This week, we will look at some of the different types of mechanical integrity inspections that are available, and what they are used for.
API inspections are performed by inspectors holding certifications from the American Petroleum Institute (API). API inspections cover tanks, piping, and pressure vessels. There are many certification programs available, but some of the most common are API 510 (pressure vessels), API 570, (piping), and API 653 (above-ground storage tanks).
Steel Tank Institute (STI) inspections apply to above-ground tanks. This includes shop-fabricated tanks, field-erected tanks and portable containers. The STI SP001 standard provides a means for tank owners to comply with EPA mandates. It applies more applicable inspection guidelines for smaller capacity storage tanks.
Pennsylvania DEP tank inspections are required for certain tanks located in Pennsylvania. These include above-ground storage tanks greater than 5,000 gallons, and highly hazardous substance tanks greater than 1,100 gallons. The tanks are required to be registered with the state and inspected by state certified inspectors.
NACE CIP (Coatings Inspector Program) inspections are used to examine protective coatings. This ensures that the equipment being coated is prepared correctly and the coatings are applied as per the manufactures specifications to maximize the life and effectiveness of the coating system. Structures that may require coating inspection include tanks, piping, vessels, towers, and bridges.
Certified weld inspections examine the quality of welds on tanks, vessels, and other structures. The welding inspector will determine if the welders are using an appropriate welding procedure and that they are qualified to weld to that procedure. The inspector would ensure that the welding variables stay with established tolerances such as amperage, voltage, travel speed, shielding gas, pre heat temperature, etc. Poor weld quality can limit the life of a piece of equipment and lead to failures, possible loss of containment and in some cases catastrophic failure.
The New York State Department of Environmental Conservation (NYS DEC) requires the inspection of chemical bulk storage and petroleum bulk storage containers. This applies to both aboveground and underground tanks. The state has a specific set of criteria not only for the storage tank but also for the system. The inspector will evaluate the tank, the secondary containment, the associated piping system, the pump system, the relief system, that proper labeling is in place and more.
Ground penetrating radar (GPR) uses radar pulses to determine if there are objects located under the surface. It can be used on dirt, stone, concrete, wood, and other materials. An object of a different density in the ground or in concrete acts as a reflector and returns a different signal that its surroundings. In addition to detecting hidden objects, such as tanks and pipes, GPR can show changes in material, voids, cracks, and the thickness of walls, floors, slabs, and other layers.
Magnetic particle testing detects discontinuities on and just below the surface of materials such as iron, nickel, and cobalt. The method uses the physical property of magnetic flux to identify issues with a material. A magnetic field is induced in the part to be examined and any indications in the part are identified by the use of magnetic particles which will group up at the defect due to the change in the magnetic flus that it causes.
Liquid penetrant testing (also referred to as dye penetrant inspection) is used to identify surface-breaking defects in non-porous materials. It can detect casting, forging, and welding defects such as cracks, surface porosity, and leaks.
Ultrasonic thickness testing is a method of gauging the thickness of something, typically made of metal, based on the time taken by the ultrasound wave to return to the surface. In this way, areas of deterioration or pitting can be identified.
Magnetic flux leakage is commonly used in pipelines and storage tanks to detect corrosion and pitting. The damaged area can be identified, and the depth of metal loss can be estimated.
Leak testing encompasses several methods of detecting, locating, and measuring leaks which have occurred in vessels, pipelines, or their components. The most common methods include bubble leak testing, halogen diode testing, pressure change testing, and mass spectrometer testing.
Positive material identification is the analysis of a metallic alloy to establish its composition. This is done by reading the quantities by percentage of its constituent elements using methods such as x-ray fluorescence and optical emission spectrometry.
Over the next few weeks, we will take a deeper dive into some of these inspection types. If you have any questions, or would like a quote on mechanical integrity services, call Keith Taylor, Director of Mechanical Integrity Services at 716.592.3980, ext. 143, or email him at [email protected].
