The hidden dangers of corrosion under insulation (CUI) span the oil and gas industry from upstream operations to midstream infrastructure and downstream applications, including the production of LNG. CUI is a severe form of localized corrosion that occurs when water, inorganic salts, and other contaminants become trapped beneath insulation covering pipes, valves, tanks, and other assets, leading to the formation of corrosion cells that are hidden from view and can spread unnoticed.
In oil and gas operations, elevated process temperatures may accelerate corrosion rates, leading to pitting and metal loss that may cause leaks and potentially catastrophic failures, with the potential to harm personnel and, in extreme cases, cause the loss of life.
Yet, in LNG operations, cold/cryogenic temperatures can also contribute to increased CUI risks. A perfect recipe for corrosion – moisture, oxygen, and chlorides – exists in both temperature scenarios, but moisture from condensation can be especially prevalent under insulation in cryogenic LNG operations due to the extreme temperature differentials with ambient air. Studies show that moisture causes 85% of insulation system failures in LNG operations. At the same time, some LNG applications also operate at high heat, compounding CUI threats across entire facilities.
Radiographic Testing (RT) is a bit like taking an X-ray of a material or object to see inside it. Imagine you’ve seen doctors use X-rays to look at bones inside our body. RT does something similar, but it’s used for things like pipelines, pressure vessels, airplane parts even bridges, but not people.
Here’s how it works:
X-rays or Gamma Rays: Just like in a medical X-ray, RT uses special kinds of light called X-rays or gamma rays. These rays are very powerful and can pass through objects, unlike regular light.
Film or Detector: On the other side of the object, there’s a film or a digital detector. When the rays pass through the object and hit this film or detector, they create an image.
Looking Inside: Different parts of the object let different amounts of rays pass through. So, the image shows a kind of shadow picture of what’s inside. It can show if there are any cracks, holes, or other problems that we can’t see from the outside.
Safety First: RT uses high-energy rays that can be harmful, so it’s important to do it safely. Only trained professionals should do Radiographic Testing, and they use special equipment to protect themselves and others.
Bottom line: Radiographic Testing is a powerful way to look inside objects and materials to find problems without having to cut them open.
Nondestructive Testing (NDT) Plugs are engineered to allow repeat access for EPA/OSHA inspection and process safety management.
Plugs can be installed on insulated and non-insulated pipe, storage tanks, pressure vessels and petrochemical, oil and gas, steam and nuclear power generation facilities.
Engineered NDT2 inspection plugs consist of an elastomer sleeve, metal handle, metal cap, lanyard* and locking ring.
The elastomer sleeve consists of ethylene propylene (EPDM) or silicone (higher temps).
The metal caps can be 304 stainless steel or 5052 aluminum depending on the application.
* Note: lanyards are particularly useful in overhead conditions to prevent the cap from falling if dropped.
Regular access to pipes and equipment benefits areas of process safety management:
Safety NDT inspection plugs allow inspectors to safely access the inside of insulated pipes and equipment without removing the insulation. This helps to ensure the safety of the piping system.
Accuracy NDT inspection plugs help to ensure that thickness measurements are accurate. They also standardize the location of thickness measurements, which helps to protect the integrity of inspection data.
Time NDT inspection plugs reduce the time required for periodic inspections and tests. Once installed, access often.
Corrosion NDT inspection plugs provide a seal that can help protect against corrosion under insulation (CUI), chemical and UV exposure.
Stainless steel and aluminum are popular materials for NDT inspection plugs due to their specific properties that make them suitable for harsh environments.
Stainless Steel Plugs
Durability: Stainless steel is known for its high strength and durability, which makes it ideal for use in environments that experience high stress or mechanical wear.
Corrosion Resistance: It offers excellent resistance to corrosion, particularly from chemicals and moisture, making it suitable for applications in chemical plants, marine environments, and other areas where corrosion is a concern.
Temperature Resistance: Stainless steel can withstand extreme temperatures, both high and low, without losing its structural integrity, which is essential for various industrial applications.
Aluminum Plugs
Lightweight: Aluminum is significantly lighter than stainless steel, which makes it easier to handle and install, especially in applications where weight is a critical factor.
Corrosion Resistance: While not as corrosion-resistant as stainless steel, aluminum still offers good resistance to corrosion, particularly when it is anodized or coated, which makes it suitable for many industrial environments.
Conductivity: Aluminum has good thermal and electrical conductivity, which can be beneficial in certain NDT applications where these properties are required.
