ISO 25175:2026

Overview

ISO 25175:2026, Marine technology - Standard test methods for performance of reverse osmosis (RO) and nanofiltration (NF) membrane elements, establishes internationally recognized testing protocols for assessing the quality and capabilities of RO and NF membrane elements used in marine applications. Developed by the International Organization for Standardization (ISO), this standard addresses the need for uniform assessment methods, facilitating objective comparison and selection of membrane elements across various manufacturers and applications. Ensuring consistent performance testing is essential for operators, manufacturers, and researchers working in water treatment and seawater desalination.

Key Topics

• Air Tightness Testing: Specifies procedures based on vacuum decay test methods for verifying the integrity of spiral wound and hollow fiber membrane elements prior to performance testing. Ensures that membranes are leak-free and suitable for further evaluation.
• Separation Performance Testing: Outlines methods for measuring membrane permeation (water flow rate) and salt rejection, critical for evaluating the efficiency of water purification and desalination systems.
• Standardized Test Conditions: Recommends solutions, operating pressures, temperatures, and recovery rates tailored to different membrane types (such as seawater RO, brackish water RO, low-pressure RO, and NF membranes).
• Reporting and Data Accuracy: Details the necessary elements of a comprehensive test report, including membrane specifications, test conditions, measurement results, and any deviations from standard procedures. Emphasizes accurate data recording and calculation methods for repeatable and reliable results.

Applications

ISO 25175:2026 plays a pivotal role in various applications within the marine technology and water treatment sectors:

• Seawater Desalination: Used by plant operators and engineers to evaluate and select membrane elements for optimal system efficiency and longevity.
• Industrial Water Treatment: Supports consistent performance comparisons when integrating RO and NF membranes for process water preparation, reuse, or recycling.
• Membrane Manufacturing and R&D: Provides a uniform testing reference for developers and manufacturers seeking objective benchmarks and for researchers comparing membrane technologies.
• Quality Assurance and Procurement: Enables purchasers and regulatory bodies to verify performance claims, streamline procurement processes, and ensure component compatibility and compliance with global best practices.
• Technical Communication: Facilitates clear technical communication between manufacturers, users, and standardization bodies by defining test procedures and expected reporting formats.

Related Standards

To ensure robust and holistic membrane evaluation, ISO 25175:2026 references and complements several key international standards and guidance documents:

• ISO 10523: Water quality - Determination of pH (used for feed solution preparation)
• ISO 13205:2024: Marine technology - Seawater desalination - Vocabulary
• ISO 20468-5: Guidelines for performance evaluation of treatment technologies for water reuse systems - Part 5: Membrane filtration
• ISO 23446:2021: Marine technology - Product water quality of seawater reverse osmosis (RO) desalination - Guidelines for municipal water supply
• ASTM D5907-18: Standard test method for filterable matter (total dissolved solids) and nonfilterable matter (total suspended solids) in water
• ASTM D3923, D4194, D5615, D6161, D6908: Covering leak detection, operating characteristics, and terminology for membrane processes.

ISO 25175:2026 offers practical value by setting a standardized, internationally agreed framework for testing RO and NF membrane elements, ultimately enhancing reliability, transparency, and efficiency in the marine technology and water treatment industries.