Operating conditions for industrial-process measurement and control equipment -- Part 4: Corrosive and erosive influences

Considers the corrosive and erosive industrial environment to which land-based and offshore industrial-process measurement and control systems or parts of systems may be exposed during operation, during periods when they are installed but inactive, during storage or transportation. Maintenance and repair conditions are not considered.

Einsatzbedingungen für Meß-, Steuer- und Regeleinrichtungen in der industriellen Prozeßtechnick -- Teil 4: Korrosive und erosive Einflüsse

Conditions de fonctionnement pour les matériels de mesure et commande dans les processus industriels -- Partie 4: Influences de la corrosion et de l'érosion

Prend en considération les conditions d'environnement propres à la corrosion et à l'érosion auxquelles les systèmes de mesure et de commande des processus industriels ou les constituants de ces systèmes, situés à terre ou sur des plates-fomres en mer, peuvent être exposés en cours de fonctionnement, au cours de périodes pendant lesqueles ils sont installés mais ne sont pas actifs, en cours de stockage ou en cours de transport. Les conditions d'entretien et de réparation ne sont pas traitées.

Operating conditions for industrial-process measurement and control equipment - Part 4: Corrosive and erosive influences (IEC 60654-4:1987)

General Information

Status
Published
Publication Date
31-Oct-1998
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
01-Nov-1998
Due Date
01-Nov-1998
Completion Date
01-Nov-1998

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SLOVENSKI STANDARD
SIST EN 60654-4:1998
01-november-1998
Operating conditions for industrial-process measurement and control equipment -
Part 4: Corrosive and erosive influences (IEC 60654-4:1987)

Operating conditions for industrial-process measurement and control equipment -- Part

4: Corrosive and erosive influences
Einsatzbedingungen für Meß-, Steuer- und Regeleinrichtungen in der industriellen
Prozeßtechnick -- Teil 4: Korrosive und erosive Einflüsse
Conditions de fonctionnement pour les matériels de mesure et commande dans les
processus industriels -- Partie 4: Influences de la corrosion et de l'érosion
Ta slovenski standard je istoveten z: EN 60654-4:1997
ICS:
25.040.40 Merjenje in krmiljenje Industrial process
industrijskih postopkov measurement and control
SIST EN 60654-4:1998 en

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

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SIST EN 60654-4:1998
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SIST EN 60654-4:1998
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SIST EN 60654-4:1998
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SIST EN 60654-4:1998
NORME
CEI
INTERNATIONALE
IEC
654-4
INTERNATIONAL
Première édition
STANDARD
First edition
1987
Conditions de fonctionnement pour les matériels
de mesure et commande dans les processus
industriels
Quatrième partie:
Influences de la corrosion et de l'érosion
Operating conditions for industrial-process
measurement and control equipment
Part 4:
Corrosive and erosive influences
© CEI 1987 Droits de reproduction réservés — Copyright - all rights reserved

Aucune partie de cette publication ne peut être reproduite ni No part of this publication may be reproduced or utilized

utilisée sous quelque forme que ce soit et par aucun procédé, in any form or by any means, electronic or mechanical,

électronique ou mécanique, y compris la photocopie et les including photocopying and microfilm, without permission

microfilms, sans l'accord écrit de l'éditeur. in writing from the publisher

Bureau central de la Commission Electrotechnique Internationale 3, rue de Varembé Genève Suisse

CODE PRIX
Commission Electrotechnique Internationale
PRICE CODE
International Electrotechnical Commission
IEC MeaayHapo,aHas+ 3nenrporexHH4ecnaa
HoMHCCHH
• Pour prix, voir catalogue en vigueur
For price, see current catalogue
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SIST EN 60654-4:1998
654-4 © I E C 1987 3
CONTENTS
Page
FOREWORD 5
PREFACE 5
Clause
1. Scope 7
2. Object 7
3. General 9
4. Non-solid substances 9
4.1 Definitions
11
5. Gases and vapours
5.1 Contamination effects
5.2 Inorganic chlorine compounds
5.3 Explanation of contaminant severity levels
6. Aerosols
7. Liquids . . .
8. Solid substances
17
8.1 Kind of industrial-process and location within that process
8.2 Nature of solid substances in the environment which could affect
the instruments
In combination with 8.3
19
8.4 Frequency of occurrence
8.5 Size
19
8.6 Concentration in mg/kg or g/kg of dry air
8.7 Velocity in m/s
21
8.8 Thermal conductivity
21
8.9 Electrical conductivity
8.10 Magnetic permeability 21
21
8.11 Example given to demonstrate the use of the questionnaire
9. Flora and fauna 23
APPENDIX A — Industrial contaminants 25
27
APPENDIX B — Methods of classification of reactive environments
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SIST EN 60654-4:1998
654-4 0 I E C 1987 — 5—
INTERNATIONAL ELECTROTECHNICAL COMMISSION
OPERATING CONDITIONS FOR INDUSTRIAL-PROCESS
MEASUREMENT AND CONTROL EQUIPMENT
Part 4: Corrosive and erosive influences
FOREWORD

1) The formal decisions or agreements of the IEC on technical matters, prepared by Technical Committees on which all

the National Committees having a special interest therein are represented, express, as nearly as possible, an international

consensus of opinion on the subjects dealt with.

