ISO 17308:2015

Petroleum products and other liquids — Ethanol — Determination of electrical conductivity

ISO 17308:2015 specifies a test method for the determination of the electrical conductivity in ethanol fuel and mixtures (including E85) in the range of 0,5 μS·cm−1 to 4 μS·cm−1 at a temperature of 25 °C. The electrical conductivity is determined from the measured electrical conductance.

Produits pétroliers et autres liquides — Éthanol — Détermination de la conductivité électrique

General Information

• Status: Published
• Publication Date: 14-Jan-2015
• ICS: 75.160.20 - Liquid fuels
• ICS: 75.160.40 - Biofuels
• Technical Committee: ISO/TC 28/SC 7 - Liquid Biofuels
• Drafting Committee: ISO/TC 28/SC 7 - Liquid Biofuels
• Current Stage: 9092 - International Standard to be revised
• Completion Date: 08-Oct-2020

Relations

• Consolidated By: ISO 3104:2020 - Petroleum products — Transparent and opaque liquids — Determination of kinematic viscosity and calculation of dynamic viscosity
• Effective Date: 06-Jun-2022

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 17308
First edition
2015-01-15
Petroleum products and other
liquids — Ethanol — Determination of
electrical conductivity
Produits pétroliers et autres liquides — Éthanol — Détermination de
la conductivité électrique
Reference number
ISO 17308:2015(E)
ISO 2015
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ISO 17308:2015(E)
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© ISO 2015

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ii © ISO 2015 – All rights reserved
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ISO 17308:2015(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Reagents ........................................................................................................................................................................................................................ 1

5 Apparatus ..................................................................................................................................................................................................................... 2

6 Sampling ........................................................................................................................................................................................................................ 2

7 Apparatus calibration ..................................................................................................................................................................................... 2

7.1 Cleaning of the sample vessel..................................................................................................................................................... 2

7.2 Cleaning of the measuring cell .................................................................................................................................................. 3

7.3 Checking the cell constant ............................................................................................................................................................. 3

7.3.1 Principle .................................................................................................................................................................................. 3

7.3.2 Procedure ............................................................................................................................................................................... 3

8 Measurement procedure .............................................................................................................................................................................. 3

8.1 Using thermostatic bath or thermostatic vessel ........................................................................................................ 3

8.2 Using thermo compensation ....................................................................................................................................................... 4

9 Expression of results ........................................................................................................................................................................................ 4

10 Repeatability, r ....................................................................................................................................................................................................... 4

11 Reproducibility, R ................................................................................................................................................................................................ 4

Annex A (informative) Guidance on conductance and conductivity .................................................................................... 5

© ISO 2015 – All rights reserved iii
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ISO 17308:2015(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

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 documents 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).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any

patent rights identified during the development of the document will be in the Introduction and/or on

the ISO list of patent declarations received (see www.iso.org/patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation on the meaning of ISO specific terms and expressions related to conformity

assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers

to Trade (TBT), see the following URL: Foreword — Supplementary information.

The committee responsible for this document is ISO/TC 28, Petroleum products and lubricants,

Subcommittee SC 7, Liquid biofuels.
iv © ISO 2015 – All rights reserved
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ISO 17308:2015(E)
Introduction

Conductivity is related to the electrical current which is achieved by the ions displacement into solution

in an electrical field.

The importance of measuring conductivity is due to its role in corrosion processes which can harm

metallic components and therefore cause bad engine functioning at long term.

Ethanol can be contaminated with ion solutions in many ways, such as water contamination, chemical

treatment in industrial processes, addition of chemical additives, incorrect transportation and storage,

generally related to the cleanliness of tanks.

The ascertainment of the conductivity is usually carried out through the measurement of the electrical

conductance between two platinum electrodes, immersed in an electrolytic solution and connected

to a source of alternating electromotive force of a typical frequency. The resulting current is directly

proportional to the number of ions present in the solution, mobility and ionic valence, and temperature.

In the measuring of the conductance, it is essential to use an alternating current in order to eliminate

the undesirable effects of faradaic currents. In the case of an alternating resultant current, an inversion

of the polarization occurs every half cycle and, consequently, the inversion of the flow of the migration

of the ions, leading to a non-faradaic process, which comprises the formation of a double electrical layer

in the electrode-solution interface, called double electrical layer, with the potential decreasing linearly

in the first part and exponentially in the second part.

In an alternating fashion, the surfaces of the electrodes act as capacitors; the capacitive current increases

with the frequency and the size of the electrodes. The control of these variables is in order, so that the

alternating current flows preferentially in the form of non-faradaic processes. With an alternating current,

there is a reduction of the polarization effect and, as a consequence, an absence of faradaic currents.

In this sense, platinization, that is, covering the surface of the electrodes with a layer of platinum black,

increases its surface area significantly and, consequently, its capacitance which causes a reduction in the

faradaic current. Further, as a result of the increase in capacitance, there is a reduction in the capacitive

reactance, favouring the flow of current in the cell.

For both a metallic or electrolytic conductors, the Ohm Law (E = I·R) sets forth that the intensity of the

current (I) which passes through an electrical conductor is inversely proportional to the resistance

(R), where E represents the difference in potential and the inverse of the resistance is the conductance

(G = 1/R).Further information is provided in Annex A.
© ISO 2015 – All rights reserved v
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INTERNATIONAL STANDARD ISO 17308:2015(E)
Petroleum products and other liquids — Ethanol —
Determination of electrical conductivity

WARNING — The use of this International Standard can involve hazardous materials. This

International Standard does not purport to address all the safety problems associated with its

use. It is the responsibility of the user of this International Standard to establish appropriate

safety and health practices and determine the applicability of regulatory limitations prior to use.

1 Scope

This International Standard specifies a test method for the determination of the electrical conductivity

−1 −1

in ethanol fuel and mixtures (including E85) in the range of 0,5 μS·cm to 4 μS·cm at a temperature of

25 °C. The electrical conductivity is determined from the measured electrical conductance.

2 Normative references

The following documents, in whole or in part, are normatively referenced in this document and are

indispensable for its
...