Linc Energy Blog

It is no secret that the effectiveness of your cathodic protection system depends on the experience of the installer and the quality of raw materials put into the pipeline. Many CP professionals often wonder about the pros and cons of using insulating flange kits over monolithic isolation joints.

The monolithic insulating joint was developed as an alternative to insulating flange kits. It has been widely used in Middle Eastern and European countries in the Oil & Gas Industry. While they have been used in the United States, their benefits have been overshadowed by long lead times from European manufacturers.

Now with the expansion of a United States insulating joint manufacturer, I wonder if the use of insulating joints will give insulating flange kits a run for its money.

What are the pros and cons of using monolithic insulating joints versus insulating flange kits?
 

Disadvantages of insultating joints

The primary disadvantage of using monolithic insulating joints in U.S. pipelines has been the long lead times from European manufacturers. While some U.S. distributors have tried to appease the availability issue it has become a challenge for contractors to work with staggering lead times when inventory has been depleted.

The often perceived secondary disadvantage is the upfront expense of an insulating joint which can be twice the cost of an insulating flange kit.

Advantages of Monollithic Isolation

Barlow Insulating Joints  ~ Now offering stock availability in most sizes

Insulating joints come preassembled and pretested versus the traditional insulating flange kit, which requires a skilled technician to assemble it on site. By using the Insulating joint the company saves on site labor. The joints are also less likely to fail from improper installation which could render a CP system ineffective and likely result in both internal and external corrosion.

With an insulating joint, serviceability and maintenance is simplified. Whereas, when using an insulating flange kit the system may become shorted when buried (from settling, thermal expansion or over-tightening). In this case, the cost to repair a damaged or leaking system significantly exceeds the initial investment of an insulating joint. It is also more likely that the pipeline would have to be shut down if maintenance or replacement is required.

When evaluating the advantages and disadvantages of using insulated flange kits versus monolithic insulating joints it would seem that when life cycle costs are considered, the use of monolithic insulting joints is advantageous over the flange kits.

New U.S. Insulating Joint Manufacturer

With the recent rash of gas pipeline explosions, of which many believe are corrosion-related, the spotlight is on gas pipelines to increase safety and quality of pipeline materials and testing. The expansion of Barlow Insulating Joints, a U.S. manufacturer seems timely. Barlow apparently is not new to the industry, and has manufactured insulating joints for over 50 years serving the east coast. The company was acquired by IMAC Systems a couple years back who has decided to expand the Barlow line to the west coast.

Perhaps the availability of U.S. monolithic insulating joints will impact the way U.S. pipelines choose their insulating methods.
 

Tags: CP, corrosion control, gas explosion, monolithic, insulating joints, isolation, cathodic protection

Over the years I’ve been amused with the variety of responses I’ve received when I’ve asked, “What is cathodic protection?” If I’m talking to a corrosion engineer I get one answer, if I’m conversing with an operations person I get something different. I thought, ‘Here’s a challenge - let’s describe cathodic protection in a way a layperson would understand.’

Cathodic protection (CP) is a technique used to control the corrosion of a metal substance in various applications. Some common areas which apply this science are: fuel tanks, pier pilings, ships, offshore oil platforms and casings, metal reinforcement bars for concrete structures, as well as pipelines.

To simplify cathodic protection – assume you have a metal pipeline and you need to protect it against corrosion. Pipelines are generally supplemented with CP after being protected with an anticorrosion system (coating or wrap) as the primary form of corrosion protection. Otherwise the cathodic protection required to combat corrosion for an uncoated pipeline is excessive.

The first step in cathodic protection is to take the metal you are trying to protect (pipeline) and turn it into a cathode. A pipeline is normally anodic, it contains positively charged electrons. By supplying an electric current the pipeline becomes passive or cathodic. The science reveals that as long as the electron current is arriving at the cathode (pipeline) faster than oxygen is, then corrosion will be prevented or significantly slowed.

Pipelines commonly use Impressed Current Cathodic Protection (ICCP) which uses a rectifier along with anodes buried in the ground. The rectifier (a DC power source) supplies electrons to the system stopping corrosion of the pipeline and since the anodes don’t surrender many electrons they don’t corrode much either.

Sometimes it’s more economical to use a galvanic anode system in which the anodes (Magnesium, Zinc or Aluminum) are the electron source and are sacrificed and corrode over the steel pipeline.

The video below offers a simple representation of ICCP.  

I hope you enjoyed this back to basics session on “What is cathodic protection?”
 

Photo: http://140.194.76.129/publications/eng-manuals/em1110-1-4008/c-12.pdf

 

Tags: CP, ICCP, damage prevention, cathodic protection, corrosion control

The subject of pipeline corrosion is all over the news these days. Perhaps the San Bruno explosion in September has heightened my senses to the issue, or perhaps pipeline corrosion is getting its fair share of ink in the press. Just last Friday I learned that there was an incident related to pipeline corrosion in Provo, Utah. At an apartment complex, some residents had been without heat or hot water for over a week because the gas line was shut off because of pipeline corrosion. The line is almost 40 years old.

Can you imagine a week without hot water and heat? What an inconvenience that must have been for the occupants … but how fortunate the situation did not escalate to an incident like the one in San Bruno.

