Thickness Testing on Firetubes Using Ultrasonic (UT)

Service Line

Conventional NDT

Situation

Looking for a second opinion, a facility asked PROtect to perform thickness testing on firetubes heaters for a series of asphalt cement tanks. These tanks had been previously inspected by a large testing and inspection company.

We found that one tank had issues with carbon forming on the firetube because of the type of oil being heated up in the tank. This carbon built up a thick layer that insulated the firetube and prevented good heat transfer to the oil. This caused the firetube to superheat to levels that baked the carbon out of the steel, resulting in the steel delaminating on its exterior.

We recognized what could be happening and worked with the site maintenance personnel to remove the carbon from the pipe. This resulted in layers of the pipe being removed as well. Once all loose material was removed and the areas were ground down to be free of defects, we found the material to be very thin – around .170” with the original thickness being .375”.

If the line had failed, oil would enter the firetube and leak out the burner into the dike area. And to bring one of these tanks up to temperature takes months. To have a failure would be extremely costly to the plant and would be a nightmare to resolve because of the hot oil.

Because of this, the firetube had to be replaced before putting the tank back into service.

We were informed that this tank was regularly inspected by another large testing and inspection company. The facility was surprised that upon our first inspection, we found this problem with the firetube in T-4.

The Result

PROtect found the issue when the other company did not because our team members are thorough and take pride in their work. We looked a little longer, dug a little deeper, and had previous experience and insight into what could be found when there is build-up on the line and lack of heat transfer.

After our inspection, our facility contact was impressed, resulting in them choosing PROtect for more projects and introductions to their industry peers.