Industrial-process control - Safety of analyzer houses (IEC 61285:2015)

This International Standard describes the physical requirements for the safe operation of the
process analyser measuring system installed in an analyser house (AH) in order to ensure its
protection against fire, explosion and health hazards. This standard applies for analyser
houses with inner and/or external potential explosive atmospheres and it applies to hazards
caused by toxic substances or asphyxiant gases. (Refer to national guidelines on toxic
hazards.)
This standard does not address facilities where solids (dust, powder, fibres) are the hazard.
This standard does not seek to address all functional safety issues related to analyser
houses.
Clause 4 addresses the location of the AH and connection within the process plant areas.
Clause 5 addresses the design, construction and layout of the AH. It does not address parts
of the analyser measuring system installed in other locations such as sample conditioning
rooms (SCR) or switchgear rooms.
Clause 6 addresses measures for reducing the danger of explosion for AHs while permitting
maintenance of equipment with the power on and the case open.
For most fluids, the major constraint is that the concentration of vapours, which are toxic for
personnel, is lower than the lower explosive (flammable) limit (LEL) (see Clause 7).
Using n-Pentane as an example, the LEL is 1,4 % or 14 000 × 10–6, the level immediately
dangerous to life or health (which is the maximum level from which a worker could escape
within 30 min without any escape-impairing symptoms or any irreversible health effects) is
only 0,5 % or 5 000 × 10–6.
Clause 7 addresses those measures for protecting personnel from materials in the
atmosphere of AHs that are hazardous to health.

Prozessautomatisierung - Sicherheit von Analysengeräteräumen (IEC 61285:2015)

Commande des processus industriels - Sécurité des bâtiments pour analyseurs (IEC 61285:2015)

L'IEC 61285:2015 décrit les exigences physiques requises pour un fonctionnement sûr du système de mesure constitué par l'analyseur de processus installé dans un bâtiment pour analyseur (AH) afin d'assurer la protection contre les dangers d'incendie, d'explosion et les dangers pour la santé. La présente norme s'applique aux bâtiments pour analyseurs à atmosphères intérieures et/ou extérieures potentiellement explosives et s'applique aux dangers dus aux substances toxiques ou aux gaz asphyxiants. Cette troisième édition annule et remplace la deuxième édition parue en 2004. Elle constitue une révision technique. Les principales modifications sont:
- incorporation du corrigendum paru précédemment et
- mises à jour mineures de plusieurs sections et références.

Nadzor industrijskih procesov - Varnost prostorov za analiziranje (IEC 61285:2015)

Ta mednarodni standard opisuje fizikalne zahteve za varno upravljanje sistema za analiziranje, ki je nameščen v prostoru za analiziranje (AH), da je zagotovljena zaščita pred požari, eksplozijami in nevarnostmi za zdravje. Ta standard velja za prostore za analiziranje z notranjimi in/ali zunanjimi potencialno eksplozivnimi atmosferami ter tveganja, povezana s strupenimi snovmi ali zadušljivimi plini. (Glej nacionalne smernice o toksičnih nevarnostih.)
Ta standard ne zajema objektov, pri katerih so tveganje trdne snovi (prah, prašek, vlakna). Ta standard ni namenjen obravnavi vseh vprašanj funkcionalne varnosti, povezanih s prostori za analiziranje.
Točka 4 obravnava mesto prostora za analizo in povezavo znotraj območij obdelovalnega obrata.
Točka 5 obravnava zasnovo, konstrukcijo in ureditev prostora za analizo.
Standard ne obravnava delov sistema za merilne analize, nameščenih na drugih lokacijah, kot so prostori za pripravo vzorcev (SRC) ali prostori za stikalne naprave.
Točka 6 obravnava ukrepe za zmanjšanje možnosti eksplozije v prostorih za analizo z omogočanjem vzdrževanja opreme z vklopljenim napajanjem in odprtim pokrovom.
Glavna ovira pri večini tekočin je dejstvo, da je koncentracija hlapov, ki so strupeni za osebje, nižja od spodnje meje eksplozivnosti (vnetljivosti) (LEL) (glej točko 7).
Če kot primer vzamemo n-pentan, pri katerem je spodnja meja eksplozivnosti 1,4 % ali 14.000 × 10–6, je raven, ki je takoj življenjsko nevarna ali nevarna za zdravje (kar je maksimalna raven, pri kateri lahko delavec uide v 30 min brez simptomov, ki bi ovirali pobeg, ali trajnih učinkov na zdravje) samo 0,5 % ali 5.000 × 10–6.
Točka 7 obravnava ukrepe za zaščito osebja pred materiali in atmosferami prostorov za analize, ki so nevarni za zdravje.

