Major Contributing Factors to Natural Gas Pipeline Leaks
There are several factors that contribute to gas pipeline leaks according to independent gas safety expert Bob Ackley of Gas Safety USA. In order of importance they are: (1) the type of pipeline material that’s used, (2) the date of installation of the pipeline, (3) the type of pipeline coating (if any); and (4) the cathodic protection (if any). Cathodic protection (CP) is a technique used to control the corrosion of a metal surface.
This is also true of plastic pipes which were first used in the early 1970s. They are still in use in some locations, have quickly deteriorated, and are being replaced.
Leak-Prone Pipes and Notification to Property Owners
According to Ackley, “Cast iron and bare steel are leak-prone pipe but more importantly cast iron pipes are prone to cracks that can result in very hazardous situations. If anyone has a small diameter cast iron pipe near their home they should be informed of the inherent hazards involved with the use of such old pipe.”
Ackley said that, “These property owners should be told to treat any odor of gas as a potentially hazardous situation. Any property owner that has a leak that has migrated to the root zone of any tree should be notified of the condition and the date of expected repair. Gas operators have a duty to notify property owners (and municipalities) that the faulty operation of the gas system is damaging private property.”
He recommends that everyone know the location of their curb valve and meter shutoff cock.
Gas Mains in the Street
The same goes for the gas main or mains in the street which could be and most likely are different than the service line.
Ackley said that:
- The operation of the system includes the gas mains and service lines. Either one could have leaks and resulting vegetation damage.
- Gas leaks that are killing trees are most often from cast iron joint leakage or corrosion on steel mains.
- Service lines are most often steel or plastic with some copper and to a much lesser extent cast and wrought iron.
- Cracked cast iron mains spread quickly and usually result in grade one emergency leaks that are immediately repaired.
- The outstanding leaks are for the most part corrosion and mechanical failures that typically do not (but can in some instances) produce enough volume to blow up a building and are complicit in the exploding manhole problem.
New Categories of Leaking Gas Pipes
Ackley suggests classifying leaking gas pipes into the following four major categories:
- Natural forces earth movement / frost: Cracks in cast iron mains or other pipeline ruptures
- Third party damage: Pipes that are hit and damaged by others
- Corrosion: Pipes that are rusting
- Mechanical failure: Leaking joints on cast iron pipes
Ackley’s Report to Community Leaders
The following report was made by Ackley to the 2E Advisory Neighborhood Commission (ANC), Citizens Association of Georgetown (CAG), and Ward 2 Councilmember Jack Evans on September 17, 2018:
The good news is that most of the leaks that Gas Safety Inc. and other independent experts have detected in Georgetown and across Washington are not necessarily explosion hazards for buildings, but many leaks are complicit in exploding manholes throughout the District. Typically, a failure in utility substructures that results in a subterranean fire will draw into the structure any leaking gas that may be in the area and build up the gas concentration to explosive level, causing the manhole to explode. Those of us in the industry know that when the explosion occurs, most of the leaked gas has now been combusted and zero or very low natural gas readings are recorded after the explosion.
https://www.wired.com/2013/03/dc-exploding-manholes/
Here is an incident from 2018:
I believe this was explained to the ANC Commissioners as the District has a history of exploding manholes and the exploding manholes were referenced on page 6 of the report to PSC.
Washington Gas Light has a duty to repair any existing hazards upon detection of leaks. A leak that is a potential future hazard is typically monitored every six months until repaired or replaced with a new gas main.
But the bad news is that no community can afford to be lulled into a false sense of confidence about the safety of their gas pipelines. To paraphrase [former House Speaker] Tip O’Neill, “All gas pipeline safety issues are local.” Indeed, last Thursday’s gas pipeline-related leaks, explosions and fires outside of Boston or other similar disasters could be repeated in Georgetown and thousands of other communities around the country. The added problem in your community is that it may take up to 30 years for a main replacement project to be completed, depending on where that particular street is on the replacement list.
In addition to safety concerns, there are also pressing gas pipeline-related environmental issues. Many so-called “grade 3” leaks are killing public shade trees as indicated by our work in DC last year. This is settled science. Washington Gas Light knows all about the proven link between leaking gas pipelines and the death of street trees, but they have not taken any steps to address this important matter.
Natural gas operators around the country have been allowing leaks to go on for years to save money on the operator maintenance budget and ignore the inherent hazards from natural gas. Any place that there is a natural gas pipe, let alone an existing leak, has the potential to be complicit in an incident where a building or manhole could explode. Any location where there is an existing natural gas leak should be checked for safety first and if any vegetation is being damaged (trees, shrubs, lawn or other vegetation) should have a required repair within a reasonable timeframe.
Ignoring these and other gas pipeline-related issues will not make them go away. Although cities, states, and their regulators may have ultimate jurisdiction over these matters, it’s often the smaller neighborhoods and communities and their leaders who speak up and band together that are the true catalysts for improvements and reforms.
Feel free to contact me with any questions or concerns.
Regards,
Bob Ackley
508-344-9321
DC Gas Leaks 