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.

4. Photo-Based Technical Observations

Based on the visual evidence: