National Grid writes that replacement does not prevent leaks on other gas pipes located in the same area. “Until each segment of leak prone pipe is replaced, new leaks can occur on the segments of leak prone pipe still in service. Indeed, leaks on the existing cast iron pipe would be expected to occur at an increasing rate year over year. ; [and] other factors such as nearby construction contributed to new gas leaks…Small diameter cast iron is most susceptible to bending stress and impact.” They mention the removal of pavement over shallow cast iron mains during road reconstruction.
In a 2022 article, GEOHAZARDS, I detail the many threats to pipeline integrity, all of which are likely to get worse and are beyond anyone’s capacity to control or mitigate. Any one of these threats would be reason to retire the pipes, but taken together, they call for the most effective solution, a plan to turn off the gas.
These geohazards include: saturated soil, rapid flooding, ice, frost heaves, frost jacking, rock indentation, erosion, corrosion, mudflows, debris flows, … subsidence, decompression cooling, lack of integrity of right-of-way, and hydro-technical issues upstream and downstream.
In addition to the geohazards, National Grid notes that pipe replacement does not prevent third-party damage or nearby construction on the new pipe — such as when a water, sewer or telecom company damages the main by not adhering to DigSafe requirements.
It reminds me of an incident on Eliot Street in 2017 when the DPW worker did not call DigSafe, used equipment too big for the curb project, lifted up pavement that included a gas turn off valve that was near the street surface and broke a 12” cast iron gas line.
National Grid’s list of pipeline threats include “Weather induced loads such as depth of winter frost penetration and frost action. They also cite, among other threats “Traffic loads”and “Construction impacts” (Yes! Cars are heavier than they used to be and there is more traffic than streets were designed to carry and there is heightened risk of construction damage such as the high pressure pipe break at the demolition site of the old Chestnut Hill theater.)
National Grid also writes that “Main breaks are a major concern due to the large amount of gas that may be released in such instances. This is made worse when the driving force behind the cast iron main leak is the operating pressure. Medium or high-pressure cast iron aggravates the safety threat posed by cast iron mains.”
“Cast iron breaks are often more severe than the typical corrosion leak. A cracked main may leak at a high rate, quickly saturating the area around the break with natural gas, migrating and entering conduits and following the path of other utilities to homes or other confined spaces such as utility vaults and sewers.”
“Cast iron main breaks are of particular concern during periods of cold temperatures when frost actions may cause additional stresses on these mains and when frost caps create an impermeable barrier of the earth’s surface, preventing leaking gas from safely venting to the atmosphere.”
“Such leaks may be difficult to pinpoint as they can cause high gas readings at appreciable distances from the actual leak site. The difficulty of leak investigation is aggravated under frost conditions and with depth of frost penetration. The inability of the gas to safely escape increases the risk to nearby residents, as gas follows the path of least resistance, often to nearby habitable structures.”
This means that gas migrates through the soil to accumulate in cellars, crawl spaces, and basements, even in homes like mine without gas.
We do not have to continue to tolerate the risks to life and property and the waste of extending the life of deteriorating pipelines. In February 2023 City Councilors voted for the RESOLUTION FOR A FUTURE WITHOUT GAS AND FOR CLEAN HEAT. They acknowledged the urgency of reducing the enormous cost and risk of our gas infrastructure. It proposed criteria for creating a city-wide plan based on risk and cost analysis of the city’s gas pipelines so we can prioritize public safety and economic security and commit our resources to align with Newton’s and Massachusetts’ climate goals.
Please require National Grid to stop sinking resources into gas infrastructure and enable the Commonwealth to prioritize action based on a true standard of safety, reliability, and equity that gas pipelines can never achieve.
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