2) They have the form of recommendations for international use and they are accepted by the National Committees in that

sense.

In order to promote international unification, the IEC expresses the wish that all National Committees should adopt

the text of the IEC recommendation for their national rules in so far as national conditions will permit. Any divergence

between the IEC recommendation and the corresponding national rules should, as far as possible, be clearly indicated

in the latter.
PREFACE

This standard has been prepared by IEC Technical Committee No. 65: Industrial-process

measurement and control.
The text of this standard is based upon the following documents:
Six Months' Rule Report on Voting
65(CO)38 65(CO)41

Full information on the voting for the approval of this standard can be found in the Voting

Report indicated in the above table.
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SIST EN 60654-4:1998
7 —
654-4 I E C 1987 ©
CONDITIONS FOR INDUSTRIAL-PROCESS
OPERATING
MEASUREMENT AND CONTROL EQUIPMENT
Part 4: Corrosive and erosive influences
1. Scope

Part 4 of the standard considers the corrosive and erosive industrial environment to which

land-based and off-shore, industrial-process measurement and control systems or parts of

systems may be exposed during operation, during periods when they are installed but inactive,

during storage or transportation. Maintenance and repair conditions are excluded from this

part.

The environmental in fluences considered in this part are limited to those which may directly

affect performance of process-measurement and control systems or parts of such systems.

Effects of the specific environmental conditions on personnel are not within the scope of this

part. The appropriate values of the physical or chemical parameters listed here as well as the

qualitative descriptions of the environment should be used to define local environments in

which equipment is expected to operate, be transported and stored. Only conditions as such

are considered; the resulting effects of these conditions on instrument performance are

specifically excluded.

Many environmental conditions listed in this part are difficult to classify so that a qualitative

description is used to characterize the environment.
Object

The object of Part 4 of the standard is to provide users and suppliers of industrial-process

measurement and control systems and parts of such systems with a uniform listing and

classification of corrosive and erosive environmental conditions to which equipment may be

exposed in specified locations during operation, storage, handling and transportation. Condi-

tions for transportation are for equipment in suitable packages to prevent damage.

The listed environmental conditions are intended to serve as a basis for comprehensive

specifications.

One of the objects of this part is to minimize problems which might result from neglecting

considerations of specific operating conditions affecting performance of systems and parts of

systems.

An additional object of this part is to aid in the choice of specific limit values for use in the

development of evaluation specifications for industrial-process measurement and control

equipment.
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SIST EN 60654-4:1998
654-4 © I E C 1987 9
3. General

Industrial-process measurement and control equipment is used all over the earth, thus being

exposed to the characteristic environmental conditions of fauna and flora of tropical, tempe-

rate and arctic climates, as well as deserts, jungles, mountains and the sea.

Superimposed on these basic environmental influences and in addition to the general level

of ambient pollution prevalent in industrialized areas where process control equipment and

systems are heavily utilized, it should be recognized that higher levels of contamination do

generally exist in the localized areas where the process control equipment is deployed, as

contaminants are introduced into the environment by the very process that is being controlled.

These higher levels of contamination can occur permanently or temporarily. In many cases

the effects on measurement and control equipment are proportional to the concentration,

temperature and the period of exposure, these effects being often increased by humidity. It

is however very difficult to describe an environment by specifying the concentration of the

contaminant against time. Therefore, the concept of the average value was used as a basis for

quantitatively classifying the chemically active substances. But it is recognized that special

damage may be caused by short-time high concentration (peak value) of corrosive contami-

nants, therefore the peak values as defined below have been incorporated in the classification.

In Appendix A is given a listing of industrial contaminants associated with various process

plants. It is a guide to highlight the specific contaminants introduced by industrial processes.

Atmospheric contamination to which systems and parts of systems may be exposed include

gases, vapours, liquids and solids. The effects of these contaminants can be various, such as

the corrosive effects from chemically active contaminants, erosive effects from sand blasting

and clogging by dusts.

The different kinds of contaminants can also be present in combinations whereby more

severe environmental conditions can arise such as high humidity combined with chlorine gas;

therefore, the ambient temperature and relative humidity should be specified.

It is practically impossible to classify all the different environments, due to the unlimited

number of possible combinations and associated large number of effects and severities.

It is recognized that the effects of gases, vapours and liquids are primarily corrosive while

solid contaminants may cause adverse erosive, corrosive, thermal or electromagnetic effects.

Therefore, Clauses 4, 5, 6 and 7 classify the corrosive effects of non-solid chemically active

substances. Clauses 8 and 9 are enumerations of other environmental effects on instrumenta-

tion in which solid active substances are listed and the effects of flora and fauna are briefly

mentioned.
Non-solid substances

Non-solid substances are only chemically active. They are therefore classified according to

the average and peak value of their concentration.
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SIST EN 60654-4:1998
654-4 © I E C 1987 — 11 —
4.1 Definitions
The following definitions are required to understand this part.
One-half hour mean value is defined as
1 h
x dt
'/2 h
where x is the measured or expected contaminant concentration.

