Overview
ISO 16145-4:2013 is an international standard developed by the International Organization for Standardization (ISO) addressing the automated measurement method for assessing total water-soluble salts on steel surfaces prior to the application of protective coatings. Part of the ISO 16145 series on ships and marine technology, this standard is intended for new building stages and supports compliance with the Performance Standard for Protective Coatings (PSPC) as stipulated by the International Maritime Organization (IMO) resolutions, including Res.MSC.215(82), Res.MSC.244(83), and Res.MSC.288(87).
The standard provides clear technical requirements and guidance for rapid, accurate, and automated measurement, using a conductivity meter, to ensure steel surfaces are adequately cleaned of ionic contaminants-such as chlorides and sulfates-before coating applications in critical marine environments.
Key Topics
-
Purpose and Scope
ISO 16145-4:2013 covers automated methods to measure the overall surface density of water-soluble salts on steel, critical for maintaining the integrity of protective coatings in ballast tanks, void spaces, and cargo oil tanks.
-
Measurement Principle
The method uses a specially designed detector and a conductivity meter. Salts are dissolved from a steel surface using water and the conductivity of the extract is measured, indicating the presence and quantity of ionic contaminants.
-
Instrumentation and Requirements
- Use of standardized solutions for calibration and verification
- Detectors with defined areas, electrodes, and temperature sensors
- Conductivity meters with specific measurement ranges, accuracy, and calibration intervals
- Use of high-purity water (at least ISO 3696 grade 3) for extraction and instrument cleaning
-
Procedures
- Blank tests for instrument baseline
- Consistent extraction techniques as per manufacturer instructions
- Cleaning protocols between measurements
- Direct-reading instruments or calculations based on conductivity differences
-
Result Expression
Results are displayed in units such as mS/m, μS/cm, mg/m², or μg/cm², enabling clear assessment of the total amount of water-soluble salts.
Applications
ISO 16145-4:2013 serves multiple practical roles within the marine industry:
- Shipyards and Shipbuilders: Ensures steel surfaces meet PSPC requirements, leading to extended coating life and reduced maintenance costs for seawater ballast tanks, bulk carrier void spaces, and oil tankers.
- Coating Manufacturers and Applicators: Enables verification of surface preparation, ensuring optimal coating performance and reduced risk of premature coating failures.
- Coating Inspectors: Provides a repeatable and standardized method for evaluating surface cleanliness, supporting compliance audits and quality assurance.
- Regulatory Compliance: Fulfills mandatory requirements under various IMO performance standards, contributing to vessel safety and environmental protection.
- Alternatives to Manual Methods: Offers rapid, automated measurement as an alternative to manual Bresle method and is recognized as equivalent to ISO 8502-9 under certain conditions.
Related Standards
Users of ISO 16145-4:2013 may also reference the following standards for related procedures and guidance:
- ISO 8502-9:1998: Field method for the conductometric determination of water-soluble salts
- ISO 3696: Water for analytical laboratory use - Specification and test methods
- NACE SP0508:2010: Methods of Validating Equivalence to ISO 8502-9 on Measurement of the Levels of Soluble Salts
- ISO 8502-6: Extraction of soluble contaminants for analysis - The Bresle method
- Other Parts of the ISO 16145 Series: Covering specific requirements for dedicated seawater ballast tanks (Part 1), void spaces (Part 2), cargo oil tanks (Part 3), and assessment of damaged coatings (Part 5, under development)
By integrating ISO 16145-4:2013, organizations can ensure that vessel coatings are applied to surfaces of verified cleanliness, ultimately improving corrosion resistance, coating longevity, and regulatory compliance in demanding marine environments.