Method of sampling insulating liquids

This document is applicable to the sampling procedure used for insulating liquids in delivery containers and in electrical equipment such as power and instrument transformers, reactors, bushings, oil-filled cables, oil-filled tank-type capacitors, switchgear and load tap changers (LTCs). This document applies to liquids the viscosity of which at the sampling temperature is less than 1 500 mm2/s (or cSt). It applies to mineral oils and non-mineral oils (such as synthetic esters, natural esters, vegetable oils or silicones).

Verfahren zur Probennahme von Isolierflüssigkeiten

Méthode d'échantillonnage des liquides isolants

L'IEC 60475:2022 s’applique à la procédure d'échantillonnage utilisée pour les liquides isolants dans les récipients de livraison et les matériels électriques tels que les transformateurs de puissance et de mesure, les réactances, les traversées, les câbles à huile fluide, les condensateurs de puissance en huile, les appareillages de connexion et les changeurs de prises en charge (LTC - load tap changer). Le présent document s'applique aux liquides dont la viscosité, à la température d’échantillonnage, est inférieure à 1 500 mm2/s (ou cSt). Il concerne les huiles minérales et non minérales (les esters synthétiques, les esters naturels ou les huiles végétales et les liquides silicones, par exemple).

Metoda vzorčenja izolacijskih tekočin

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SLOVENSKI STANDARD
SIST EN IEC 60475:2022
01-september-2022
Nadomešča:
SIST EN 60475:2012
Metoda vzorčenja izolacijskih tekočin
Method of sampling insulating liquids
Verfahren zur Probennahme von Isolierflüssigkeiten
Méthode d'échantillonnage des liquides isolants
Ta slovenski standard je istoveten z: EN IEC 60475:2022
ICS:
29.040.01 Izolacijski fluidi na splošno Insulating fluids in general
SIST EN IEC 60475:2022 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN IEC 60475:2022
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SIST EN IEC 60475:2022
EUROPEAN STANDARD EN IEC 60475
NORME EUROPÉENNE
EUROPÄISCHE NORM July 2022
ICS 29.040.10 Supersedes EN 60475:2011
English Version
Method of sampling insulating liquids
(IEC 60475:2022)

Méthode d'échantillonnage des liquides isolants Verfahren zur Probennahme von Isolierflüssigkeiten

(IEC 60475:2022) (IEC 60475:2022)

This European Standard was approved by CENELEC on 2022-06-29. CENELEC members are bound to comply with the CEN/CENELEC

Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC

Management Centre or to any CENELEC member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by translation

under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the

same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,

Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the

Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,

Turkey and the United Kingdom.
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2022 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.

Ref. No. EN IEC 60475:2022 E
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SIST EN IEC 60475:2022
EN IEC 60475:2022 (E)
European foreword

The text of document 10/1163/FDIS, future edition 3 of IEC 60475, prepared by IEC/TC 10 "Fluids for

electrotechnical applications" was submitted to the IEC-CENELEC parallel vote and approved by

CENELEC as EN IEC 60475:2022.
The following dates are fixed:

• latest date by which the document has to be implemented at national (dop) 2023-03-29

level by publication of an identical national standard or by endorsement

• latest date by which the national standards conflicting with the (dow) 2025-06-29

document have to be withdrawn

This document supersedes EN 60475:2011 and all of its amendments and corrigenda (if any).

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

patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.

Any feedback and questions on this document should be directed to the users’ national committee. A

complete listing of these bodies can be found on the CENELEC website.
Endorsement notice

The text of the International Standard IEC 60475:2022 was approved by CENELEC as a European

Standard without any modification.
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SIST EN IEC 60475:2022
EN IEC 60475:2022 (E)
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

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.

NOTE 1 Where an International Publication has been modified by common modifications, indicated by (mod), the

relevant EN/HD applies.

NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available

here: www.cenelec.eu.
Publication Year Title EN/HD Year
IEC 60567 2011 Oil-filled electrical equipment - Sampling of EN 60567 2011
gases and analysis of free and dissolved
gases - Guidance
IEC 60970 - Insulating liquids - Methods for counting EN 60970 -
and sizing particles
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SIST EN IEC 60475:2022
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SIST EN IEC 60475:2022
IEC 60475
Edition 3.0 2022-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Method of sampling insulating liquids
Méthode d’échantillonnage des liquides isolants
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.040.10 ISBN 978-2-8322-3484-6

Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
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SIST EN IEC 60475:2022
– 2 – IEC 60475:2022 © IEC 2022
CONTENTS

FOREWORD ........................................................................................................................... 3

INTRODUCTION ..................................................................................................................... 5

1 Scope .............................................................................................................................. 6

2 Normative references ...................................................................................................... 6

3 Terms and definitions ...................................................................................................... 6

4 General principles for the sampling of insulating liquids ................................................... 7

4.1 New insulating liquids in delivery containers ........................................................... 7

4.1.1 Place of sampling ............................................................................................ 7

4.1.2 Quantity of sample to be taken ........................................................................ 7

4.1.3 Sampling equipment ........................................................................................ 7

4.1.4 Sampling procedure ....................................................................................... 11

4.2 Sampling of oil from oil-filled equipment ................................................................ 13

4.2.1 General remarks ............................................................................................ 13

4.2.2 Sampling of oil by syringe .............................................................................. 19

4.2.3 Sampling of oil by ampoule ............................................................................ 20

4.2.4 Sampling of oil by flexible metal bottles ......................................................... 21

4.2.5 Sampling of oil by glass and rigid metal bottles .............................................. 22

4.2.6 Sampling of oil by plastic bottles .................................................................... 23

4.3 Storage and transportation of samples .................................................................. 23

4.4 Labelling of samples ............................................................................................. 23

Annex A (informative) Procedure for sampling at intermediate levels (making up of the

average sample) ................................................................................................................... 25

A.1 Use of the thief dipper ........................................................................................... 25

A.2 Use of the pipette ................................................................................................. 25

A.3 Use of the siphon .................................................................................................. 25

A.4 General remark ..................................................................................................... 25

Annex B (informative) Procedure for testing the integrity of the syringes .............................. 26

Annex C (informative) Procedure for sampling oil from bushings .......................................... 27

Bibliography .......................................................................................................................... 29

Figure 1 – Thief dipper ............................................................................................................ 8

Figure 2 – Cream dipper ......................................................................................................... 9

Figure 3 – Pipette ................................................................................................................. 10

Figure 4 – Siphon ................................................................................................................. 10

Figure 5 – Sampling of oil by syringe .................................................................................... 15

Figure 6 – Sampling of oil by ampoule .................................................................................. 16

Figure 7 – Sampling of oil by bottle ....................................................................................... 17

Table 1 – Types of samples of new insulating liquids ............................................................ 11

Table 2 – Sample containers for oil tests .............................................................................. 18

Table 3 – Information required on oil sample labels .............................................................. 24

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SIST EN IEC 60475:2022
IEC 60475:2022 © IEC 2022 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
METHOD OF SAMPLING INSULATING LIQUIDS
FOREWORD

1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising

all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international

co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and

in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports,

Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). Their

preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with

may participate in this preparatory work. International, governmental and non-governmental organizations liaising

with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for

Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.

2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international

consensus of opinion on the relevant subjects since each technical committee has representation from all

interested IEC National Committees.

3) IEC Publications have the form of recommendations for international use and are accepted by IEC National

Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC

Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any

misinterpretation by any end user.

4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications

transparently to the maximum extent possible in their national and regional publications. Any divergence between

any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter.

5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity

assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any

services carried out by independent certification bodies.

6) All users should ensure that they have the latest edition of this publication.

7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and

members of its technical committees and IEC National Committees for any personal injury, property damage or

other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and

expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC

Publications.

8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is

indispensable for the correct application of this publication.

9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent

rights. IEC shall not be held responsible for identifying any or all such patent rights.

IEC 60475 has been prepared by IEC technical committee 10: Fluids for electrotechnical

applications. It is an International Standard.

This third edition cancels and replaces the second edition published in 2011. This edition

constitutes a technical revision.

