FAQ's (Frequently Asked Questions)
Why is salt contamination measurement important?
The presence of soluble salts has been shown to have a significant negative effect on coating performance and leads to premature coating failure. Salts remaining beneath a protective coating create an osmotic force that draws water from the atmosphere through the paint layer. The pressure created by this water underneath the coating overcomes the adhesive bond between the coating and substrate, resulting in corrosion, osmotic blistering and eventual coating failure. It is therefore critical to ensure that a substrate is free from soluble salt contamination before painting.
What is measured with the PosiTector SST?
The PosiTector SST includes a certified and traceable conductivity probe specifically designed for ISO 8502-6,9. Included with each probe is a Long Form Certificate of Calibration. The following parameters are measured by the PosiTector SST:
-Sampling Temperature (C° or F°) normalized to 25°C
Using the measured conductivity value and the sample test volume (set within the gage menu), the surface density of the salts (mg/m2 or µg/cm2) is automatically calculated in accordance with ISO 8502-9, saving the gage operator time and eliminating the chance of a calculation error.
What are some typical applications?
The PosiTector SST is ideal for:
(a) Testing substrates for the presence of soluble salts in accordance with ISO 8502-6,9 (the Bresle Method)
(b) Testing blast media in accordance with ASTM 4940 and ISO 11127-6 (determination of water-soluble contaminates in abrasives by conductivity measurement)
(c) Testing the conductivity of water within the range of 0-500 µS/cm
How is the PosiTector SST conductivity probe different than the conventional conductivity meters included with most other test kits?
The PosiTector SST conductivity probe is specifically designed for ISO 8502-6,9 and has a number of features not found in conventional conductivity meters including . . .
-An onscreen user interface to walk users through the Bresle test method, simplifying the task
-Tracking and reporting of test duration (the total time of contact between the solvent and substrate) as required by ISO 8502-6
-Automatic calculation of surface density with adjustments for different patch volumes – works with ANY Bresle-type patch
-Free software for viewing and reporting data
-Long form certificate of calibration traceable to NIST included at no extra charge. A certificate also comes with the included conductivity standard (calibration solution).
-Automatic 25°C temperature normalization
-Sample temperature recording as required by ISO 8502-9
-Purpose-built, 1 ml test cell is optimized for the range, resolution and test volume of the Bresle Method
-Rugged, stainless steel electrodes – ideal for industrial environments
-Two year warranty
What information does the PosiTector SST save in its memory for each test?
The PosiTector SST saves all measured information for each test. All information is also reported in PosiSoft software.
-Date and time of test
-Test duration (the total time of contact between the solvent and substrate)
-Background sample temperature (°C or °F)
-Final sample temperature (°C or °F)
-Increase in conductivity between background and final sample (µS/cm)
-Calculated surface density of soluble salts (mg NaCl/m2, mg CL/m2, µg NaCl/cm2, or µg Cl/cm2)
Do your instruments require any formal training for use? Do you offer ‘demo’ models?
No. Our instruments are designed for simple operation, feature easy-to-use menus, both full and quick instruction manuals, and helpful videos. In lieu of demonstration models, we provide unlimited technical support via telephone and/or email, and a limited 30-day money back guarantee.
Does the PosiTector SST need to be calibrated prior to use?
The PosiTector SST arrives fully calibrated and ready to measure. A Long-Form Certificate of Calibration traceable to NIST or PTB is included, which documents actual readings taken by your instrument at our calibration laboratory on standards traceable to a national metrology institute. Beware of ‘Certificates’ or ‘Certificates of Conformance’ offered by competitors. These typically do not include actual instrument readings, and are often insufficient to meet common quality requirements.
A Verification of Accuracy can be performed by the user by measuring known reference standards such as the supplied conductivity standard.
Does the PosiTector SST measure the concentration of individual salt ions?
The PosiTector SST measures the overall conductivity of the test solution, and using calculations specified in ISO 8502-9, converts this value into a total surface density of salts.
Does the PosiTector SST display readings in PPM of salt?
The PosiTector SST is built specifically for the Bresle test method which does not address PPM calculations. While empirical conversion factors exist for converting PPM to surface density, these are not recognized by any test method.
Can the PosiTector SST probe be immersed in the fluid it is testing?
Yes. By immersing only the test cell, the PosiTector SST is ideal for testing the conductivity of water within the range of 0-500 µS/cm.
Can the PosiTector SST be used to measure the salt concentration in blast media?
Yes. The PosiTector SST can be used as a conventional conductivity meter making it ideal for testing abrasive materials in accordance with ISO 11127-6 and ASTM D4940-15.
How often should the PosiTector probe be recalibrated? PosiTector probes include a Certificate of Calibration with no expiry or end date. They have no shelf life, therefore the length of time in the field is not a good indicator for recalibration intervals. Many organizations with quality programs and recertification programs require annual recalibrations, and this is a good starting point for most users. Manufacturers recommend that customers establish calibration intervals based upon their own experience and work environment. Based on our product knowledge, data and customer feedback, a one year calibration interval from the date the instrument was placed in service is a good starting point.