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This document specifies a method for the measurement of focal spot sizes within the range of 5 µm to 300 µm of X-ray systems up to and including 225 kV tube voltage. This determination is based on the evaluation of an image with a dedicated focal spot that has been radiographically recorded using an edge and evaluated with a digital method.
The imaging quality and the resolution of X-ray images depend highly on the characteristics of the effective focal spot, in particular its size and the two-dimensional intensity distribution as seen from the detector plane.
For the characterization of commercial X-ray tube types (i.e. for advertising or trade), the nominal values of Annex A are preferred.
NOTE            The same procedure can be used at higher kilovoltages by agreement but the accuracy of the measurement can be poorer.

IEC 62271-208:2025 gives practical guidance for the evaluation and documentation of the external steady state power-frequency electromagnetic fields which are generated by HV switchgear and controlgear assemblies and prefabricated substations. Basic requirements to measure or calculate the electric and magnetic fields are summarised for assemblies covered by IEC 62271-200 and IEC 62271-201, and for prefabricated substations covered by IEC 62271-202.
NOTE 1 The methods described in this document refer to three-phase equipment. However, the methodology can be used correspondingly for any single- or multi-phase equipment covered by this document.
This document applies to equipment rated for voltages above 1 kV up to and including 52 kV and power-frequencies from 15 Hz to 60 Hz. The electromagnetic fields which are generated by harmonics or transients are not considered in this document. However, the methods described are equally applicable to the harmonic fields of the power-frequency.
Detailed generic information on requirements and measurements of low-frequency electromagnetic fields is given in IEC 61786-1 and IEC 61786-2.
This document covers evaluation under factory or laboratory conditions before installation. The electric and the magnetic fields can be evaluated either by measurements or by calculations.
NOTE 2 Where practicable, the methods described in this document can also be used for installations on site.
It is not within the scope of this document to specify limit values of electromagnetic fields or methods for the assessment of human exposure.

IEC 63409-3:2025 specifies test procedures for confirming the basic operational characteristics of power conversion equipment (PCE) for use in photovoltaic (PV) power systems with or without energy storage. The basic operational characteristics are the capability of the PCE before any limitations due to internal settings are applied to the PCE to meet specific grid support functions or specific behaviours against abnormal changes.
This document covers the testing of the following items:
a) Steady state characteristics
Test procedures to confirm operable range of PCE at steady state condition are described. The operable ranges in apparent power, active power, reactive power, power factor, grid voltage and grid frequency are confirmed according to the test procedures.
b) Transient-response characteristics
Test procedures to confirm PCE’s response against a change of operational condition are described.
This document only considers the changes within normal (continuous) operable ranges. Therefore, the behaviours against abnormal changes and grid support functions are out of the scope and are covered in other parts of this series.

IEC 61300-3-50:2025 describes the procedure to measure the crosstalk of optical signals between the ports of a multiport M x N (M input ports and N output ports) fibre optic spatial switch. This second edition cancels and replaces the first edition published in 2013. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition:
a) revising structure of the document.

The present document specifies technical requirements, limits and test methods for Millimeter Wave Security Scanners (mmWave SSC, SSC equipment) operating indoor in the band 69,8 GHz to 80,5 GHz. The operating frequency range is split into two bands 97 from 69,8 GHz to 79,9 GHz and 99 from 76,5 GHz to 80,5 GHz as defined in Decision (EU) 2025/105 [i.8]. Details on mmWave SSC equipment and the related categorization is further specified in clause 4.2. NOTE: The relationship between the present document and essential requirements of article 3.2 of Directive 2014/53/EU [i.1] is given in annex A.