This edition includes the following significant technical changes with respect to the previous

edition:

a) addition of a new Annex C on sampling of oil from bushings, at the request of IEC

subcommittee 36A, in order to transfer to IEC 60475 the corresponding contents of

IEC TR 61464 relating to oil sampling from bushings;
b) deletion of NOTE 2 in 4.2.1.2.
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SIST EN IEC 60475:2022
– 4 – IEC 60475:2022 © IEC 2022
The text of this International Standard is based on the following documents:
Draft Report on voting
10/1163/FDIS 10/1173/RVD

Full information on the voting for its approval can be found in the report on voting indicated in

the above table.
The language used for the development of this International Standard is English.

This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in

accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available

at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are

described in greater detail at www.iec.ch/publications.

The committee has decided that the contents of this document will remain unchanged until the

stability date indicated on the IEC website under webstore.iec.ch in the data related to the

specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
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SIST EN IEC 60475:2022
IEC 60475:2022 © IEC 2022 – 5 –
INTRODUCTION
General caution, health, safety and environmental protection

WARNING – This document does not purport to address all the safety problems associated with

its use. It is the responsibility of the user of this document to establish appropriate health and

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

The insulating oils which are the subject of this document should be handled with due regard

to personal hygiene. Direct contact with the eyes can cause irritation. In the case of eye contact,

irrigation with copious quantities of clean running water should be carried out and medical

advice sought. Some of the tests specified in this document involve the use of processes that

could lead to a hazardous situation. Attention is drawn to the relevant standard for guidance.

This document is applicable to mineral oils and non-mineral oils, chemicals and used sample

containers.

Attention is drawn to the fact that some mineral oils in service can still be contaminated to some

degree by PCBs. If this is the case, safety countermeasures should be taken to avoid risks to

workers, the public and the environment during the life of the equipment, by strictly controlling

spills and emissions. The disposal or decontamination of these oils can be subject to regulatory

requirements with regard to their impact on the environment. Every precaution should be taken

to prevent release of mineral oil and non-mineral oil into the environment.
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METHOD OF SAMPLING INSULATING LIQUIDS
1 Scope

This document is applicable to the sampling procedure used for insulating liquids in delivery

containers and in electrical equipment such as power and instrument transformers, reactors,

bushings, oil-filled cables, oil-filled tank-type capacitors, switchgear and load tap changers

(LTCs).

This document applies to liquids the viscosity of which at the sampling temperature is less than

1 500 mm /s (or cSt). It applies to mineral oils and non-mineral oils (such as synthetic esters,

natural esters, vegetable oils or silicones).
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.

IEC 60567:2011, Oil-filled electrical equipment – Sampling of gases and analysis of free and

dissolved gases – Guidance
IEC 60970, Insulating liquids – Methods for counting and sizing particles
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:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
3.1
delivery container
container used to store, transport and deliver batches of oil
EXAMPLE Drum, rail tanker, road tanker, flexible plastic bag.
3.2
electrical equipment
equipment filled with insulating oil

EXAMPLE Power and instrument transformers, reactors, bushings, oil-filled cables, oil-filled tank-type capacitors,

switchgear and load tap changers (LTCs).
3.3
sampling equipment

equipment used for sampling oil from delivery containers (e.g. sampling probes, such as dippers

or siphons) and from electrical equipment (e.g. connecting tubing and drain valve adapters)

Note 1 to entry: Sampling equipment also includes sample containers, waste oil containers and other accessories.

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SIST EN IEC 60475:2022
IEC 60475:2022 © IEC 2022 – 7 –
3.4
sample container

container or other device used to store and transport samples of oil for analysis

EXAMPLE Syringe, bottle, ampoule.

Note 1 to entry: Sample containers include accessories such as valves, tubing or caps attached to the container.

4 General principles for the sampling of insulating liquids
4.1 New insulating liquids in delivery containers
4.1.1 Place of sampling

The sample shall be taken from the part of the delivery container where the insulating liquid is

likely to be most heavily contaminated. To evaluate the quality of a consignment, two types of

samples may be normally taken:

a) composite sample: mixture of samples taken at the same level in several containers;

b) individual sample: sample or mixture of samples taken at the same level in one container.

