ISO/DIS 19230

DRAFT INTERNATIONAL STANDARD ISO/DIS 19230 ISO/TC 158 Secretariat: NEN Voting begins on: Voting terminates on: 2020-01-15 2020-04-08 Gas analysis — Sampling guidelines Analyse des gaz — Lignes directrices pour le prélèvement des échantillons ICS: 71.040.40 THIS DOCUMENT IS A DRAFT CIRCULATED FOR COMMENT AND APPROVAL. IT IS THEREFORE SUBJECT TO CHANGE AND MAY NOT BE REFERRED TO AS AN INTERNATIONAL STANDARD UNTIL PUBLISHED AS SUCH. IN ADDITION TO THEIR EVALUATION AS BEING ACCEPTABLE FOR INDUSTRIAL, This document is circulated as received from the committee secretariat. TECHNOLOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT INTERNATIONAL STANDARDS MAY ON OCCASION HAVE TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL TO BECOME STANDARDS TO WHICH REFERENCE MAY BE MADE IN Reference number NATIONAL REGULATIONS. ISO/DIS 19230:2020(E) RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT, WITH THEIR COMMENTS, NOTIFICATION OF ANY RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE AND TO PROVIDE SUPPORTING DOCUMENTATION. ISO 2020 ---------------------- Page: 1 ---------------------- ISO/DIS 19230:2020(E) COPYRIGHT PROTECTED DOCUMENT © ISO 2020

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Foreword .......................................................................................................................................................................... v

Introduction.................................................................................................................................................................... vi

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

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

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

4 Sampling plan .......................................................................................................................................................... 5

5 Sampling classification ........................................................................................................................................ 6

5.1 Sampling classification of gases ....................................................................................................................... 6

5.2 Sampling classification of liquified gas .......................................................................................................... 7

6 Technical specifications ...................................................................................................................................... 8

6.1 Overview ................................................................................................................................................................... 8

6.2 General considerations for gas sampling ...................................................................................................... 8

6.2.1 Adsorption, reaction and permeation of sampling system .............................................................. 8

6.2.2 Leaks and atmospheric diffusion in the sampling system ................................................................ 8

6.2.3 Leak testing of the sampling system ......................................................................................................... 8

6.2.4 Purging of sampling system ......................................................................................................................... 9

6.2.5 Homogeneity of gas ...................................................................................................................................... 12

6.2.6 Inert-gas purging .......................................................................................................................................... 12

6.3 Possible condensation during compressed gas sampling .................................................................... 12

6.4 Main condensations for liquefied gas sampling ...................................................................................... 13

6.5 Samples that are not feasible in containers or cannot be used for analysis directly ................. 13

7 Safety guidance in sampling ........................................................................................................................... 13

7.1 Overview ................................................................................................................................................................ 13

7.2 General recommendation ................................................................................................................................ 13

7.3 Specific recommendation for sampling a certain substance .............................................................. 14

8 Sampling devices................................................................................................................................................. 14

8.1 General provision ............................................................................................................................................... 14

8.2 Sample container ................................................................................................................................................ 15

8.2.1 Sample container material ........................................................................................................................ 15

8.2.2 Structure of sample container ................................................................................................................. 16

8.2.3 Volume of sample container ..................................................................................................................... 19

8.3 Sample probe ....................................................................................................................................................... 19

8.4 Pressure reducer and flow controller ......................................................................................................... 19

8.5 Sample pump ........................................................................................................................................................ 20

8.6 Sample line ............................................................................................................................................................ 20

8.6.1 Material of sample line ............................................................................................................................... 20

8.6.2 Length and diameter of sample line ...................................................................................................... 20

8.7 Connecters and seals ......................................................................................................................................... 20

8.8 Cleaning and drying of the sampling device ............................................................................................. 21

8.9 Connection of sampling devices .................................................................................................................... 21

9 Sampling ................................................................................................................................................................ 21

9.1 Sampling method block diagram .................................................................................................................. 21

9.1.1 Overview .......................................................................................................................................................... 21

9.1.2 Block diagram of compressed gas sampling method ...................................................................... 21

