Category Archives: Infrastructure

The New Pipeline Rule I Waited Half a Career to See

By Charles Koval

One night, a couple feet underground outside an American home, the gas flowing in a service line began to escape through a puncture adjacent to a newly installed mailbox. A man and woman inside the home were watching the news. Their children were playing. Then, suddenly, without warning . . . nothing happened.

A simple and inexpensive device called an excess flow valve (EFV) kicked in, stopping the gas flow. There was no explosion, no fire, no injury or loss of life.

As a petroleum engineer and pipeline specialist for the NTSB, I know that the most important pipeline safety advance in recent decades has been the establishment of the national one-call 811 number. But EFVs may be the next most important life-saver, especially for homeowners.

Diagram of how an excess flow valve functionsGas companies install an EFV in a service pipeline where it meets the main line. The EFV shuts off the gas flow in the service line when it exceeds the normal flow rate; excess flow often indicates that gas is escaping the service line through a puncture or sever, potentially leading to an explosion or fire.

I’ve been working a long time to encourage the progress that came to fruition late last year regarding EFVs. The Pipeline and Hazardous Materials Safety Administration (PHMSA) quietly completed an important achievement and, in the process, closed an NTSB recommendation. PHMSA issued a rule expanding the use of EFVs to new or renewed service lines leading to almost all small commercial businesses and multi-residence buildings.

It’s taken decades to achieve this result. In all, the NTSB has made 24 safety recommendations related to EFVs.

When I came to the NTSB in 1990, the agency had already been endorsing EFVs for 20 years, beginning with recommending a shutoff valve after research that came out of a 1970 safety study.

I worked on accident after accident that may have been prevented by EFVs. Most of my work between 1990 and 1994 involved single-family residences, but many multi-residence accidents were just as horrible, if not worse. The incidents occurred in large cities like Tulsa, Oklahoma, and St. Paul, Minnesota, and in smaller towns like St. Cloud, Minnesota; Montezuma, Indiana; and Cliffwood Beach, New Jersey. I can still remember my first NTSB supervisor expressing exasperation that this simple and elegant solution was not in wider use.

Then came June 9, 1994. At about 6:45 that evening, a 2-inch-diameter steel gas service line that had been exposed during excavation separated at a compression coupling about 5 feet from the north wall of John T. Gross Towers, an 8-story retirement home. The escaping gas flowed underground toward Gross Towers, passed through openings in the building foundation, entered the mechanical room through the floor vents, and migrated to other floors.

A resident smelled the gas, as did a workman onsite, who told his foreman. The foreman called the gas company and the housing authority, then had other employees locate and shut off the gas line valve inside the towers. But at 6:58 p.m., the built-up natural gas in the building ignited and exploded; a second explosion followed 5 minutes later. The accident killed one person and injured 66—and it could have been much worse. Many residents were not in the building on the early summer evening of the disaster.

A humble EFV could have shut off the gas flow into Gross Towers. After the explosion, the NTSB recommended that PHMSA’s predecessor agency require that all gas distribution operators inform all customers of the availability of EFVs. After many years, the agency did so. Meanwhile, fatal accidents continued—all potentially preventable with EFVs.

Then, in 1998, the NTSB was called to the site of an explosion and fire at a single-family home in South Riding, Virginia.

A man, woman, and their two children were spending their first night together in their new home. The family retired at about 10:30—the children to the upper level of the house, and, because not all of their furniture had arrived, the parents to the first-floor study. Shortly after midnight, the house exploded and was engulfed in flames. The children were thrown out of the house and onto the lawn, suffering minor injuries. The parents fell into the basement as the first floor collapsed. The father was able to crawl to safety, badly burned; the mother did not escape and died as a result of her injuries.

Again, an EFV could have prevented the tragedy.

Following this accident, the NTSB recommended that PHMSA require EFVs in all new and renewed gas service lines, regardless of customer classification, when operating conditions were compatible with readily available valves. PHMSA first required only that single-family homeowners be notified of the availability of the valve and be allowed to pay for it themselves. Then, in 2009, PHMSA changed the rule, requiring EFVs to be installed on almost all new and renewed service pipelines to single family homes.[1] Finally, on October 14, 2016, PHMSA expanded the safety requirement to include most new and renewed service pipelines for multi-residential and commercial applications, closing one chapter in EFV history—and with it, an outstanding NTSB recommendation.

My first NTSB supervisor is no longer with us, but even years ago, he could imagine the broad use of EFVs that he did not live to see. Sometimes it takes a long time to normalize safety. Too often, it takes a highly visible accident—or several of them—to draw attention to a problem. Solutions often come a little bit at a time, or a long time afterward, without any fanfare.

But for now, and well into the future, for many businesses and homes nationwide, if a service line fails, nothing will happen. These homes and businesses are a little safer today because PHMSA and the gas industry acted on NTSB’s EFV recommendations.


Charles Koval is a Petroleum Engineer and Pipeline Specialist in the NTSB Office of Railroad, Pipeline and Hazardous Materials.


[1] The service line does not need an EFV if it: 1. does not operate at or above 10 psig all year, 2. has previously had contaminates, 3. could interfere with necessary operation or maintenance activities, or 4. is not commercially available to the operator.

