Tank Inspections

Here at NVI, we have experienced and highly qualified API 653 Inspectors and NDE Technicians.

Our out-of-service and in-service tank reports are designed to be concise, yet comprehensive, and include evaluations following API Standard 653, NDE data, and engineered repair recommendations. Industry and application-specific visual inspectors are available for your project and can be mobilized throughout the United States.

MFL Floor Scanners

The Magnetic Flux Leakage (MFL) system, is a method of non-destructive testing used to detect corrosion and pitting most commonly on the floor sections of above ground tanks. A powerful magnet is used to magnetize the floor of the tank. In areas where corrosion, pitting, dents, or in some cases, cracks are present, the magnetic field “leaks” from the steel allowing us to identify the suspect areas accurately. We can then present a detailed report to the client showing the areas in need of repair or replacement.

Vacuum Box

Vacuum Box testing is one of the safest and reliable non-destructive test methods. This method can locate leaks in a test area that cannot be directly pressurized. The test is performed by spraying a detergent (soap) based solution on an area, placing the vacuum box over said area, and creating a vacuum in the area that the solution was sprayed. If a leak is present in the testing area, the detergent solution will start to bubble.

Robotic Crawlers

By using the latest technology with robotic crawlers, we are able to inspect areas that were previously inaccessible by other means. Using high power magnets, the crawlers can travel up the sides of a tank to gather thickness measurements. The crawlers can also travel around the circumference of the vessel to gather readings. The crawlers can also be used to scan an area of a vessel. We have two types of crawlers. We have an automatic crawler that is controlled by a remote device. We also have a manual crawler that is attached to an extendable pole that the technician can manually slide up the sides of the tanks.

API 653 Inspection

NVI maintains trained API 653 inspectors on staff for external inspections, which cover the condition of the foundation, coating condition, insulation condition, and conditions of tank appurtenances, leaks, distortion, and settlement. Internal inspections focus on ensuring that there is no severe corrosion or leaks in the tank floor.

Settlement Surveys

Settlement surveys are performed to ensure that a storage tank remains level during its operations. Elevation Measurements are taken around the tank to ensure that there isn’t any tilting or sinking present. The settlement surveys focus not only on the shell side of the tanks, but the floors of the tanks are inspected as well to ensure that there isn’t any settlement that could affect the integrity of the tank by causing leaks, cracks, or buckling of the tank floor. Each survey is performed to the satisfaction of API653.