9.1.3 Block diagram of liquefied gas sampling method............................................................................. 23

9.2 Quality assessment of the sampling system .............................................................................................. 24

9.3 Sampling from the gaseous phase and sampling after evaporation of liquefied gas ................. 24

9.4 Direct sampling ................................................................................................................................................... 24

9.4.1 General provisions ....................................................................................................................................... 24

9.4.2 Direct sampling of gas in pressure receptacles ................................................................................. 25

9.4.3 Direct sampling of gas in pipelines ........................................................................................................ 25

9.5 Indirect sampling ................................................................................................................................................ 25

9.5.1 Indirect sampling of gas in pressure receptacles ............................................................................. 25

9.5.2 Indirect sampling of gas in pipelines .................................................................................................... 26

9.5.3 Leakage test of sample container ........................................................................................................... 26

9.5.4 Storage of samples ....................................................................................................................................... 26

9.6 Sampling records ................................................................................................................................................ 27

Annex A (informative) Examples of estimation of the purging time and purging cycles for

sampling system ........................................................................................................................................... 28

Annex B (informative) Direct sampling for gas in pressure receptables .............................................. 30

Annex C (informative) Direct sampling of gas in pipelines ........................................................................ 33

Annex D (informative) Fill-empty sampling method .................................................................................... 35

Annex E (informative) Evacuated-container sampling ................................................................................ 37

Annex F (informative) Evacuated-system sampling ..................................................................................... 41

Bibliography ................................................................................................................................................................. 43

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Any feedback or questions on this document should be directed to the user’s national standards body. A

The determination of gas composition, impurity concentration and physical properties depends to a

large extent on sampling technique. The use of correct sampling techniques is an important safety and

quality critical step in gas analysis. The design, construction and selection of the sampling equipment to

avoid hazardous situations and sampling errors are important and directly influence the results

obtained. Any slight carelessness, in exactitude or mistake will seriously influence safety and the

Gaseous products are stored and transported in pressure receptacles in the form of compressed or

liquefied gas or through gas pipelines. The sampling methods used differ depending upon the package,

This document provides technical guidelines for the sampling of gases in pressure receptacles and

This document gives the basic definitions of terms and general provisions relating to sampling for

gas analysis, including sampling devices, sampling methods, sampling technical considerations, and

This document applies to both direct and indirect sampling of gas in pressure receptacles and

pipelines, including pure gases and gas mixtures. Compressed and liquefied gases are both

This document applies to the sampling of processed gases and does not involve gas treatment

The sampling procedures specified are not intended for the sampling of special products which are the

subject of other International Standards, such as liquefied petroleum gases (ISO 4257) and gaseous

Warning — The use of this document may involve a number of hazards. This document does

not specify all the safety issues associated with the use of the standard. Users of this

document are responsible for establishing measures to ensure safety whilst gas sampling. All

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 16664, Gas analysis — Handling of calibration gases and gas mixture — Guidelines

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

all materials which are present completely in gaseous form at a temperature of 20 ° C under the

gas which, when packaged under pressure for transport, is entirely gaseous at all temperatures

Note 1 to entry: This category includes all gases with a critical temperature less than or equal to − 50 °C.

gas which, when packaged under pressure for transport, is partially liquid at temperatures

gas which is known to be so toxic or corrosive to humans to pose a health hazard or which is presumed

to be toxic or corrosive to humans because it has a LC50 value for acute toxicity equal to or less than

Note 1 to entry: Other risks such as tissue corrosiveness are sometimes associated.

gas stored in cylinders, tube, pressure drums, tanks and other pressure receptacles, and no fresh gas

components that comprise the sampling system mainly include sample lines, pressure

gas transmission and control system constructed by gas storage container or sample point of gas in

a sample assumed to have the same composition as the material sampled when the latter is considered

sampling in situations where there is a direct connection between the gas to be sampled and the

sampling in situation where there is no direct connection between the gas to be sampled and the

the planned procedure of selection, withdrawal and preparation of a sample or samples from a lot to

yield the required knowledge of the characteristic(s) from the final sample so that a decision can be

indirect sampling from a specific part of the stream of material with a certain volume at a specific time

direct sampling taken continuously from a stream of material with a constant flow rate in a certain

the space in the container not occupied by the material, or the distance between the material surface

that part of the total estimation error of a characteristic due to known and acceptable deficiencies in the

NOTE 1 to entry: Except for special provisions, all pressures mentioned in this standard are gauge pressures.

conduit to transfer a sample of gas from the sample place to the analytical unit or sample container

device inserted into the gas pipelines so that a representative sample of the flowing gas can be taken.