From a delivery, individual samples of 1 l may be taken from different containers for the electric

strength test. Further tests may be carried out on these samples and a complete examination

on the mixture of these (composite sample).

In certain cases, it can be useful to constitute an average sample within the container. An

average sample is a mixture of samples taken at different levels in one container.

1) tankers: samples should be taken from each tanker as described in 4.1.4.2 below;

2) drums: samples should be taken as described in 4.1.4.3 below.
In the case of a single drum, this shall be sampled.

In case there is more than one drum of a lot of oil, sampling procedures should be negotiated

between supplier and user. For example, samples can be taken from 10 % of drums or at least

two drums, whichever the largest.
4.1.2 Quantity of sample to be taken
This depends on the tests to be performed and the procedures used.
Typically, 2 l are taken.
4.1.3 Sampling equipment
4.1.3.1 General

Since the results of the tests included in IEC requirements for insulating liquids can greatly

depend on the impurities in the sample, it is essential to observe the following precautions:

– separate sampling equipment shall be reserved exclusively for each type of liquid. All seals

and tubing used should be compatible with the insulating liquid to be sampled;

– the equipment shall be clean and dry, following the cleaning procedures described in

4.2.1.6. Particular care should be taken to ensure the absence of any traces of solid

impurities, such as dust, fibres. The use of rags for cleaning is not permitted.
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4.1.3.2 Sampling probes

As examples, four types of sampling probes are described below. Other probes may also be

used, provided they do not introduce any contamination. Stainless steel and aluminium are

suitable.
a) Sampling from tankers

The thief dipper shown in Figure 1 is suitable for taking samples at the bottom of the

container. This is a dipper constructed of stainless steel or aluminium tubes and castings,

machine-finished all over. It shall be sufficiently heavy to sink in the liquid. It should always

be suspended by means of a metal wire or chain. String or other fibrous materials shall not

be used.

The cream dipper is used for taking top samples of insulating liquids. This probe shall be

constructed as shown in Figure 2 and shall be of stainless steel.
Dimensions in millimetres
Figure 1 – Thief dipper
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SIST EN IEC 60475:2022
IEC 60475:2022 © IEC 2022 – 9 –
Dimensions in millimetres
Figure 2 – Cream dipper
b) Sampling from drums

The pipette shown in Figure 3 enables samples to be taken at the bottom of drums. This

pipette has a capacity of about 500 ml.

Another probe to take samples at the bottom is shown in Figure 4; it is a siphon with a glass,

stainless steel or aluminium tube having an internal diameter of about 13 mm for taking off

the sample liquid, and a metal tube (internal diameter 5 mm) for applying pressure. Both

tubes are set in an oil-resistant bung whose dimensions correspond to the diameter of the

bung hole in the drum. Commercial versions of this equipment are available. When possible,

glass is preferable for probes illustrated in Figure 3 and Figure 4.
The cream dipper (Figure 2) may be used for taking top samples.
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SIST EN IEC 60475:2022
– 10 – IEC 60475:2022 © IEC 2022
Dimensions in millimetres
Figure 3 – Pipette
Dimensions in millimetres
Figure 4 – Siphon
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SIST EN IEC 60475:2022
IEC 60475:2022 © IEC 2022 – 11 –
4.1.3.3 Sample containers

For storing and transporting samples, depending on the oil test to be performed, sample

containers of appropriate volume shall be used. Different types of sample containers are

indicated in 4.2.1.5.

For the mixing of different samples, a special sample container made of glass with a capacity

of at least 6 l shall be used. These special sample containers shall be closed in a manner that

allows them to be sealed, by means of oil-resistant plastic or compatible rubber tubing or screw

caps equipped with a polytetrafluoroethylene (PTFE) lining. Natural rubber tubing and/or seals

are not permitted. PTFE and polypropylene (PP) seals are acceptable.

Each sample container shall have a label on which are marked all the indications necessary to

identify the contents, i.e. the markings of the drums or tanks, date of sampling and the name of

the recipient.
4.1.3.4 Cleaning of sampling equipment

Sampling equipment shall be cleaned following the procedures described in 4.2.1.6.

