National foreword

This Published Document is the UK implementation of ISO/TR 5756:2026.

The UK participation in its preparation was entrusted to Technical Committee PTI/2, Liquid Fuels.

A list of organizations represented on this committee can be obtained on request to its committee manager.

Contractual and legal considerations

This publication has been prepared in good faith, however no representation, warranty, assurance or undertaking (express or implied) is or will be made, and no responsibility or liability is or will be accepted by BSI in relation to the adequacy, accuracy, completeness or reasonableness of this publication. All and any such responsibility and liability is expressly disclaimed to the full extent permitted by the law.

This publication is provided as is, and is to be used at the recipient’s own risk.

The recipient is advised to consider seeking professional guidance with respect to its use of this publication.

This publication is not intended to constitute a contract. Users are responsible for its correct application.

This publication is not to be regarded as a British Standard.

Compliance with a Published Document cannot confer immunity from legal obligations.

This Published Document was published under the authority of the Standards Policy and Strategy Committee on 31 October 2026.

Foreword

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The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types of ISO document should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).

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This document was prepared by Technical Committee ISO/TC 28, Petroleum and related products, fuels and lubricants from natural or synthetic sources, Subcommittee SC 7, Liquid Biofuels.

Any feedback or questions on this document should be directed to the user’s national standards body. A complete listing of these bodies can be found at www.iso.org/members.html.

Introduction

This document provides information on a volumetric practice observed in different laboratories and gas stations for estimating hydrocarbon and ethanol content in blends of fuel ethanol and gasoline. The information in this document is intended to support the understanding of approaches used in practice.

1 Scope

This document presents information on a volumetric practice used to estimate ethanol and hydrocarbon content in blends of fuel ethanol and gasoline. This practice is based on phase separation induced by a sodium chloride (NaCl) solution, allowing approximate observation of hydrocarbon fraction and aqueous fraction.

The approaches described in this document are intended for informational purposes only.

2 Normative references

3 Terms and definitions

4 Principle observed in practice

5 Description of reported practice

6 Interpretation of results as reported in practice

7 Observations and limitations