Failure analysis · Plate heat exchanger
Internal Leakage Caused by Incorrect Service Data
Failure analysis showing how inaccurate freshwater information led to unsuitable material selection and chloride attack.
Project summary
Challenge
The original specification described freshwater service but did not disclose the chloride exposure that governed corrosion risk.
Engineering response
Operating records and fluid chemistry were compared with the selected stainless grade and observed internal leakage.
Outcome
The case demonstrates that accurate service composition is essential to material selection, warranty assessment and safe life.
- Incorrect service information
- Chloride exposure
- Internal leakage
- Material selection lesson
Original project record
CASE STUDY
Premature Internal Leakage Caused by Incorrect Service Information
1. Project Background
A shell-and-tube heat exchanger was supplied for a cooling application.
According to the initial customer specification, the service medium was described as:
Fresh water
Based on this information, stainless steel material (SS316L) was selected for the tube bundle to balance corrosion resistance and cost efficiency.
No chloride content data, salinity level, or detailed water analysis report was provided at the quotation stage.
2. Initial Material Selection
Based on the declared condition ( fresh water ), the following assumptions were made:
- Low chloride concentration
- Neutral pH
- Non-aggressive environment
- Moderate operating temperature
Under such conditions, SS316L is generally considered acceptable and widely used in HVAC and industrial cooling systems.
3. Failure Occurrence
Within a relatively short operational period, internal leakage was reported.
Inspection revealed:
- Tube sheet area corrosion
- Localized pitting around tube-to-tube sheet joints
- Brownish corrosion deposits
- Evidence of internal cross-contamination
- Significant mineral deposition inside the tubes
(See attached inspection photos.)
One image clearly shows leakage emerging through a tube opening, indicating internal tube failure.