants.[4]^[5] In addition to leaks from natural gas pipes, methane and other gases migrating from landfill garbage disposal sites can also cause chlorosis and necrosis in grass, weeds, or trees.^[6] In some cases, leaking gas may migrate as far as 100 feet (30 m) from the source of the leak to an affected tree.^[7]

Harm to animals

Methane is an

Methane, the primary constituent of natural gas, is up to 120 times as potent a greenhouse gas as carbon dioxide. Thus, the release of unburned natural gas produces much stronger effects than the carbon dioxide that would have been released if the gas had been burned as intended.^[9]

Leak grades

In the United States, most state and federal agencies have adopted the Gas Piping and Technology Committee (GPTC) standards for grading natural gas leaks.

A Grade 1 leak is a leak that represents an existing or probable hazard to persons or property, and requires immediate repair or continuous action until the conditions are no longer hazardous. Examples of a Grade 1 leak are:

• Any leak which, in the judgment of operating personnel at the scene, is regarded as an immediate hazard.
• Escaping gas that has ignited.
• Any indication of gas which has migrated into or under a building, or into a foreign sub-structure.
• Any reading at the outside wall of a building, or where gas would likely migrate to an outside wall of a building.
• Any reading of 80% LEL, or greater, in a confined space.
• Any reading of 80% LEL, or greater in small substructures (other than gas associated sub structures) from which gas would likely migrate to the outside wall of a building.
• Any leak that can be seen, heard, or felt, and which is in a location that may endanger the general public or property.

A Grade 2 leak is a leak that is recognized as being non-hazardous at the time of detection, but justifies scheduled repair based on probable future hazard. Examples of a Grade 2 Leak are:

• Leaks Requiring Action Ahead of Ground Freezing or Other Adverse Changes in Venting Conditions. Any leak which, under frozen or other adverse soil conditions, would likely migrate to the outside wall of a building.
• Leaks requiring action within six months
• Any 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.
• Any 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.
• Any reading less than 80% LEL in small substructures (other than gas associated substructures) from which gas would likely migrate creating a probable future hazard.
• Any reading between 20% LEL and 80% LEL in a confined space.
• Any reading on a pipeline operating at 30 percent
  specified minimum yield strength (SMYS) or greater, in a class 3 or 4 location,^{[clarification needed}
  ] which does not qualify as a Grade 1 leak.
• Any reading of 80% LEL, or greater, in gas associated sub-structures.
• Any leak which, in the judgment of operating personnel at the scene, is of sufficient magnitude to justify scheduled repair.

In 2017, Rhode Island released an estimated 15.7 million metric tons of greenhouse gases, about a third of which comes from leaks in natural gas pipes. This figure, published in 2019, was calculated based on an assumed leakage rate of 2.7% (as that is the rate of leakage in the nearby city of Boston). The study's authors estimated that fixing the leaks would incur an annual cost of $1.6 billion to $4 billion.[10]

Regulation

This section needs expansion. You can help by adding to it. (July 2014)

Massachusetts

Legislation passed in 2014

Additional proposals not included in the law would have required grade 3 leaks to be repaired during road construction, and priority for leaks which are killing trees or which were near hospitals or churches.[14]^[15]

An attorney for the Conservation Law Foundation stated that the leaks were worth $38.8 million in lost natural gas, which also contributes 4% of the state's

]

History

This section needs expansion. You can help by adding to it. (November 2013)

Catastrophic gas leaks, such as the Bhopal disaster are well-recognized as problems, but the more-subtle effects of chronic low-level leaks have been slower to gain recognition.

Other contexts

This section needs expansion. You can help by adding to it. (November 2013)

In work with dangerous gases (such as in a lab or industrial setting), a gas leak may require hazmat emergency response, especially if the leaked material is flammable, explosive, corrosive, or toxic.

See also

• Gas detector
• List of pipeline accidents in the United States
• Merrimack Valley gas explosions
• 2022 Nord Stream pipeline sabotage

References