ISO 7382:2023

Ethylene for industrial use - Sampling in the liquid and the gaseous phase

This document describes the procedures and the precautions to be taken in drawing representative samples of ethylene in the liquid phase stored at -100 °C and in the gaseous phase, for the purpose of their analysis. Annex A sets out a diagrammatic representation of a system for the disposal of the portion of the sample which is not used in the analysis.

Éthylène à usage industriel — Échantillonnage en phase liquide et en phase gazeuse

General Information

• Status: Published
• Publication Date: 02-Jul-2023
• ICS: 71.080.10 - Aliphatic hydrocarbons
• Technical Committee: ISO/TC 47 - Chemistry
• Drafting Committee: ISO/TC 47 - Chemistry
• Current Stage: 6060 - International Standard published
• Start Date: 03-Jul-2023
• Due Date: 09-Jul-2023
• Completion Date: 03-Jul-2023

Relations

• Revises: ISO 7382:1986 - Ethylene for industrial use - Sampling in the liquid and the gaseous phase
• Effective Date: 06-Jun-2022

Overview

ISO 7382:2023 - Ethylene for industrial use - Sampling in the liquid and the gaseous phase - specifies procedures and precautions for drawing representative samples of ethylene in both the liquid phase (stored at about −100 °C) and the gaseous phase for subsequent analysis. The standard covers sampling apparatus examples (non‑closed and several closed systems), purging and filling procedures, safety requirements, maintenance, reporting and a diagrammatic sample disposal system (Annex A). ISO 7382:2023 replaces the 1986 edition and expands scope to include sampling for trace polar compounds.

Key topics and requirements

• Scope and purpose
  • Sampling representative ethylene samples in liquid (cryogenic) and gas phases for analysis.
• Safety precautions
  • Follow ISO 3165:1976 and applicable legal/statutory regulations.
  • Ethylene properties noted: boiling point ≈ −103.9 °C, critical temperature 9.5 °C, critical pressure 5.04 MPa.
  • Requirements: adequate ventilation, electrical grounding, thermal protection for operators (insulating gloves, goggles), pressure‑rated equipment and periodic pressure testing.
• Apparatus types
  • Non‑closed sampling apparatus (open venting during purge/sample): typical components include sampling cylinder (tested at 34.5 MPa), dip pipe (fill to ~30% capacity), T‑union, passivated stainless‑steel connecting pipes and vent line.
  • Closed sampling apparatus (no release of sample/vapour): multiple closed systems described, including variants with heated regulators and fully passivated configurations.
  • Material & surface treatment: fluorocarbon‑lined or specially passivated sampling cylinders and stainless steel are recommended to avoid loss or reaction of trace polar compounds.
• Procedures
  • Stepwise purge, fill and vent instructions to obtain representative samples without contamination or excessive vapor release.
  • Avoid excessive purging to prevent icing and atmospheric pollution.
• Maintenance & reporting
  • Guidance on regular maintenance of sampling apparatus and standardized sampling reports to document conditions and traceability.
• Sample disposal
  • Annex A provides a diagrammatic system for safe disposal of unused liquefied or gaseous light olefin samples.

Applications

ISO 7382:2023 is intended for:

• Petrochemical and chemical plants producing, storing or distributing ethylene
• Laboratory analysts and QA/QC personnel performing composition and impurity analyses (including trace polar compounds)
• Sampling technicians, safety officers and regulatory compliance teams involved in cryogenic and pressurized gas sampling
• Engineering teams specifying sampling systems and procurement for cylinder and line materials

Keywords: ethylene sampling, liquid ethylene, gaseous ethylene, cryogenic sampling, closed sampling apparatus, non‑closed sampling, passivated sampling cylinder, sample disposal, ISO 7382:2023.

Related standards

• Normative reference: ISO 3165:1976 (Sampling of chemical products for industrial use - Safety in sampling)
• Applicable national regulations for pressure vessels, transportation of hazardous materials and environmental/safety legislation (as noted in ISO 7382:2023).