4.1.4 Sampling procedure
4.1.4.1 General remarks

According to general principles for sampling (see 4.1.1), samples of new insulating liquid shall

be taken from the bottom of the delivery container, where the contamination is likely to be the

greatest. But in certain cases, an average sample is also of interest.

NOTE 1 To obtain an average sample, samples are taken at intermediate levels in tanks or drums. Examples of

procedures are given in Annex A. A procedure is indicated in the NOTE in 4.1.4.2 a) for obtaining the equivalent of

an average sample.
In Table 1 different cases are considered:
Table 1 – Types of samples of new insulating liquids
Type of delivery Recommended Equipment to be used Procedure Recommended
sampling quantity
Composite Pipette (Figure 3) 4.1.4.2 3 × 2 l
Drums or
Siphon (Figure 4) 4.1.4.2 1 l or 2 l
Individual
Thief dipper (Figure 1) 4.1.4.1 b) 3 × 2 l
Tankers Individual
None (valve) 4.1.4.1 a)
Pipette
or Annex A
Drums Average
Siphon ( Figure 3 and
Figure 4) 3 × 2 l
Thief dipper (Figure 1)
Tankers Average or
None (valve) 4.1.4.1 a)

NOTE 2 Before sampling from tankers, sufficient oil is pumped from the end of the delivery pipe, as indicated in

4.1.4.2.

Every precaution shall be taken during sampling in order to avoid contamination of the insulating

liquids. Outdoor sampling of insulating liquids in rain, fog or high wind is only permitted if all

precautions have been taken to avoid contamination of the liquid. In this special case, the use

of a cover is necessary.
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Condensation shall be avoided by warming the sampling equipment so as to be above the

ambient air temperature. Before use, the equipment shall be rinsed with the liquid being

sampled. The operator shall be warned not to let their hands come into contact with the surfaces

of sampling equipment subsequently in contact with the oil. The insulating liquids shall be

protected against light irradiation during transportation and storage.

On arrival at the laboratory, the sampling container shall not be opened immediately. It is

necessary to wait until the temperature of the sample is the same as the room temperature.

4.1.4.2 Sampling from tankers

Insulating liquids may be sampled either through the tank outlet or by a thief dipper or by a

cream dipper.
a) Sampling through the tank outlet

By this procedure, it is possible to obtain a sample representative of the bottom of the tank

after the tank has been allowed to stand for at least 1 h after the vehicle has arrived.

NOTE It may be possible, by this procedure, to obtain the equivalent of an average sample, if the sampling is

done directly after the vehicle has arrived.
In this case, the sampling procedure shall be as follows:
– remove the outlet valve shield, if fitted;

– remove all visible dirt and dust from the valve by means of lint-free clean cloths or oil-

resistant synthetic sponges;

– the outlet system (pump, delivery pipe), if incorporated, shall be started or opened as

appropriate in order to get a sample;

– open the valve and allow to flow, slowly, at least 10 l of insulating liquid into a waste oil

container. In any case, discard at least an amount of oil equivalent to the volume of the

pipe;
– rinse sampling bottles with the insulating liquid;
– fill sampling bottles at constant flow to avoid turbulence.
b) Sampling with a thief dipper or a cream dipper

This sampling should be carried out after the tank has been allowed to stand for at least 1 h

after the vehicle has arrived.
1) Procedure with the thief dipper (Figure 1) (bottom samples)

For taking bottom samples (i.e. within 1 cm to 2 cm from the bottom of the tank) the

dipper is lowered until the projecting stem of the valve rod strikes the bottom of the tank.

The dipper then fills. Filling is complete when no more air bubbles escape. The dipper

is then withdrawn and its contents poured into the sample container (in the case of an

individual sample) or into the special glass sample container for collecting and mixing

the various samples taken (in the case of a composite sample). In this latter case, the

sample container(s) is (are) filled with the mixture so obtained. During pouring of the

liquid, avoid forming air bubbles by pouring too quickly.
2) Procedure with the cream dipper (Figure 2) (top samples)
With the valve c
...

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