Twelve Accidents in Twelve Days: NTSB Investigators on the Scene

By Debbie Hersman

In just under two weeks there have been four major accident launches. On Friday, May 17, the NTSB launched a go-team to Bridgeport, Conn., to investigate a derailment and collision involving two Metro North passenger trains. The following Friday evening, a bridge collapsed over the Skagit River in Mt. Vernon, Washington; the NTSB was on scene that evening and the rest of the go-team arrived the next morning. Then, early in the morning on May 25, two freight trains collided under a highway overpass in Chaffee, Mo., causing the trains to derail and the overpass to partially collapse. Another go-team launched and arrived in Missouri that afternoon. Next, on May 28 a train struck a truck at a railroad grade crossing near Baltimore, Maryland; and yes, another go-team launched.

Skagit River bridge collapse in Mt. Vernon, Wash.
Skagit River bridge collapse in Mt. Vernon, Wash.

And, while go-teams were launching all over the country, other investigators were responding to additional accidents. On May 20, there was a fish processing vessel fire near Seattle and a marine safety investigator traveled to Washington to work with the U.S. Coast Guard. Similarly, two marine safety investigators traveled to Freeport, Bahamas, to join the Bahamian authorities and the Coast Guard in the investigation of the May 27 Grandeur of the Seas cruise-ship fire. On May 28, a Metro North passenger train struck and killed a track foreman in West Haven, Conn.; NTSB sent an investigator to West Haven this morning.

During this same period, NTSB regional aviation safety investigators responded to fatal accidents in Auburn, Ca. (May 18); Garoga, N.Y. (May 24); Cross Timbers, Mo. (May 25); Macon, Ga. (May 27); and Flagstaff, Ariz. (May 28).

Investigator Ted Turpin documenting damage at the scene of the rail grade crossing collision in White Marsh, Md.
Investigator Ted Turpin documenting damage at the scene of the rail grade crossing collision in White Marsh, Md.

The total: 12 accidents in 12 days. There’s a lot going on and our dedicated professionals are up to the challenge. In each of these investigations, the goal is simple: find out what happened and why so that we can develop safety recommendations to prevent future accidents and needless loss of life and injuries.

America’s House – Fix it First

Pacific Coast HighwayBy Debbie Hersman

Our transportation infrastructure—roads, railways, waterways, and airports— is what makes the movement of people and goods possible; it drives our economy. In a way, our infrastructure is like a house – America’s house. It needs to be maintained for ourselves and generations to come. In his State of the Union address, President Obama proposed a “fix-it-first” approach to investing in our nation’s deteriorating infrastructure. And the NTSB believes that as these investment decisions are made, safety needs to have a seat at the table.

The “Fix it First” plan makes repairing and upgrading existing roads, bridges and public transportation systems a priority over spending on new projects. In 2006, 70,000 of the roughly 600,000 bridges nationwide were classified as “structurally deficient,” meaning that major deterioration, cracks or other flaws reduced its ability to support vehicles.

Back in 2006, the I35W bridge in Minneapolis was identified as a structurally deficient bridge. Before improvements could be made, that bridge collapsed on August 1, 2007, killing 13 people and injuring another 145. In our subsequent investigation of this tragedy, the NTSB identified three critical factors that contributed to this collapse: (1) a failure in the design firm’s quality control procedures to ensure that all calculations were performed correctly, (2) inadequate design review by Federal and State transportation officials, and (3) inadequate attention to a critical bridge component during inspections.

For information on NTSB’s accident investigations and recommendations to better invest in and allocate resources that will preserve the integrity of American’s transportation infrastructure, visit the NTSB Most Wanted List Preserve the Integrity of our Transportation Infrastructure webpage.

In “Fix It First, Expand It Second, Reward It Third: A New Strategy for America’s Highways,” a report by The Hamilton Project at the Brookings Institution, authors Matthew Kahn and David Levinson argue that the roads and bridges that make up our nation’s highway infrastructure are in disrepair as a result of insufficient maintenance — a deficit that increases travel times, damages vehicles, and can lead to accidents that cause injuries or even fatalities. This report emphasizes that if we want to prevent future tragedies, such as the I35W bridge collapse, we need to make effective investments that put safety at the center.

How Are You Recognizing Critical Infrastructure Protection and Resilience Month?

By Debbie Hersman

Damaged bridge rural America FEMA

This is Critical Infrastructure Protection and Resilience Month. This December, President Obama has called Americans across the country to maintain our commitment to keeping our critical infrastructure and our communities safe and resilient. In his proclamation, the President reminded us that, “Our Nation’s critical infrastructure is complex and interconnected, and we must understand not only its strengths, but also its vulnerabilities to emerging threats.”

At the NTSB, we focus on one part of that infrastructure – transportation. Every day, Americans rely on transportation infrastructure to take children to school, travel to work, take vacations and to obtain daily necessities, including food, clothing and energy. We know firsthand how important our transportation infrastructure can be to families and communities, as so many of our fellow citizens experienced in New Jersey and New York after the devastating effects of Super Storm Sandy.

The absolute importance of transportation to our economy and quality of life is why preserve the integrity of our transportation infrastructure is on the NTSB’s Most Wanted List.

What should be done to preserve our transportation infrastructure? Our accident investigations have revealed that inspection guidance that incorporates all elements of the structure, proper maintenance and use of available technologies all have a role to play. Perhaps the most important thing to remember is that whenever decisions are being made about infrastructure, safety must have a seat at the table.

Here’s a snapshot of the scope of our nation’s infrastructure:  In 2010, 4.2 trillion passenger miles were traveled on our nation’s roadways. Domestic freight traffic carried by air, truck, rail, water and pipeline totaled more than 4.3 trillion ton-miles. That means there are literally trillions of reasons to maintain the integrity of our roads, runways, waterways, rails and pipelines.