General Information

Status
Published
Publication Date
26-Jul-2015
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
14-May-2015
Due Date
19-Jul-2015
Completion Date
27-Jul-2015

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SLOVENSKI STANDARD
SIST EN 61285:2015
01-september-2015

Nadzor industrijskih procesov - Varnost prostorov za analiziranje (IEC 61285:2015)

Industrial-process control - Safety of analyzer houses (IEC 61285:2015)
Prozessautomatisierung - Sicherheit von Analysengeräteräumen (IEC 61285:2015)
Commande des processus industriels - Sécurité des bâtiments pour analyseurs (IEC
61285:2015)
Ta slovenski standard je istoveten z: EN 61285:2015
ICS:
25.040.40 Merjenje in krmiljenje Industrial process
industrijskih postopkov measurement and control
SIST EN 61285:2015 en

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

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SIST EN 61285:2015
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SIST EN 61285:2015
EUROPEAN STANDARD EN 61285
NORME EUROPÉENNE
EUROPÄISCHE NORM
April 2015
ICS 13.110; 25.040.40 Supersedes EN 61285:2004
English Version
Industrial-process control - Safety of analyzer houses
(IEC 61285:2015)

Commande des processus industriels - Sécurité des Prozessautomatisierung - Sicherheit von

bâtiments pour analyseurs Analysengeräteräumen
(IEC 61285:2015) (IEC 61285:2015)

This European Standard was approved by CENELEC on 2015-03-31. 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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,

Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, 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: Avenue Marnix 17, B-1000 Brussels

© 2015 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.

Ref. No. EN 61285:2015 E
---------------------- Page: 3 ----------------------
SIST EN 61285:2015
EN 61285:2015 - 2 -
Foreword

The text of document 65B/954/FDIS, future edition 3 of IEC 61285, prepared by SC 65B

"Measurement and control devices", of IEC/TC 65 "Industrial-process measurement, control and

automation" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as

EN 61285:2015.
The following dates are fixed:
(dop) 2015-12-31
• latest date by which the document has to be implemented at
national level by publication of an identical national
standard or by endorsement
(dow) 2018-03-31
• latest date by which the national standards conflicting with
the document have to be withdrawn
This document supersedes EN 61285:2004.

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

patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such

patent rights.
Endorsement notice

The text of the International Standard IEC 61285:2015 was approved by CENELEC as a European

Standard without any modification.
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SIST EN 61285:2015
- 3 - EN 61285:2015
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

The following documents, in whole or in part, are normatively referenced in this document and are

indispensable for its application. For dated references, only the edition cited applies. For undated

references, the latest edition of the referenced document (including any amendments) applies.

NOTE 1 When 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 60079-0 (mod) 2011 Explosive atmospheres -- Part 0: EN 60079-0 2012
Equipment - General requirements
- - +A11 2013
IEC 60079-10-1 2008 Explosive atmospheres -- Part 10-1: EN 60079-10-1 2009
Classification of areas - Explosive gas
atmospheres
IEC 60079-20-1 2010 Explosive atmospheres - Part 20-1: EN 60079-20-1 2010
Material characteristics for gas and vapour
classification - Test methods and data
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SIST EN 61285:2015
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SIST EN 61285:2015
IEC 61285
Edition 3.0 2015-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Industrial-process control – Safety of analyser houses
Commande des processus industriels – Sécurité des bâtiments pour analyseurs
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 13.110; 25.040.40 ISBN 978-2-8322-2228-7

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
---------------------- Page: 7 ----------------------
SIST EN 61285:2015
– 2 – IEC 61285:2015 © IEC 2015
CONTENTS

FOREWORD ........................................................................................................................... 4

INTRODUCTION ..................................................................................................................... 6

1 Scope .............................................................................................................................. 7

2 Normative references ...................................................................................................... 7

3 Terms and definitions ...................................................................................................... 8

4 Location of AHs and connection within the process plant areas ..................................... 11

4.1 General ................................................................................................................. 11

4.2 Response time ...................................................................................................... 11

4.3 Utilities ................................................................................................................. 11