Successful methods to prevent corrosion in pipelines

Unprotected pipelines corrode, no matter where the pipeline is. If it’s buried underground, above ground or in water, it’s going to deteriorate. As 60% of our nation’s transmission lines approach their life expectancy of a half century, we’re hearing more and more about pipeline failures. This should not be a surprise. Without implementing safety measures and having a corrosion control program, corrosion makes transporting hazardous material unsafe.

A successful corrosion control program is a never ending practice. It begins with an effective design and installation of the pipeline, executing corrosion control methods, and maintaining and monitoring the lines. Here are some of the methods NACE (National Association of Corrosion Engineers) recommends as part of a successful corrosion control program to protect oil and gas pipelines. With the exception of the last method, three of the four can be used on existing pipelines.

 

• Cathodic protection (CP) is a method to control corrosion by using a direct electrical current which neutralizes external corrosion typically associated with metal pipe. It is generally used when a pipeline is buried underground or in water. When executed on a new pipeline, cathodic protection can prevent corrosion from the start. On an older pipeline, cathodic protection can impede existing corrosion of the line.

• Coatings and linings are applied to pipelines whether above or below ground and often are used in combination with cathodic protection. (To the right a section of 16” pipe reconditioned with Trenton #1 Wax-Tape and Glas-Wrap. Picture courtesy of Trenton Corporation.)

Another application that is currently getting some attention is the use of fiber-reinforced polymers to strengthen and repair pipelines.

• Corrosion inhibitors are compounds which when added to the upstream pipeline can inhibit the corrosion of carbon and low-alloy steels which are commonly used because of their cost effectiveness.

• Pipeline material used will also significantly influence corrosion. Using materials like plastic, stainless steel or special alloys can enhance the lifetime of the pipeline, while steel or steel reinforced concrete is subject to corrosion.

While the nationwide corrosion issue may seem a bit daunting, I thought it was a good time to discuss some technology we currently have which can indefinitely extend the structural life of our pipelines.

 

Tags: corrosion inhibitors, cathodic protection, repair pipelines, trenton corporation, wax-tape, NACE, anti-corrosion, fiber reinforced polymers, FRP, corrosion prevention

In the wake of the San Bruno gas line explosion, two California senators filed legislation yesterday to increase the regulation of our nation’s pipelines.

Utility companies have been under pressure for years to increase their inspections and replacement of aging pipelines. The San Bruno explosion, resulting in seven fatalities (as of 9/22/10) and leveling nearly 40 homes (destroying over 50), has cranked up the heat even more.

In 2000, a gas pipeline exploded and killed 12 people near Carlsbad, New Mexico. In that explosion, the pipeline was also an aging one, dating back to 1950 and was investigated by the National Transportation Safety Board (NTSB). The cause of the rupture was determined to be from severe internal pipe corrosion.

Since the San Bruno explosion, reports have surfaced that aging pipelines are a threat to gas pipelines nationwide. The concern has been raised that more than 60% of this country’s transmission lines are over 40 years old and the life expectancy is around 50 years. The majority of these lines are made of steel which is prone to corrosion and many of the pipelines were installed before suburbs emerged, and now present the risk that they could leak or erupt … beneath now populated suburban neighborhoods.

In 2002, a law was passed by congress which required utilities to inspect pipelines that run through densely populated areas. While critics suggest that utility companies don’t want to spend money to inspect and repair aging pipelines, over 3000 problems were identified during the first five years of this legislation. This demonstrates that the regulation has identified and resolved precarious situations, but it also clearly reveals just how unstable our aging pipelines are.

Yesterday, Senator Dianne Feinstein and Senator Barbara Boxer introduced new legislation which would increase regulation of our nation’s pipelines.

“The pipeline explosion in San Bruno was a tragedy that must never occur again in any American neighborhood,” Senator Feinstein stresses in a statement. “That’s why today we are introducing legislation specifically designed to improve pipeline safety – and to establish penalties for violators.

“The American people must be assured that the pipelines that crisscross the nation and run beneath their streets are safe. This legislation is a strong first step in that direction.”

The Strengthening Pipeline Safety and Enforcement Act of 2010 expands on Ray LaHood U.S. Transportation Secretary’s legislation which was proposed last week, and would^(1):
 

• Double the number of federal pipeline inspectors (there are currently 100 inspectors each responsible for inspecting over 2,000 miles)
• Require the use of electronic shut off valves to cut off gas in an emergency rather than manual valves which need to be located and manually turned off
• Order the internal inspection of pipelines by robotic devices, “smart pigs,” or other methods which are deemed equally successful
• Prohibit pipelines from working at high pressure if the line cannot be inspected using effective assessment methods
• Priority will be given to aged pipelines in seismic areas

The legislation, being authored by the two California senators is calling for an increase in penalties for violators of the federal safety regulations. It’s unclear when this legislation will be put to a vote, though we are sure to hear more in the weeks to come.
 

 

 To the left, utility safety worker inspects pipeline and valve wrapped with Trenton Wax Tape for cathodic protection.

 

 

 ⁽¹⁾ California Senators call for tougher pipeline standards

 

Tags: natural gas, damage prevention, San Bruno explosion, gas line rupture, corrosion prevention, cathodic protection, Trenton wax tape, pipeline regulation, Strengthening Pipeline Safety and Enforcement Act