Peak value is the maximum measured or expected one-half hour mean value recognized over

a year.

Mean value is the arithmetic mean of a statistically sufficient number of measured or

expected one-half hour mean values.
Note. — A one hour mean value may be used where legal.
5. Gases and vapours

The classes in Table I recognize that average concentrations and peak values shall both be

considered to properly classify an environment. Peak values have been integrated on a '/2 hour

basis. Chemical agents (e.g. SO 2 or HF) may vary greatly in their reactivity rate over a '/2

period. Therefore, the relationship of peak value to average value may vary with each

contaminant. The classification of environment by category should be determined by the

highest class if average and peak values are not in the same category. An alternate method

of classification based on copper reactivity rates is shown in Appendix B.
5.1 Contamination effects

Each site may have different combinations and concentration levels of corrosive gaseous

contaminants. Performance degradation can occur rapidly or over many years, depending on

the particular concentration levels and combinations present at a site. The following para-

graphs describe how various contaminants contribute to equipment performance degradation.

5.2 Inorganic chlorine compounds 2 in Table I)
(expressed as C1

This group contains both strong oxidants (chlorine, chlorine dioxide) and compounds such

as hydrogen chloride, so reactivity will depend upon the specific gas composition. In the

presence of moisture, these gases generate chloride ions which react readily with copper, tin,

silver and iron alloys. These reactions are significant even when the gases are present at low

levels. These reactions are attenuated in dry atmospheres. At higher concentrations, many

elastomers and some plastics are oxidized by exposure to chlorinated gases. Particular care

shall be given to equipment which is exposed to atmospheres which contain chlorinated

contaminants. Sources of chloride ions, such as cleaning compounds and cooling tower

vapours, etc., should be considered when classifying.
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SIST EN 60654-4:1998
654-4 © I E C 1987 — 13 —
5.2.1 Active sulphurs (expressed as H,S in Table I)

This group includes hydrogen sulphide, elemental sulphur and organic sulphur compounds

such as the mercaptans. When present at low levels, they rapidly attack copper, silver and iron

alloys. The presence of moisture and small amounts of inorganic chlorine compounds greatly

accelerates sulphide corrosion. Note, however, that attack still occurs in low relative humidity

environments. Active sulphurs rank alongside inorganic chlorides as the predominant cause

of atmospheric corrosion in the process industries.
5.2.2 (expressed as SO, in Table I)
Sulphur oxides

Oxidized forms of sulphur (SO 2, SO 3) are generated as combustion products of sulphur-

bearing fossil fuels. Low levels of sulphur oxides can passivate reactive metals and thus retard

corrosion. At higher levels they attack certain types of metals, elastomers and plastics. The

reactions with metals normally occur when these gases dissolve in water to form sulphurous

and sulphuric acid.
5.2.3 Nitrogen oxides (expressed as NO X in Table I)

NO X compounds (NO, NO„ N,O 4) are formed as combustion products of fossil fuels and

have a critical role in the formation of ozone in the atmosphere. They are also believed to have

a catalytic effect on corrosion of base metals by chlorides and sulphides. In the presence of

moisture, these gases form nitric acid which, in turn, attacks most common metals.

5.2.4 Hydrogen fluoride (expressed as HF in Table I)

This compound is a member of the halogen family and reacts like inorganic chloride

compounds.
5.2.5 Ammonia and derivatives (expressed as NH 3 in Table I)

Reduced forms of nitrogen (ammonia, amines, ammonium ions) occur mainly in fertilizer

plants, agricultural applications, and chemical plants. Copper and copper alloys are particu-

larly susceptible to corrosion in ammonia environments.
5.2.6 Photochemical species (expressed as 0 3 in Table I)

The atmosphere contains a wide variety of unstable, reactive species which are formed by

the reaction of sunlight with moisture and other atmospheric constituents. Some have lifetimes

measured in fractions of a second as they participate in rapid chain reactions. In addition to

ozone, a list of examples would include the hydroxyl radical as well as radicals of hydrocar-

bons, oxygenated hydrocarbons, nitrogen oxides, sulphur oxides and water. Because of the

transient nature of most of these species, their primary effect is on outdoor installations and

enclosures. In general, plastics and elastomers are more susceptible to photochemical effects

than metals.

Electrostatic precipitators in air-conditioning systems to buildings can generate ozone.

Note. —
Explanation of contaminant severity levels
5.3

There is a broad distribution of contaminant concentrations and reactivity levels existing

within industries using process measurement and control equipment. Some environments are

severely corrosive while others are mildly corrosive.
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SIST EN 60654-4:1998
654-4 © I E C 1987 - 15 -
5.3.1 Class 1: Industrial clean air

An environment sufficiently well controlled that corrosion is not a factor in determining

equipment reliability (refer to Table I for examples).
5.3.2 Class 2: Moderate contamination

An environment in which the effects of corrosion are measurable and may be a factor in

determining equipment reliability (refer to Table I for examples).
Class 3: Heavy contamination
5.3.3

An environment in which there is a high probability that corrosive attack will occur. These

harsh levels should prompt further evaluation resultin
...

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