What's a Corrosion Coupon Rack & Do I Need One?

Source: Chemtex

Understanding Corrosion Coupons

A corrosion coupon rack is a simple yet effective tool for monitoring corrosion in water systems. It uses corrosion coupons—small metal strips that match the materials used in your system. These coupons are carefully weighed before installation and then placed in the rack, where water passes through them continuously for 90 to 100 days. At the end of the test period, the coupons are removed, reweighed in a lab, and analyzed. The difference in weight reveals how much corrosion occurred during that time.

Why Install a Corrosion Coupon Rack?

Monitoring corrosion is essential to maintaining the health and efficiency of your water system. Corrosion coupon testing offers valuable insights into the effectiveness of your current water treatment program. If corrosion inhibitors are properly maintained, the test results should align with or surpass industry standards, helping you verify that your system is being protected.

Benefits of Corrosion Coupon Racks:

• Affordable and Easy to Use: Coupon racks are a simple and low-cost investment that delivers measurable feedback on your water treatment strategy.

• Visual Monitoring Option: Using clear PVC piping, operators can observe the coupons mid-test without needing to remove them.

Limitations of Physical Coupons vs. Linear Polarization Resistance (LPR) Probes

• Delayed Results: Because the test requires 90–100 days, coupons do not offer immediate insights.

• Lack of Time-Specific Data: Coupons reveal overall corrosion but not when it occurred. Pairing with real-time monitoring tools—such as automated control systems—provides a more comprehensive picture.

• Linear Polarization Resistance (LPR) Monitoring Probes: Enables the measurement of corrosion rates in real-time. This technique is beneficial for rapidly identifying corrosion upsets and initiating remedial action, thereby prolonging the life of plant equipment.  This method is enhanced when paired with remote monitoring controls.

Installation Tips

To ensure reliable results, consider these factors:

• Proper Placement: Racks installed too close to heat sources may exaggerate corrosion, while those placed after cooling towers may lower the rates.

• Seasonal Timing: Avoid conducting tests during spring or fall, when inconsistent flow may skew data.

• Flow Dynamics: Ensure proper flow rate, direction, and spacing are in place since they impact the study’s results.

• Avoid Contamination: Even small contaminants, such as oils from your hands, can affect results. Handle coupons with care and maintain clean systems.

Once testing is complete, our team provides a detailed report categorizing the corrosion rate as excellent, good, moderate, or poor based on industry benchmarks. These insights can help determine whether your water treatment program needs adjustment.

Unchecked corrosion can lead to major repairs or the replacement of costly equipment. Using a coupon rack enables you to take a proactive and affordable approach to monitoring and managing system health.

Our experts can help you identify the best corrosion-monitoring solution for your facility. To get started, contact your Boland Water Treatment representative by completing the form below.