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 7382
Second edition
2023-07
Ethylene for industrial use —
Sampling in the liquid and the gaseous
phase
Éthylène à usage industriel — Échantillonnage en phase liquide et en
phase gazeuse
Reference number
© ISO 2023
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
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Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Safety precautions. 1
5 Sampling from a container filled with ethylene in the liquid phase .2
5.1 General . 2
5.2 Non-closed sampling apparatus and procedure . 2
5.2.1 Sampling apparatus . 2
5.2.2 Procedure . 4
5.3 Closed sampling apparatus no.1 and procedure . 4
5.3.1 Sampling apparatus . 4
5.3.2 Procedure . 5
5.4 Closed sampling apparatus no.2 and procedure . 6
5.4.1 Sampling apparatus . 6
5.4.2 Procedure . 6
5.5 Closed sampling apparatus no.3 and procedure . 7
5.5.1 Sampling apparatus . 7
5.5.2 Procedure . 8
6 Sampling of ethylene in the gaseous phase . 8
6.1 General . 8
6.2 Non-closed sampling apparatus and procedures . 8
6.3 Closed sampling apparatus and procedures . 9
7 Maintenance of the sampling apparatus . 9
8 Sampling report . 9
Annex A (informative) System for the disposal of samples of liquefied or gaseous light
olefins .11
iii
Foreword
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bodies (ISO member bodies). The work of preparing International Standards is normally carried out
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www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 47, Chemistry.
This second edition cancels and replaces the first edition (ISO 7382:1986), which has been technically
revised.
The main changes are as follows:
— the Scope has been expanded to apply to sampling for the determination of trace polar compounds
in ethylene products;
— Clauses 2 and 3 have been added;
— content from Clauses 4 and 7, including safety precaution and maintenance of sampling apparatus,
has been moved elsewhere in the document;
— in Clause 4, the critical pressure for ethylene has been corrected to 5,04 MPa;
— in Clause 5, explanations regarding apparatus have been added;
— in Clause 5, some specific parameters, including volume of sampling cylinder, size of connecting
pipe and time to purge sampling cylinder, have been deleted;
— in 5.2.1, specially passivated sampling apparatus has been recommended, especially when sampling
for the determination of trace polar compounds in ethylene products.
— Annex A, and Figures 1, 5 and A.1 have been revised.
— in 5.2.2: the procedure of purging and sampling for non-closed sampling apparatus has been revised;
iv
— sampling apparatus -no.2 in the first edition and its procedure have been deleted and a new sampling
apparatus was introduced as closed sampling apparatus no.2;
— in 5.3, 5.4, 5.5, two closed-sampling apparatuses for liquefied ethylene and a sampling apparatus
with heated pressure regulator have been added.
— in 6.2, the connecting pipes for non-closed sampling of gaseous ethylene has been revised;
— in 6.3, the closed-sampling apparatuses for gaseous ethylene has been added.
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.
v
INTERNATIONAL STANDARD ISO 7382:2023(E)
Ethylene for industrial use — Sampling in the liquid and
the gaseous phase
WARNING — The use of this document can involve hazardous material, operation and equipment.
This document does not purport to address all of the safety problems associated with its use.
It is the responsibility of the users of this document to take appropriate measures to ensure
the safety, health of personnel prior to application of the document and fulfil other applicable
requirement for this purpose.
1 Scope
This document describes the procedures and the precautions to be taken in drawing representative
samples of ethylene in the liquid phase stored at -100 °C and in the gaseous phase, for the purpose of
their analysis.
Annex A sets out a diagrammatic representation of a system for the disposal of the portion of the sample
which is not used in the analysis.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 3165:1976, Sampling of chemical products for industrial use — Safety in sampling
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
closed sampling apparatus
set of apparatus assembled by a sampling cylinder and connecting pipes to take samples under closed
conditions, by which the sampling process does not permit the release of any sample or vapour to the
surrounding environment
3.2
non-closed sampling apparatus
set of apparatus assembled by a sampling cylinder and connecting pipes to take samples in open air, by
which the sampling process permits the release of sample or vapour to the surrounding environment
4 Safety precautions
The safety precautions in all sampling and testing operations with liquefied and gaseous ethylene shall
be carefully followed in accordance with ISO 3165:1976. Relevant legal and statutory regulations to
ensure the safety, health and environmental protection in the procedure of the sampling methods can
apply.
The ethylene shall be stored and transported in the liquid phase at a temperature below - 100 °C.
The critical temperature of ethylene is 9,5 °C and its critical pressure is 5,04 MPa. As the boiling
temperature of ethylene at atmospheric pressure is -103,9 °C, it follows that ethylene sampled in the
liquid phase cannot be kept in the state at room temperature, without taking account of the pressure.
All sampling equipment shall be capable of resisting the sample pressure after complete vaporization. It
is presupposed that the use of the vessels, the plant and the equipment conform to the legal regulations
in force. Users shall have the vessels periodically pressure tested by an approved organization.
The construction materials shall be capable of withstanding rapid changes in temperature, for example,
rising from – 100 °C to +20 °C in 1 to 2 min. Passivated stainless steel should be selected for preference.
Owing to the low temperatures of the product and its associated equipment, operators shall wear well-
insulating, non-cracking plastics or rubber-coated gloves to protect themselves from burns. They shall
also wear close-fitting protective goggles.
Ethylene is extremely flammable, and all precautions shall be taken to avoid forming an explosive
atmosphere. Suitable ventilation is essential, particularly during the purging operations.
Also, the sampling apparatus shall always be electrically grounded.
The safety precautions shall be taken when cleaning apparatus, discharging ethylene, wastes liquid
and steam. The discharging site shall be equipped with safety devices. It is expected that the sites meet
relevant safety, health and environmental protection requirements.
If the container is to be transported, it is expected to conform to specifications of applicable legislation
regarding transportation for hazardous materials.
5 Sampling from a container filled with ethylene in the liquid phase
5.1 General
Given the wide variation in the sampling apparatus for ethylene, it is difficult to specify a uniform
method for obtaining representative samples of heterogeneous mixtures. The four examples of non-
closed and closed sampling apparatus described in 5.2 and 5.3 have been found satisfactory and are
available commercially. Any other sampling apparatus may be used, however, it is presupposed that
they
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