Overview
EN ISO 11127-7:2022 specifies test methods for the determination of water‑soluble chlorides in non‑metallic blast‑cleaning abrasives used for the preparation of steel substrates before painting. Part of the ISO 11127 series, this third edition (approved November 2022) defines three accepted analytical routes: amperometric titration, spectrophotometry, and ion chromatography. The standard includes sampling reference to ISO 11127‑1 and procedural requirements for extraction and analysis to ensure reliable chloride quantification.
Key topics and requirements
- Scope and purpose
- Measures water‑soluble chloride content in non‑metallic abrasives to control contamination that can promote corrosion or affect coating performance.
- Sampling
- Use representative sampling in accordance with ISO 11127‑1.
- Sample preparation
- Typical procedure: duplicate determinations, (100 ± 0.1) g test portion extracted with (100 ± 0.5) ml water in a 250 ml flask, shaken and allowed to stand, then filtered if necessary.
- Analytical methods specified
- Amperometric titration (silver nitrate titration): established method and included equipment requirements.
- Spectrophotometry (mercuric thiocyanate/ferric ion reaction): suitable for low concentrations; spectrophotometric kits and portable spectrometers enable field testing. Detectable down to ~0.1 mg/L.
- Ion chromatography: separates chloride from other anions and allows simultaneous sulfate analysis; detection also possible down to ~0.1 mg/L. Requires higher‑grade water (ISO 3696 grade 1).
- Reagents and apparatus
- Use analytical grade reagents and specified water purity (ISO 3696). Common apparatus listed include micro‑burettes, spectrophotometer and cuvettes, ion chromatograph system (eluent, pump, anion column, conductivity detector), membrane filters (0.45 µm), balance and pipettes.
- Reporting
- Results reported from duplicate tests with method details, detection limits and sample handling noted.
Practical applications
- Quality control for abrasive manufacturers and suppliers to certify low soluble chloride content.
- Coating specifiers, corrosion engineers, and surface preparation contractors to verify abrasives meet project souring and longevity requirements.
- Testing laboratories that perform incoming material inspection or pre‑blast checks, including portable field testing using spectrophotometric kits.
- Useful in project assurance where chloride contamination could compromise paint adhesion, accelerate corrosion, or invalidate warranty conditions.
Related standards
- ISO 11127‑1 - Sampling of non‑metallic blast‑cleaning abrasives
- ISO 11126 series - Types of non‑metallic abrasives and requirements
- ISO 3696 - Water for analytical laboratory use
- ISO 10304‑1 - Liquid chromatography determination of dissolved anions
Keywords: EN ISO 11127-7:2022, water-soluble chlorides, non‑metallic blast‑cleaning abrasives, amperometric titration, spectrophotometry, ion chromatography, surface preparation, ISO 11127, ISO 11126.