4.4 Safety ................................................................................................................... 11

4.4.1 Location ........................................................................................................ 11

4.4.2 Escape .......................................................................................................... 11

4.4.3 Area classification ......................................................................................... 11

4.4.4 Peripheral hazards ........................................................................................ 11

4.5 Access .................................................................................................................. 11

5 Design, construction and layout of AHs ......................................................................... 12

5.1 General ................................................................................................................. 12

5.2 General requirements ........................................................................................... 12

5.3 Dimensions and layout .......................................................................................... 12

5.4 Structural requirements ......................................................................................... 12

5.4.1 Construction materials ................................................................................... 12

5.4.2 Walls ............................................................................................................. 13

5.4.3 Floors and foundation .................................................................................... 13

5.4.4 Doors ............................................................................................................ 13

5.4.5 Windows ........................................................................................................ 13

5.4.6 Roof .............................................................................................................. 13

5.5 Equipment ............................................................................................................ 13

5.5.1 Lighting ......................................................................................................... 13

5.5.2 Communications ............................................................................................ 13

5.5.3 Piping, tubing and valves ............................................................................... 13

5.5.4 Utilities .......................................................................................................... 14

5.5.5 Fire extinguishers .......................................................................................... 14

5.5.6 Ventilation ..................................................................................................... 14

5.5.7 Temperature .................................................................................................. 15

5.6 Labelling/instructions/documentation .................................................................... 15

5.6.1 Entrance ........................................................................................................ 15

5.6.2 Alarms ........................................................................................................... 15

5.6.3 Safety procedures ......................................................................................... 15

5.6.4 Additional data............................................................................................... 16

6 Explosion protection of AHs ........................................................................................... 16

6.1 General ................................................................................................................. 16

6.2 General requirements ........................................................................................... 16

6.3 Protection of AHs against explosion hazards by means of artificial ventilation ....... 16

6.3.1 Classification ................................................................................................. 16

6.3.2 Requirements for AHs where the explosion hazard originates externally ........ 17

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SIST EN 61285:2015
IEC 61285:2015 © IEC 2015 – 3 –
6.3.3 Requirements for AHs where the explosion hazard originates from

internal gases or vapours .............................................................................. 17

6.3.4 Requirements for AHs where the explosion hazard originates from

internal liquids ............................................................................................... 18

6.3.5 Requirements for AHs where the explosion hazard originates from any

combination of the above ............................................................................... 19

6.4 Protection of AHs against explosion hazards by means of natural ventilation ........ 19

6.4.1 General ......................................................................................................... 19

6.4.2 Ventilation requirements ................................................................................ 19

6.4.3 Heating requirements .................................................................................... 20

6.4.4 Gas detectors ................................................................................................ 20

7 Measures to prevent health hazards to personnel in AHs ............................................... 20

7.1 General ................................................................................................................. 20

7.2 Guidelines ............................................................................................................ 20

7.3 General requirements ........................................................................................... 20

7.4 Safety measures ................................................................................................... 21

7.5 External hazards ................................................................................................... 22

7.6 Additional measures for abnormal working conditions ........................................... 22

7.7 Labelling/instructions/documentation .................................................................... 23

Annex A (normative) Leakage risk of modules in the AH ...................................................... 24

A.1 General ................................................................................................................. 24

A.2 Modules with negligible leakage risk ..................................................................... 24

A.3 Modules with limited leakage risk .......................................................................... 24

A.3.1 General ......................................................................................................... 24

A.3.2 Guidance for evaluating modules ................................................................... 25

Bibliography .......................................................................................................................... 26

Table A.1 – Module evaluation .............................................................................................. 25

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SIST EN 61285:2015
– 4 – IEC 61285:2015 © IEC 2015
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
INDUSTRIAL-PROCESS CONTROL –
SAFETY OF ANALYSER HOUSES
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.

International Standard IEC 61285 has been prepared by subcommittee 65B: Measurement

and control devices, of IEC technical committee 65: Industrial-process measurement, control

and automation.

This third edition cancels and replaces the second edition published in 2004. This edition

constitutes a technical revision.
The main changes with respect to the previous edition are listed below:
a) incorporation of previously issued corrigendum;
b) minor updates to several sections and references.
---------------------- Page: 10 ----------------------
SIST EN 61285:2015
IEC 61285:2015 © IEC 2015 – 5 –
The text of this standard is based on the following documents:
FDIS RVD
65B/954/FDIS 65B/966/RVD

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

voting indicated in the above table.

