Massachusetts explosions: What happened?

Thursday’s deadly Massachusetts explosions have many people across the country wondering how such a thing could have happened.

Explosions were reported in the communities of Lawrence, Andover and North Andover, about 30 miles north of Boston. The Massachusetts State Police (MSP) said there were at least 70 reports of fires, explosions and gas odor.

“It looked like Armageddon,” Andover Fire Chief Michael Mansfield said. “There were billows of smoke coming from Lawrence behind me. I could see plumes of smoke in front of me. … It just looked like an absolute war zone.”

One person died and at least 13 were injured in the Massachusetts explosions. In Lawrence, 18-year-old Leonel Rondon was killed when a car in which he was sitting was hit by a falling chimney. He died at the hospital, authorities said.

Massachusetts explosions: billows of smoke

About 18,000 customers were without power, and at least 8,000 people could not return to their homes. A middle school in North Andover and a senior center in Andover were set up for evacuees, the MSP said.

“More than a dozen houses in North Andover went up in flames,” said resident Phil DeCologero, who commented that billows of black smoke were what first alerted him to the emergency.

“We’re a 30,000-person town, 27 square miles,” DeCologero said. “Given the number of fires, no municipality twice our size would be able to absorb that kind of catastrophe all at once.”

Massachusetts explosions: The towns of Lawrence, Andover and North Landover are approximately 30 miles north of Boston.

Massachusetts explosions: What happened?

The cause of the Massachusetts explosions was still unclear the morning after, but investigators theorized that the potential cause was over-pressurization of a gas main.

Before the explosions, Columbia Gas had notified customers it was “upgrading natural gas lines in neighborhoods across the state.” The company said the procedures would provide increased reliability and “enhanced safety features.”

What causes over-pressurized pipes?
According to earthsafe.com, the most common cause of over-pressure in piping is thermal expansion. That occurs when there is an increase in temperature of a pipe section that is blocked between two closed valves.

This happens because relatively cool fuel may be drawn from a tank into a higher temperature piping system. It can also occur because an exterior piping system may increase in temperature as the ambient temperature increases.

Thermal expansion of fluid will cause an increase in pressure that exceeds the pressure rating of pipe and valves in the system. That pressure must be relieved through safety relief valves installed in the piping system.

Relief valves should be installed in any piping section that could be blocked at both ends by closed valves. The safety relief valves should discharge to a return flow pipe or dedicated discharge pipe that is open to the fuel supply tank.

Some fuel system valves are available with internal pressure relief devices, however in general external relief devices are used.

The approximately 70 Massachusetts explosions north of Boston have left people across the United States wondering how such a thing could have happened.

Massachusetts explosions: NTSB inquiry

A spokesperson for the National Transportation Safety Board (NTSB) said the agency is sending a team to investigate, stating that pipelines are within the NTSB’s purview.

The agency will look at the design of the pipeline system, as well as maintenance and upgrades performed. The safety record of Columbia Gas also will be considered.

The NTSB’s job is not to lay blame, the spokesperson said, but to determine what exactly happened so the same situation can be prevented in the future.

Massachusetts explosions: “extended restoration”

A Columbia Gas spokesperson said the company expects “an extended restoration effort.” The utility is “working with the appropriate authorities to investigate this incident in order to understand its cause.”

To that end, Columbia Gas will visit each of the more than 8,500 affected customers to shut off each gas meter and conduct a safety inspection.