oSIST prEN ISO 9455-8:2026

• Abstract:

  This document specifies a method for the determination of the zinc content of water soluble fluxes of type 3, as defined in ISO 9454-1 [1]. The method is intended to apply to an aqueous solution of flux containing approximately 25 % of zinc, expressed as zinc chloride (ZnCI2). For solid fluxes and for solutions whose concentrations differ appreciably from those stated above, an appropriate adjustment needs to be made to the amount of sample taken for the test.

• Status: Not Published
• Public Enquiry End Date: 01-Dec-2026
• ICS: 25.160.50 - Brazing and soldering
• Technical Committee: VAR - Welding
• Current Stage: 4020 - Public enquire (PE) (Adopted Project)
• Start Date: 10-Sep-2026
• Due Date: 28-Jan-2027
• Ref Project: prEN ISO 9455-8 - Soft soldering fluxes - Test methods - Part 8: Determination of zinc content (ISO/FDIS 9455-8:2026)

• Revises: SIST EN 29455-8:1998 - Soft soldering fluxes - Test methods - Part 8: Determination of zinc content (ISO 9455-8:1991)
• Effective Date: 01-Oct-2026

Overview

oSIST prEN ISO 9455-8:2026:2026, developed by CEN in collaboration with ISO, details standardized test methods for determining zinc content in soft soldering fluxes. This international standard focuses on water-soluble fluxes, particularly those containing approximately 25% zinc as zinc chloride. The document is a part of the ISO 9455 series, which covers various test methods for soft soldering fluxes, ensuring reliable quality and performance in soldering and brazing applications.

By systematically outlining the principle, reagents and materials, apparatus required, procedure, calculation of results, precision data, and requirements for the test report, oSIST prEN ISO 9455-8:2026 ensures repeatability and comparability of zinc determinations across laboratories and industries.

Key Topics

• Scope and Applicability:

  • Targeted at water-soluble fluxes of type 3 (as defined in ISO 9454-1).
  • Primarily for aqueous flux solutions with approx. 25% zinc content; adjustments recommended for solid fluxes or those with different concentrations.

• Analytical Principle:

  • Precipitation and removal of iron as hydroxide from an alkaline solution.
  • Determination of zinc via titration with EDTA, enabling precise quantification.

• Required Materials and Procedures:

  • Use only high-purity (analytical grade) reagents and distilled or deionized water.
  • Stepwise procedure includes dissolution, precipitation, and EDTA titration.
  • Execution in triplicate supports result validity and precision.

• Data Calculation and Reporting:

  • Percentage of zinc, usually expressed as zinc chloride, is computed based on titration results and sample density.
  • Comprehensive test report with sample identification, method reference, results, and any deviations or observations.

• Precision and Repeatability:

  • Interlaboratory studies demonstrate repeatability and reproducibility, ensuring confidence in the standard’s application.

Applications

oSIST prEN ISO 9455-8:2026 serves a range of stakeholders in the soldering industry, including manufacturers, quality assurance professionals, and regulatory bodies:

• Production Quality Control:

  • Ensures correct zinc content in soft soldering fluxes, critical for product performance and compatibility.

• Product Development and Compliance:

  • Assists R&D teams in formulating fluxes that meet international requirements.
  • Facilitates compliance with global regulations targeting consistent solder joint quality and reliability.

• Laboratory Testing:

  • Equips labs with a standardized, validated method for zinc determination, minimizing discrepancies in test results.
  • Supports interlaboratory comparisons and international accreditation.

• Procurement and Supply Chain:

  • Enables material specifiers and purchasers to verify flux composition through recognized testing protocols.

Related Standards

• ISO 9454-1: Soft soldering fluxes - Classification, labelling and packaging; referenced for type definitions and additional requirements.
• ISO 9455 Series: Contains multiple parts, each addressing different test methods for soft soldering fluxes.
• CEN/TC 121 and ISO/TC 44 Standards: Cover broader aspects of welding, soldering, and brazing materials and procedures.

By following oSIST prEN ISO 9455-8:2026:2026, organizations uphold best practices in quality management, product consistency, and regulatory compliance for soft soldering fluxes containing zinc.

SLOVENSKI STANDARD
01-november-2026
Talila za mehko spajkanje - Preskusne metode - 8. del: Določanje cinka (ISO/FDIS
9455-8:2026)
Soft soldering fluxes - Test methods - Part 8: Determination of zinc content (ISO/FDIS
9455-8:2026)
Flussmittel zum Weichlöten - Prüfverfahren - Teil 8: Bestimmung des Zinkgehaltes
(ISO/FDIS 9455-8:2026)
Flux de brasage tendre - Méthodes d'essai - Partie 8: Dosage du zinc (ISO/FDIS 9455-
8:2026)
Ta slovenski standard je istoveten z: prEN ISO 9455-8
ICS:
25.160.50 Trdo in mehko lotanje Brazing and soldering
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

FINAL DRAFT
International
Standard
ISO/FDIS 9455-8
ISO/TC 44/SC 12
Soft soldering fluxes — Test
Secretariat: DIN
methods —
Voting begins on:
2026-09-10
Part 8:
Determination of zinc content
Voting terminates on:
2026-12-03
Flux de brasage tendre — Méthodes d'essai —
Partie 8: Dosage du zinc
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/CEN PARALLEL PROCESSING LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
Reference number
ISO/FDIS 9455-8:2026(en) © ISO 2026

FINAL DRAFT
ISO/FDIS 9455-8:2026(en)
International
Standard
ISO/FDIS 9455-8
ISO/TC 44/SC 12
Soft soldering fluxes — Test
Secretariat: DIN
methods —
Voting begins on:
Part 8:
Determination of zinc content
Voting terminates on:
Flux de brasage tendre — Méthodes d'essai —
Partie 8: Dosage du zinc
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
© ISO 2026
IN ADDITION TO THEIR EVALUATION AS
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/CEN PARALLEL PROCESSING
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
or ISO’s member body in the country of the requester.
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
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Published in Switzerland Reference number
ISO/FDIS 9455-8:2026(en) © ISO 2026

ii
ISO/FDIS 9455-8:2026(en)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Reagents . 1
6 Apparatus . 2
7 Procedure . 2
8 Calculation of results . 3
9 Precision . 3
10 Test report . 3
Bibliography . 4

iii
ISO/FDIS 9455-8:2026(en)
Foreword
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