National foreword

This British Standard is the UK implementation of ISO 8573‑5:2025. It supersedes BS ISO 8573‑5:2001, which is withdrawn.

The UK participation in its preparation was entrusted to Technical Committee MCE/8/-/3, Air quality.

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.

Compliance with a British Standard cannot confer immunity from legal obligations.

This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 July 2025.

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 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).

ISO draws attention to the possibility that the implementation of this document may involve the use of (a) patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s) which may be required to implement this document. However, implementers are cautioned that this may not represent the latest information, which may be obtained from the patent database available at www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.

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

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISO's adherence to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.

This document was prepared by Technical Committee Technical Committee ISO/TC 118, Compressors and pneumatic tools, machines and equipment, Subcommittee SC4, Compressed air treatment technology.

This second edition cancels and replaces the first edition (ISO 8573‑5:2001), which has been technically revised.

The main changes are as follows:

a thermal desorption technique has been introduced to prevent the use of environmentally hazardous solvents;
a re-useable standardized adsorption agent has been introduced.

A list of all parts of the ISO 8573 series can be found on the ISO website.

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

Oil vapour is a common contaminant in compressed air and this document details the correct sampling methodology and assists the user in selecting equipment and instrumentation and the determination of the oil vapour concentration in compressed air.

Oil vapour is the sum of all gaseous hydrocarbons or organic compounds starting from n-hexane, consisting of the subgroups:

VOC’s: Volatile Organic Compounds C₆ (n-hexane C₆H₁₄ ) to C₁₆ (n-hexadecane C₁₆H₃₄)
SVOC’s: Semi Volatile Organic Compounds C₁₆ (> n-hexadecane C₁₆H₃₄) to C₂₂ (n-docosane C₂₂ H₄₆)

In addition, it is intended to be used to assess compressed air purity such that the purity class can be stated in accordance with ISO 8573‑1 for a total oil content of class 0, 1, 2, 3, 4, and X, and can be used only by agreement between consenting parties when measurements to purity class 0 are to be performed.

As stated in ISO 8573‑1:2010, 5.4: "Measurements for liquid oil and aerosols of oil shall be made in accordance with ISO 8573‑2. It is considered that, for classes 3, 4 and X, the oil vapour content is not expected to significantly affect the total concentration; therefore, the measurement of vapour is optional. Where it is deemed necessary to measure the oil vapour, then ISO 8573‑5 shall be used."

1 Scope

This document specifies the test method for determining the content of oil vapour in compressed air using pressurized sampling and gas chromatography.

This document elaborates sampling, measurement, evaluation, uncertainty considerations and reporting in respect of the compressed air purity class for oil, in accordance with ISO 8573‑1.

For organic vapours and other gaseous contaminants, the same sampling procedure can be used, however the analysis method will be different depending on the target component. As guidance, ISO 8573‑6 and ISO 16000‑6 can be used.

2 Normative references

3 Terms and definitions

4 Units

5 Reference conditions

6 Test methods

6.1 Indicative methods

6.2 Quantitative analysis using gas chromatography

7 Materials for sampling

7.1 Sampling system

7.2 Sorbent tube

8 Materials and apparatus for gas chromatographic analysis

8.1 Gas chromatograph

8.2 Thermal desorption apparatus

8.3 Calibration standards

9 Sampling

9.1 General

9.2 Sampling volume

9.3 Procedure

10 Sample analysis

11 Calculation of test results

12 Test report

13 Quality control

Bibliography

BS ISO 8573-5:2025

Compressed air. Contaminant measurement - Oil vapour content

Current

Published:

31 Jul 2025