This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

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

the stability date indicated on the IEC website under "http://webstore.iec.ch" in the data

related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
---------------------- Page: 11 ----------------------
SIST EN 61285:2015
– 6 – IEC 61285:2015 © IEC 2015
INTRODUCTION

Process analysers measure the characteristics of a process stream continuously and

automatically. The process sample is introduced automatically and the system is designed for

unattended operation and minimal maintenance.

The placement of devices for process analysis in analyser houses is beneficial for technical

and economic reasons:
– in order to facilitate appropriate environmental conditions;
– to simplify servicing and maintenance issues;
– to enable the use of a common infrastructure (see 3.5).

This document is designed to set forth minimum safety requirements for typical analyser

houses (AHs). It is superseded in all cases by national, local, or corporate requirements, if

other or more stringent requirements will apply.
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SIST EN 61285:2015
IEC 61285:2015 © IEC 2015 – 7 –
INDUSTRIAL-PROCESS CONTROL –
SAFETY OF ANALYSER HOUSES
1 Scope

This International Standard describes the physical requirements for the safe operation of the

process analyser measuring system installed in an analyser house (AH) in order to ensure its

protection against fire, explosion and health hazards. This standard applies for analyser

houses with inner and/or external potential explosive atmospheres and it applies to hazards

caused by toxic substances or asphyxiant gases. (Refer to national guidelines on toxic

hazards.)

This standard does not address facilities where solids (dust, powder, fibres) are the hazard.

This standard does not seek to address all functional safety issues related to analyser

houses.

Clause 4 addresses the location of the AH and connection within the process plant areas.

Clause 5 addresses the design, construction and layout of the AH. It does not address parts

of the analyser measuring system installed in other locations such as sample conditioning

rooms (SCR) or switchgear rooms.

Clause 6 addresses measures for reducing the danger of explosion for AHs while permitting

maintenance of equipment with the power on and the case open.

For most fluids, the major constraint is that the concentration of vapours, which are toxic for

personnel, is lower than the lower explosive (flammable) limit (LEL) (see Clause 7).

Using n-Pentane as an example, the LEL is 1,4 % or 14 000 × 10 , the level immediately

dangerous to life or health (which is the maximum level from which a worker could escape

within 30 min without any escape-impairing symptoms or any irreversible health effects) is

only 0,5 % or 5 000 × 10 .
Clause 7 addresses those measures for protecting personnel from materials in the
atmosphere of AHs that are hazardous to health.
2 Normative references

The following documents, in whole or in part, are normatively referenced in this document and

are indispensable for its application. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60079-0:2011, Explosive atmospheres – Part 0: General requirements

IEC 60079-10-1:2008, Explosive atmospheres – Part 10-1: Classification of areas – Explosive

gas atmospheres

IEC 60079-20-1:2010, Explosive atmospheres – Part 20-1: Material characteristics for gas

and vapour classification – Test methods and data
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SIST EN 61285:2015
– 8 – IEC 61285:2015 © IEC 2015
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
analyser cabinet
small housing in which analysers are installed individually or grouped together

Note 1 to entry: Maintenance is performed from outside the cabinet with the door(s) open.

3.2
analyser shelter

structure with one or more sides open and free from obstruction to the natural passage of air,

in which one or more analysers are installed

Note 1 to entry: The maintenance of the analysers is normally performed in the protection of the shelter.

3.3
analyser house

enclosed building or part of a building containing process analysers and associated

equipment where streams for analysis are brought in and which is regularly entered by

authorized personnel

Note 1 to entry: An AH is not a permanent workplace. Within the scope of this standard, the term AH is used

regardless of the structure configuration as either a room, a walk-in cabinet, an analyser container or an analyser

building and whether or not it is an integral part of, or attached to, another structure.

3.4
sample conditioning room
SCR

room that is separated from the AH and has modules for sample conditioning, auxiliary

material, or sample disposal equipment
3.5
infrastructure

required means and supply with auxiliaries to operate an AH with all equipment therein, for

example, instrument air, nitrogen, water, power supply, incidental disposal of waste and

disposal of substances introduced to be analysed

Note 1 to entry: The infrastructure occasionally comprises the fundament of an AH, the positioning of gas bottles

and containers for gas supply and test gases. The infrastructure comprises in addition the ventilation and

climatisation of the AH and the needed alarm devices within and outside of the AH.

