Test for and interpret soluble-salt (chloride/contaminant) levels on a prepared steel substrate before coating

Steps

1. Confirm the two-part method: ISO 8502-6 specifies the Bresle patch extraction procedure (defined water volume in contact with a known surface area for a specified dwell time) and ISO 8502-9 specifies evaluating the extract by conductivity with a temperature-compensated meter
2. Check ISO's current catalog (iso.org) for the latest edition/confirmation status of 8502-6 and 8502-9 before citing an edition year in a QC record, since both have older base editions (8502-6 dates to 2006, 8502-9 to 1998) that may have been reconfirmed or revised
3. Follow manufacturer instructions for the specific Bresle patch/cell kit used, since dwell time and extraction technique affect repeatability
4. Convert the conductivity reading to an equivalent NaCl concentration using the kit manufacturer's or standard's conversion reference, and record both the raw conductivity and converted value
5. Compare against the project's or coating manufacturer's maximum allowable soluble-salt level (commonly expressed in µg/cm²) — the ISO methods measure and report the value but do not themselves set an acceptance threshold