TesTex NDT Services Page: Boiler Tube Inspections

TesTex State of the Art Products and Services For Non-Destructive Testing

TesTex provides very specialized inspections for Water Tube and Fire Tube boilers of all sizes. For Generating Banks in Drum-to-Drum Boilers, we provide full-length tube inspections that can detect and quantify flaws in the straight and bend sections of the Boiler Tubing. We can conduct this test from the Mud Drum (w/ CL to CL <25’) or Steam Drum. For the inspection of Boiler Generating Banks, we use the TesTex Eagle Plus Single and Multichannel Remote Field Electromagnetic Technique (RFET) System.

For the Furnace or Waterwall tubes in larger Industrial & Utility Boilers, we provide Boiler Waterwall Scanning services. This service detects ID or OD flaws on the hot-side half of the tube. To gain access to these areas, we can work from hard scaffolding or swing staging. In gas burning boilers, no surface preparation is needed for this service. The same is true for most oil burning units. If a boiler burns coal, many times a quality high-pressure water blast is all that is necessary. For the inspection of the waterwalls, we use the TesTex TS-2000 Tube Scanning system based on Low Frequency Electromagnetic Technique (LFET). Our TesTex LFET technology scans approx. 120 degrees of the tube circumference with a single pass of the LFET scanner. Any flaw indications (or areas that we cannot scan due to tube bends, welds, viewports, etc.) are proved-up using A-Scan Ultrasonics.

TesTex also provides O.D. scanning services for the Super Heater and Reheater areas of boilers, and sometimes even the Economizers. This service also employs the TesTex TS-2000 Tube Scanning System.

For the inspection of Generating Banks found in Drum-to-Drum Boilers, there are three other methods, which are Spot Check UT, IRIS Ultrasonic Testing, and I.D. Laser Profiling (LOTUS). Traditional Spot Check UT is conducting from the O.D. (fireside) of the tubes, and is generally limited to areas that a person can access, or “put his hands on.” This gives very limited coverage and leaves a large percentage of surface area untested. The IRIS Ultrasonic Testing method is conducted from the tube I.D., and is generally conducted from the boiler Steam Drum (IRIS can be conducted from the Mud Drum, but it is very difficult due to the usage of water as the couplant for UT). The IRIS UT Testing method is good for detecting and quantifying flaws in the straight/vertical sections of the Generating Bank, however, it does not take any data in the tube bends. While the IRIS UT Testing method is good, it requires that the tubes be very clean on the I.D. and does not have a very high through-put as far as the amount of tubes tested in a given shift (100-200 tubes tested in a single 10-12 hour shift). The LOTUS method of I.D. Laser profiling is a very effective method for any detecting & quantifying flaws on the inner diameter of a given boiler tube, however, the tubes have to be cleaned so that the laser is actually reading the base metal (ie/ there can be no scale or deposits), and only I.D. flaws are found; the LOTUS method is not applicable for any type of O.D. flaws.

TesTex offers IRIS Ultrasonic Testing for Boiler Generating Banks as a back-up method or the primary method of inspection. TesTex also offers Video Borescoping Services. We can also offer Spot Check UT for Boiler Generating Banks, however, we do recommend it if other methods, such as RFET, are applicable.

Besides the TesTex LFET, there are at least (4) other methods used for the inspection of Boiler Waterwalls. These methods are Spot Check UT, A-Scan UT, EMAT, and Scanning Thermograpy. Spot Check UT only gives thickness readings and gets very minimal coverage of the total surface area of the furnace waterwalls; the chances of finding I.D. flaw mechanisims using Spot Check UT are minimal at best. If Boiler Waterwalls have been sandblasted, A-Scan UT may be used to inspected larger areas of the furnace walls; in these cases, a steady flow of water is most often used as the couplant. The EMAT technique requires that any Boiler Waterwall surfaces be sandblasted. The EMAT technique does not inherently get good surface area coverage unless the inspection team does multiple passes using the EMAT probe. Scanning Thermography is the most recent development for the inspection of Boiler Waterwalls; however, it is not yet commercially available in enough capacity to address the needs of the U.S. Power Industry.

When boiler generating bank tubing is susceptible to corrosion within a few inches of the Mud Drum or Steam Drum, TesTex offers a Near Drum Inspection, which is a high-resolution test of the 4-6” of boiler tubing just outside the Mud or Steam Drum. This is done using the TesTex Octavision Near Drum Inspection Tool.

We also inspect Tubular Air Heaters when present on certain boilers.

TesTex also provides Full Boiler Life Assessment Inspections which include not only many of the NDT methods listed above, but inspections of piping, pressure parts, D/A Tanks, as well as other parts of the boiler proper.