3.6
maintenance

servicing, inspection, repair, improvement and weakness analysis of process analyser devices

and infrastructure
3.7
toxic substances

gaseous or liquid substances that, if released in a room, will cause a health hazard by contact

with the skin or by inhalation from the surrounding atmosphere
3.8
safety back-up

additional personnel, in constant contact with a person or persons in hazardous working

condition, who could assist or call for additional help
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SIST EN 61285:2015
IEC 61285:2015 © IEC 2015 – 9 –
3.9
external explosion hazard

hazard existing when the AH is erected at a location where flammable substances may

ingress from the outside resulting in dangerous concentrations of flammable gases and

vapours inside the AH
3.10
internal explosion hazard

hazard existing when a flammable mixture can result from release of samples or auxiliary

supplies inside the AH
3.11
lower explosive limit
LEL

volume ratio of the flammable gas or vapour in air below which an explosive gas atmosphere

will not be formed
3.12
explosive gas atmosphere

mixture with air, under atmospheric conditions, of a flammable material in the form of gas or

vapour in which, after ignition, combustion spreads through the unconsumed mixture

3.13
hazardous area

area in which an explosive gas atmosphere is present, or may be expected to be present, in

quantities such as to require special precautions for the construction, installation and use of

devices
3.14
non-hazardous area

area in which an explosive gas atmosphere is not expected to be present in quantities such as

to require special precautions for the construction, installation and use of the analysers

3.15
zone 0

area in which an explosive gas atmosphere is present continuously or for long periods or

frequently
[SOURCE: IEC 60079-10-1:2008, 3.6]
3.16
zone 1

area in which an explosive gas atmosphere is likely to occur in normal operation occasionally

[SOURCE: IEC 60079-10-1:2008, 3.7]
3.17
zone 2

area in which an explosive gas atmosphere is not likely to occur in normal operation but, if it

does occur, will persist for a short period only
[SOURCE: IEC 60079-10-1:2008, 3.8]
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SIST EN 61285:2015
– 10 – IEC 61285:2015 © IEC 2015
3.18
source of release

a point or location from which a gas, vapour, mist or liquid may be released into the

atmosphere so that an explosive gas atmosphere could be formed
[SOURCE: IEC 60079-10-1:2008, 3.9]
3.19
grades of release

there are three basic grades of release, as listed below in order of decreasing frequency and

likelihood of the explosive gas atmosphere being present:
a) continuous grade;
b) primary grade;
c) secondary grade.

A source of release may give rise to any one of these grades of release, or to a combination

of more than one
[SOURCE: IEC 60079-10-1:2008, 3.10]
3.20
continuous grade of release

release which is continuous or is expected to occur frequently or for long periods

[SOURCE: IEC 60079-10-1:2008, 3.11]
3.21
primary grade of release

release which can be expected to occur periodically or occasionally during normal operation

[SOURCE: IEC 60079-10-1:2008, 3.12]
3.22
secondary grade of release

release which is not expected to occur in normal operation and, if it does occur, is likely to do

so only infrequently and for short periods
[SOURCE: IEC 60079-10-1:2008, 3.13]
3.23
release rate

quantity of flammable gas, vapour or mist emitted per unit time from the source of release

[SOURCE: IEC 60079-10-1:2008, 3.14]
3.24
flashpoint

lowest liquid temperature at which, under certain standardized conditions, a liquid gives off

vapours in a quantity such as to be capable of forming an ignitable vapour/air mixture

3.25
ignition temperature
T-rating
value of ignition temperature as given in IEC 60079-20-1
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SIST EN 61285:2015
IEC 61285:2015 © IEC 2015 – 11 –
3.26
equipment protection level
EPL

level of protection assigned to equipment based on its likelihood of becoming a source of

ignition and distinguishing the differences between explosive gas atmospheres, explosive dust

atmospheres, and the explosive atmospheres in mines susceptible to firedamp
[SOURCE: IEC 60079-0:2011, 3.26]
3.27
containment system

parts within the room or building containing the hazardous substance that may constitute an

internal source of release
4 Location of AHs and connection within the process plant areas
4.1 General

When determining the location of the AH, the following factors should be considered.

4.2 Response time

Line lengths from sample points to the analysers shall be estimated and the necessary flow

rates calculated to determine whether resultant dead times, samp
...

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