IEC 60966-4-4:2025, which is a Detail Specification, relates to multi-channel semi-rigid cable assemblies composed of type 50-5 semi-rigid coaxial cables with foamed polyethylene dielectric (see Annex A) and connectors such as type 7-16 (IEC 61169-4), type 4.1-9.5 (IEC 61169-11), type N (IEC 61169-16), type S7-16 (IEC 61169-53), type 4.3-10 (IEC 61169-54), type L32 (IEC 63138-4), type 2.2-5 (IEC 61169-66), type NEX10 (IEC 61169-71), type MQ4 (IEC 63138-2) or type MQ5 (IEC 63138-3). It gives subfamily detail requirements and severities.
This document applies to the semi-rigid cable assemblies for mobile communication, in particular for the cable assemblies used between main feeder and antennas or between main feeder and equipment system or between remote radio heads and antennas. The operating frequency is up to 6 000 MHz.

IEC 61757-1-4:2025 defines the terminology, structure, and measurement methods of distributed fibre optic sensors for absolute strain measurements based on spectral correlation analysis of Rayleigh backscattering signatures in single-mode fibres, where the fibre is the distributed strain measurement element in a measurement range from about 10 m to tens of km. This document also applies to hybrid sensor systems that combine the advantages of Brillouin and Rayleigh backscattering effects to obtain optimal measurement quality. This document also specifies the most important features and performance parameters of these distributed fibre optic strain sensors defines procedures for measuring these features and parameters. This part of IEC 61757 does not apply to point measurements or to dynamic strain measurements. Distributed strain measurements using Brillouin scattering in single-mode fibres are covered in IEC 61757-1-2. The most relevant applications of this strain measurement technique are listed in Annex A, while Annex B provides a short description of the underlying measurement principle.

IEC 60794-1-131:2026 describes the test procedures used to establish uniform requirements for microduct used to install optical fibre cables by blowing technique for the mechanical property - microduct inner clearance test. This document applies to microduct for use in optical fibre cable installation by blowing.
NOTE Throughout the document, the wording “optical cable” can also include optical fibre units, microduct fibre units, etc.
This first edition cancels and replaces Method E31 of the first edition of IEC 60794-1-21 published in 2015, Amendment 1:2020. This edition constitutes a technical revision. edition includes the significant technical changes with respect to IEC 60794‑1‑21:2015/AMD1:2020:
a) Specification of Method E31.

This document establishes the steps of the overall process of pipeline rehabilitation, comprising:
strategic and tactical activities:
investigation and condition assessment of the existing pipeline;
pipeline rehabilitation planning;
operational activities:
project specification;
applications of techniques;
documentation of the design and application process.
This document defines general terms of pipeline rehabilitation and establishes the classification of families of renovation and trenchless replacement techniques, with description of their respective features.
This document is applicable to underground drains and sewers and underground water and gas supply networks.
This document does not apply to:
new construction provided as network extensions;
calculation methods to determine, for each viable technique, the characteristics of lining or replacement pipe material needed to secure the desired performance of the rehabilitated pipeline;
techniques providing non-structural pipe liners;
techniques for repair.

This document describes the general principles of field-flow fractionation and specifies parameters, conditions and minimal reporting requirements, as part of an integrated measurement system, required to develop and validate methods for the application of asymmetrical flow and centrifugal field-flow fractionation in the analysis of nano-objects and their aggregates and agglomerates in aqueous media. General guidelines and procedures are provided to aid the user.

IEC TS 62257-200:2026 provides a method for describing the results to be achieved by the electrification system independently of the technical solutions that could be implemented.
The purpose of this part of IEC 62257 is to provide a method to assist designers of renewable energy systems, project contractors and project developers to design the electrification system for isolated sites while matching the identified needs. This part of IEC 62257 assesses the needs of the users and the different power system architectures which can be used for meeting these needs. In relation to the needs of the different participants to the project, functional requirements to be achieved by the production and distribution subsystems are listed.
This document provides technical standardization to different stakeholders (including but not limited to project developers, financing agencies, testing agencies, installers, etc.) involved in electrification projects for access to electricity for those not solely connected to the regional grid, through the setting up of off-grid renewable energy and hybrid systems (including micro-grids) with a voltage less than or equal to 1 000 V for AC (alternating current) or a voltage less than or equal to 1 500 V for DC (direct current). This document could be used for rural electrification, also for electrification of remote sites in developed countries, or any requirement for electricity access that cannot be met by attaching solely to the national utility grid. They promote the use of renewable energies, but at this time they do not deal with clean-energy mechanisms development (CO2 emissions, carbon credit, etc.).

