Category Archives: AC Mitigation

Manhattan Residents expressed fears for proposed 30-inch high pressure Natural Gas Pipeline

West Side residents expressed their fears at a Tuesday Community Board 2 forum about a proposed 30-inch, high-pressure, natural gas pipeline crossing the Hudson River from New Jersey to Gansevoort St.

The Spectra Energy pipeline between Linden, N.J., and the West Village has the support of the Bloomberg administration, which has mandated that thousands of residential furnaces using high-polluting No. 4 and No. 6 heating oil be converted in the next few years to relatively clean-burning natural gas.

Jason Mansfield, chairperson of the C.B. 2 Environmental, Public Health and Safety Committee, said the forum was intended to help draft the board’s response to the FERC review before the Oct. 31 deadline for public comment.

The federal agency is holding a meeting in Greenwich Village at P.S. 41, W. 11th St. at Sixth Ave., at 7 p.m. Thurs., Oct. 20, to take public testimony.

“This is an important meeting since your comments will be entered into the record and FERC can hear from you firsthand,” Mansfield said at opening of the Tuesday forum. The Oct. 4 pipeline forum was the committee’s third in two years.

Later this week the public will be able to file comments on the project directly with FERC online through the C.B. 2 Web site at www.CB2manhattan.org.

Representatives of Spectra Energy, Con Edison and the city Department of Environmental Protection spoke at length about the need for the pipeline and the safety measures to be employed in its construction and operation.

But opponents insisted they were not convinced that a new natural gas source was really needed, much less a large, high-pressure line with potential safety risks.

Regarding safety, one member of the audience demanded, “How can we trust you?” citing the Sept. 9, 2010, explosion and fire from Pacific Gas & Electric’s natural gas line that destroyed 53 homes, damaged 120 other buildings and killed one person in San Bruno, California, near San Francisco.

Spectra said the proposed pipeline would have specially made and inspected high-strength flexible pipe with coating inside and out, buried 3 feet or more with special fill. In operation, technicians monitoring operations via robotics could remotely shut down the line.

But C.B. 2 members noted that the board last year suggested that automatic shutoff valves might be more reliable than remote control shutoff. However, Spectra representatives at the Tuesday forum said technology for remote shutoff was better than automatic shutoff technology.

“A lightning strike could trigger an automatic shutoff,” said Ed Gonzales, Spectra project manager.

The Spectra pipeline under review would cross the southwest corner of Gansevoort Peninsula, cross the West Side Highway at Gansevoort St. and terminate on the west side of the proposed Whitney Museum property.

Con Edison would build its own high-pressure, 30-inch, natural gas line from the Gansevoort terminus of the Spectra pipeline along 10th Ave. for 1,500 feet to a Con Edison connection at 15th St. at 10th Ave.

But the Con Edison connector line is not part of the FERC environmental review. Cheryl Payne, the engineer in charge of Con Edison’s gas transmission, said the connector line has not been designed yet. But she said the materials and construction method would conform to the same high standards of the Spectra pipeline.

The Con Edison connector line would also use a remote shutoff system. Like the Spectra representative, Payne said an automatic shutoff system could be triggered by an event like lightning and needlessly leave large areas of the city without service.

C.B. 2’s Mansfield said later that the environmental review of the Spectra project should include Con Edison’s connector line.

“I don’t think they really made the case that the pipeline is needed,” he added. “It just wasn’t justified in view of its potential for catastrophic damage.”

Many of the project’s opponents at the Tuesday meeting had in mind the impending rules on natural gas production by high-volume hydrofracture drilling in New York State’s Southern Tier.

Spectra representatives said the company’s business was only natural gas transportation, not production. Indeed, the draft environmental impact statement indicates that the pipeline would be able to bring natural gas from the Marcellus Shale regions of southern New York and northern Pennsylvania into the Manhattan.

Catherine Skopic, an environmental advocate, told the Oct. 4 forum that it was time for investment and exploration of renewable resources like solar voltaic cells and wind energy instead off fossil fuel.

Opponents were also skeptical about the common assumption that natural gas is the cleanest of fossil fuels, if the environmental damage of hydrofracture drilling is included in the assumption.

Speaking to the fear of terrorism, Frank Eady, a former member of Community Board 4, raised the specter of Stuxnet, a computer program that he said was used to sabotage and set back Iran’s nuclear weapons program.

“That program is out there,” he warned.

Spectra representatives acknowledged that they didn’t know about Stuxnet, but Gonzales said the company monitored potential cyberspace danger.

Mav Moorhead, a Lower Manhattan resident angrily demanded, “Who will be accountable when the neighborhood blows up?” she said, adding, “We don’t have a hospital,” referring to the closing of St. Vincent’s.

SOURCE: http://www.thevillager.com/villager_441/gaspipeline.html

Search for gas leaks in Seattle cut short before blast

Puget Sound Energy says electrical arcing caused by a fallen tree created holes in natural-gas pipes, leading to an explosion at a North Seattle house.

After a rare electrical problem blew four holes in natural-gas pipes in Seattle’s Pinehurst neighborhood on Sunday, Puget Sound Energy says, the agency went house to house in the neighborhood to check for more leaks. Its workers stopped at nightfall, without finding more.

It wasn’t until the next day, after a huge explosion and house fire, that PSE did a much larger “leak survey” across a 5-square-mile area, working into the night. Crews found four more leaks, but say at least three are unrelated.

With customers and Seattle residents rattled Tuesday, PSE defended its initial search. Sunday’s testing area — which stopped just blocks short of the explosion site — focused on areas with similar pipe, said Martha Monfried, PSE’s communications director.

