Understanding Bresle Patches: A Guide to Salt Contamination Testing

Before the application of protective coatings, the surface of industrial steel materials is typically cleaned using abrasive blasting. However, this cleaning process often leaves a risk of contamination by water-soluble salts, which are naturally present in the environment. In some cases, abrasive blasting can even cause soluble salts to penetrate the steel material.

Salt residue can be a serious problem, as it can compromise paint adhesion and induce corrosion. Therefore, it is crucial to ensure that the salt level on the steel surface does not exceed acceptable limits. To measure this salt level, you can use the Bresle Method using Bresle Patch and PosiTector SST Soluble Salt Tester.

What is Salt Contamination Testing?

Salt contamination testing is a crucial step in ensuring the quality and durability of steel surfaces. According to ISO standards, this test involves extracting water-soluble salts from a blasted steel substrate and determining their concentration. If the salt concentration is within acceptable levels, no further action is generally required. However, if it exceeds acceptable levels, cleaning methods such as water/steam/alkaline cleaning may be necessary, as outlined in ISO 12944-4.

The Bresle Method for Testing Soluble Salt Contamination

The Bresle method is a standardized procedure used to assess the level of soluble salt contamination on a steel surface before coating. By placing a Bresle patch containing a known volume of deionized water onto the surface, the water extracts any soluble salts present. 

The increased conductivity of the extracted solution, as measured by a conductometer like the PosiTector SST, directly correlates with the concentration of soluble salts. To prevent premature coating failures, it's essential to ensure that the salt level remains below the specified acceptable limits, which are typically defined within project specifications.

What is the Bresle Patch?

The Bresle Patch is a patch used to measure the level of soluble salts on a surface before coating. The Bresle Patch is applied to the surface, and deionized water is injected underneath. Any salts present on the surface will dissolve in this water. The collected liquid is then extracted and its conductivity is measured. A higher conductivity indicates a higher salt content on the surface.

3 Bresle Method Patch Options

DeFelsko offers three patch options which are ideal for testing in accordance with the Bresle method.

1. PosiPatch: A Reusable Bresle Test Patch

PosiPatch is a reusable Bresle test patch equipped with a magnetic ring. It is designed for measuring salt contamination in accordance with ISO 8502-6 and 8502-9, the Bresle Method.

PosiPatch is equipped with two types of magnetic rings. The standard magnetic ring is suitable for flat surfaces with a diameter greater than 1 meter (40 inches). The flexible magnetic ring is specifically designed for curved surfaces such as tanks, pipes, or surfaces with an inner or outer diameter greater than 10 centimeters (4 inches).

2. DeFelsko Adhesive Patch: Self-adhesive Polyurethane Bresle Test Patch

The DeFelsko adhesive Bresle patch is a polyurethane-based adhesive patch designed for the determination of salt contamination according to ISO 8502-6 and 8502-9.

The patch offers a low adhesive property, facilitating easy removal without leaving any residual adhesive. The DeFelsko adhesive patch has a fluid capacity of 2-3 ml and a surface area of 1250 mm². It is suitable for application on a wide range of materials and surface geometries.

3. Latex Adhesive Patch

Latex Adhesive Bresle Method Patch is a latex patch that conforms to ISO 8502-6. This patch features an easy-open tab, a low-adhesion adhesive with TearGuard technology.

Due to its low adhesion, the latex patch can be easily removed from the surface with little to no residue, compared to conventional patches available on the market.

The latex adhesive patch can accommodate a fluid volume of 2-15 ml within a 1250 mm² area. 

Comparison of Three Bresle Patch Types

Salt Contamination Testing with the PosiTector SST

DeFelsko PosiTector SST

The PosiTector SST Soluble Salt Tester offers a streamlined approach to measuring soluble salt contamination. By combining the conductivity probe with either the Bresle Method PosiPatch or DeFelsko Adhesive Patch, you can efficiently assess salt levels.

The following parameters are measured by the PosiTector SST:

• Conductivity (µS/cm)
• Sampling Temperature (C° or F°) normalized to 25°C
• Test duration

Using these measurements, the PosiTector SST automatically calculates the surface density of salts (mg/m² or µg/cm²) based on ISO 8502-9 standards. This eliminates manual calculations and ensures accurate results.

The PosiTector SST not only calculates the change in conductivity and surface salt density but also stores these values for future reporting using DeFelsko's PosiSoft Software Solutions. This eliminates the need for manual unit conversions and temperature adjustments. Additionally, the test time is automatically measured and recorded.

When "Bresle Mode" is deactivated, the PosiTector SST can be used as a standard conductivity meter, making it ideal for testing abrasive materials according to ISO 11127 and ASTM D4940 standards.

DeFelsko offers a wide variety of PosiTector SST Soluble Salt Tester Kit options:

DeFelsko Distributor in Singapore

LFC PTE LTD is the authorized distributor of DeFelsko products in Singapore. Our expert team can assist you in selecting the appropriate DeFelsko Bresle Patch Solutions for your salt contamination testing needs.

Stay updated on DeFelsko products and other leading industrial inspection tools by following LFC PTE LTD on social media. You can find us on Facebook, Instagram, YouTube, and LinkedIn.