Prior to removing a failed tube, mark and photo-document the tube (gas flow direction, fluid flow direction, row number, elevation,
boiler section, etc.). The visual condition of nearby tubes and the proximity of the damaged tubing to attachments, sootblowers,
etc. should also be documented.
Samples should be a minimum of 18” long and cuts should be made well away of any visible damage. Dry
cuts should be made with an electric or air powered reciprocating saw or grinder with a thin cut-off wheel to obtain high quality
cuts. Tube ends should be sealed with tape to prevent contamination or loss of deposits or scale. The tube samples should
be carefully packed to prevent damage during shipment.
The following information should be provided with the tube sample(s):
Boiler operating pressure, temperature, steaming rate, and unit MW
- Drawing of boiler showing the location of each tube sample
Specified tube material, dimensions, etc.
- Operating hours since commercial operation date or tube replacement
- Tube failure
history of the boiler
- Boiler maintenance records (i.e., replacements or modifications) for the boiler section of concern
water chemistry (typical chemistry and frequency, extent, and duration of excursions)
- Layup procedures (short-term, long-term)
Any additional pertinent information on the unit