She said it would not have been safe to continue the leak survey into the night. “You can’t do residential survey work in the dark, for both worker safety and for the comfort level of homeowners,” she said.

But Mark McDonald, a natural-gas expert who speaks about catastrophic leaks, said PSE should have gone farther.

“I would go at least 10 blocks in every direction to make sure we got all the leaks,” said McDonald, president of the New England Gas Association, an umbrella group of unionized utility workers. “Night, storm, whatever, you go farther than you need to be safe. It obviously was a mistake.”

Storm blamed for “arcing”

The source of the leaks, according to the utility, originated during a windstorm Sunday.

At about 11:30 a.m., a tree came in contact with one of the three overhead electrical distribution lines on Northeast 127th Street between 12th Avenue Northeast and 10th Avenue Northeast, said Seattle City Light spokesman Scott Thomsen. The incident tripped the breakers and the circuit quickly shut off.

“Our equipment’s role is to ground out that short, and the system operated the way it’s designed to operate,” said Thomsen.

According to PSE, the electrical current, conducted through the tree, energized a wrapped steel natural-gas pipe, causing a problem known as “arcing.” The current blew a series of BB- or finger-sized holes in the pipe, according to the utility.

On Tuesday, PSE said the supply pipe and gas meter found at the blast site showed a hole just inches outside the Ingham home, at 12312 Fifth Ave. N.E., about seven blocks from where the power tripped Sunday.

The natural-gas service line to their home was pressurized at 45 pounds per square inch, according to PSE. It won’t be clear until an investigation is completed how the gas got into the home, but experts theorized that the gas could have leaked in through a foundation.

Seattle Fire Department spokesman Kyle Moore confirmed that investigators determined there was an accumulation of gas inside the house. But it wasn’t clear if the buildup was from the leak outside the house or from a second leak that might have occurred inside, he said.

Two engineers from the state Utilities and Transportation Commission (UTC) are investigating Monday’s fire and explosion, as well as PSE’s response to Sunday’s gas leaks.

Dave Lykken, pipeline safety director for the commission, said the neighborhood’s natural-gas pipes are probably 1960s-vintage — with some new plastic pipe — and are considered safe.

UTC requires utilities to routinely check natural-gas pipelines for corrosion. PSE said it conducts neighborhood leak surveys every three years; it last checked the Pinehurst area in November 2008, said Andy Wappler, a PSE spokesman.

In the more exhaustive survey ordered after the explosion, PSE found four new leaks, but said at least three were unrelated and characterized them as small enough that they would be treated as scheduled — rather than emergency — repairs in a different situation. The other leak remains under investigation.

A third survey began Tuesday, and a fourth is planned.

SOURCE: http://seattletimes.nwsource.com/html/localnews/2016332869_gasleak28m.html

Zinc Ribbon or Copper for AC Mitigation – that is the question…

Team members of MATCOR have been involved in several online discussions (LinkedIn) about the pros and cons of Zinc Ribbon for use in AC Mitigation. So we thought we would share our expertise in this subject on our blog.

Below are 4 reasons why we believe Copper (and our AC Mitigation product, “The Mitigator“) is a superior solution to Zinc Ribbon.

  • Formation of passive films on the surface of the zinc can cause a significant electropositive shift in the zinc potential over a period of time; this generally occurs over a period of days or weeks. The general rule of thumb is that the concentration of chlorides and sulfates must be measurably greater than the sum of the concentrations of bicarbonates, carbonates, nitrates and phosphates; otherwise with time the zinc corrosion potential will shift electropositive. Plattline’s Web site notes that zinc ribbon is “generally used with gypsum backfill”; however, too often for AC Mitigation applications, no consideration is given to placing the zinc ribbon in a specially prepared backfill (this should be general practice).
  • Zinc faces high consumption/corrosion rates in the presence of AC. A.W. Peabody has noted that AC can “create an especially high corrosion rate with buried aluminum, magnesium and zinc”. Testing of zinc electrodes at an AC Current density of 155 A/m2 found a 15-20 fold increase in the consumption rate of zinc. R.A. Gummow, a corrosion engineer and a NACE International accredited Corrosion Specialist, notes that “accelerated corrosion of zinc ribbon AC mitigation facilities must be expected and needs to be accounted for in the cathodic protection design despite the lack of information on the magnitude of the accelerating effect”.
  • The effect on existing impressed current CP systems: the use of zinc anodes directly connected to the pipeline for AC mitigation can interfere with existing impressed current CP systems in a way that is both difficult to model and to predict. In some cases, the zinc anodes can become an additional load, particularly if the zinc is not located in a prepared backfill and has shifted to a more electropositive potential. In other cases, the zinc anode may be providing and/or supplementing galvanic current to the CP system in which case it will be consumed over time – note that the presence of AC often increases significantly the consumption rate. This could result in premature consumption of the zinc ribbon as an AC Mitigation system.
  • The effect of the zinc ribbon on potential surveys when directly connected to the pipeline can be erratic and difficult to interpret, rendering these surveys inconclusive or invalid. Given the emphasis on integrity management and the additional risks posed by AC Induced Corrosion in collocated right-of-way (ROW) corridors, the negative impact that the zinc ribbon might have on survey data could make CIS surveys invalid and increase the need for and frequency of Inline Inspections (ILI).

In addition to these 4 key reasons, MATCOR’s ‘The Mitigator‘ is the pipeline industry’s first engineered AC Mitigation grounded system, with greater ease of installation and lower overall cost.