The sample probe will have a conduit to convey the sample from the flowing gas to a point external to

ratio of the mass of gas to the mass of water at 15 °C that would fill completely a pressure receptacle

Note 1 to entry: Synonyms are filling factor and filling degree, often expressed in kg/l or similar.

purging method by sequentially filling and emptying the sampling system repeatedly with the gas to be

the process that takes a sample in liquid form directly from the liquid phase of the liquefied gas

the process that takes a sample in gaseous form by vaporizing the sample from the liquid phase of the

a device fitted to an analyser for the direct sampling of liquefied gas in liquid form, which can keep the

For a sampling plan, first determine the sampling type (clause 5), then consider techniques of sampling

(clause 6), to determine the appropriate sampling process (clause 9) and sampling devices (clause 8)

In this document, the sampling classification is based on whether the gas is connected to the analyser.

In addition, the sampling methods vary among different gas packaging, storage methods and sampling

Direct sampling, if possible, is strongly recommended. In the case of indirect sampling, the potential loss

of component during the time between sampling and analysis should be studied and incorporated in the

In general, for gas in pressure receptacles the internal composition is relatively uniform and constant.

For gases in pipelines the purpose and controls required dictate the type of sampling used. The design

• Pass continuous samples into the analyser to measure both limit and average composition

When sampling liquefied gases, a representative sample is obtained by sampling from the liquid phase,

however occasionally it may also be necessary to sample the vapour phase, e.g. the gas phase

composition is frequently required in the preparation of calibration gas mixtures.

Sampling from the liquid phase is further sub-divided into sampling in liquid form or sampling after

evaporation. The method of sampling used is normally determined by a review of the physical

properties of the liquefied gas such as vapour pressure etc. Generally low temperature liquefied gases

and high pressure liquefied gases require evaporation whereas low pressure liquefied gases may be

For the liquefied gas sampling classification see Figure 3 which details the sampling methods that

For gas sampling, attention should be paid to but not limited to the following considerations to collect

Such problems can be minimized by choosing sampling devices of suitable materials (see clause 8 for

However, some slight adsorption is difficult to overcome. In this case, the sampling system should be

heated or continuously purged for a long period of time, and quality assessment of the sampling system

should be carried out according to 9.2. The adsorption shall be considered in the uncertainty budget.

Leaks in the sampling system not only result in a loss of gas from the system but also allow air to diffuse

into the system (the partial pressure of the component determines the direction of the diffusion)

The sampling system should be leak tested (see 6.2.3) prior to use to ensure the sample will not be

contaminated, the composition changed, or hazardous conditions created by the ingress of air.

Furthermore, the back-diffusion of air into gas venting lines should be avoided by, for example, using

All connections and welds shall be tested prior to first use. During subsequent re-use of the sampling

system re-connected parts should be retested for leaks. Other parts of the system should be regularly

retested, this is particularly important for corrosive gases. When sampling toxic gases leak testing shall

be performed before each use of the sampling system. The integrity of the sampling containers and their

a) Pressurization of the system, followed by monitoring of the static pressure with respect to time.

b) Evacuation of the system and monitoring the vacuum achieved. A deterioration in the vacuum

c) Pressurize the system and check all connections with a leak detection solution. Following the

use of leak detection solution, the system should be purged out to ensure dryness prior to use.

d) Use of a leak detector (e.g. mass spectrometry, where the system is filled with helium and the

The correct selection of a leak detection method depends upon the system requirements. For example,