IEC 61935-2:2021 specifies test methods for balanced and coaxial cords, which are used as equipment cords, patch cords, and CP cords, within cabling systems, in accordance with ISO/IEC 11801-1. The test methods and associated requirements are provided to demonstrate performance and reliability and to ensure compatibility of these balanced and coaxial cords during their operational lifetime. This document may also be used for providing test methodology for assessing the performance of other cords.
This fourth edition cancels and replaces the third edition published in 2010. This edition includes the following significant technical changes with respect to the previous edition:
- inclusion of cords up to category 8.1 and category 8.2, as defined in ISO/IEC 11801-1.

IEC TR 63614-3:2026 describes the gap analysis for metaverse systems and equipment, including examination of existing standards and services/applications within the metaverse domain. The analysis includes a comprehensive review of developments in various Standards Development Organizations (SDOs) and the relevant industry.

IEC TS 62607-4-11:2026, which is a Technical Specification, specifies the dispersion stability by using the zeta potential (ζ) method for nano-carbon materials for lithium ion capacitors. This document describes not only the dispersion stability of nano-carbon materials but also the effect of different surfactants as well as the evaluation method for testing long-term dispersion stability using the zeta potential (ζ). This document describes:
• Dispersion stability of nano-carbon materials using zeta potential (ζ) for electrochemical capacitors using carbon nanomaterials as electrodes
• Effect of different surfactants
• Evaluation of long-term dispersion stability using the zeta potential (ζ) method

IEC TR 63645:2026 provides a comprehensive range of environment related information sources to assist with understanding, assessing, and advancing the environmental performance of lighting products.

IEC 63372:2026 describes principles and methodologies, specifies requirements and provides guidance for quantification and communication of carbon footprint a product (CFP), emission reductions and avoided emissions from electric and electronic (EE) products and systems. This document is also applicable to product-related GHG projects. The GHG quantification such as CFP is based on life cycle assessment (LCA) methods. This document is a basic environment horizontal publication focusing on essential requirements and is primarily intended for use by committees in the preparation of publications within the area of environment in accordance with the principles laid down in IEC Guide 123. Wherever applicable, it is the responsibility of committees to make use of environment basic publications in the preparation of their environment group and product publications. Committees can apply this document directly to products when they do not develop a product publication in the area of environment. This first edition of IEC 63372 cancels and replaces IEC TR 62725:2013 and IEC TR 62726:2014, which have been technically revised. This edition includes the following significant technical changes with respect to the previous edition: a) updating and enhancing content related to carbon footprint of a product to align with new or updated reference standards; b) including product and system in quantification of GHG emission reductions; c) adding the content related to avoided emissions including use cases in Annex D.

IEC TR 63139:2026 provides explanations and background information on electrical safety requirements in TC 34 standards.

This document specifies the crypto suite for AES-128 for the ISO/IEC 18000 air interface standards for radio frequency identification (RFID) devices. This document specifies the security services of an AES-128 crypto suite. AES has a fixed block size of 128 bits and a key size of 128 bits, 192 bits or 256 bits. This document uses AES with a fixed key size of 128 bits and is referred to as AES-128. This document specifies procedures for the authentication of a Tag and or an Interrogator using AES-128 and provides the following features: Tag authentication; Tag authentication allowing authenticated and encrypted reading of part of the Tag’s memory; Interrogator authentication; Interrogator authentication allowing authenticated and encrypted writing of part of the Tag’s memory; Mutual authentication. In this document, a Tag and an Interrogator can support one, a subset, or all of the specified options, clearly stating what is supported.