Tag Archives: AC Mitigation

Two of MATCOR’s products nominated for Corrosion Innovation Awards

Late last week, MATCOR received notification from NACE International two of its products were selected as nominations for the inaugural MP Reader’s Choice Corrosion Innovation of the Year Awards.

The two MATCOR products nominated were “The Mitigator” and MATCOR’s “Kynex” connection.  Here is a brief summary:

Kynex By MATCOR
Kynex Connection by MATCOR

Kynex is a unique injection molding technology used to connect a MMO/Ti wire anode to a positive anode header cable, providing a more robust connection than conventional connection technology.

The prior connection technology consisted of manually applied polyolefin heat shrinks as the outer layer—depending on the connection design employed, additional layers of sealants might be applied prior to the use of the heat shrink. These multi-step connections are all manually applied with little process control.

Kynex uses Kynar pellets injected at elevated temperatures and pressures into a mold around the anode wire and cable to provide an automated connection using the industries’ most chemically inert materials to provide a better connection.

The Mitigator
The Mitigator by MATCOR

The Mitigator is the pipeline industry’s first and only engineered gradient control wire packaged solution for AC Mitigation. Gradient control wires are the most commonly used technology for mitigating high levels of induced AC on pipelines in shared right of ways with overhead AC transmission lines.

Historically, pipeline companies would use either zinc ribbon or bare copper as a grounding wire running parallel to the pipeline. To improve the performance of the grounding wire, it is common to use a backfill material. The Mitigator provides a factory-packaged product that combines the copper wire with a special backfill packaged in an inert fabric housing ready to install.

To become this year’s recipient of the  MP Reader’s Choice Corrosion Innovation of the Year Awards we need your vote.

Follow this link, and scroll down to the online form…select Kynex as #1 and Mitigator as your #2 selection – then hit the submit button.  We would really appreciate your support.

If you are a LinkedIn, Twitter, or Facebook user and would like to be an Ambassador for MATCOR, please share this posting to your social media network.

Voting ends February 15, 2012.

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.