EN ISO 21789:2022

SLOVENSKI STANDARD
01-december-2022
Uporaba plinske turbine - Varnost (ISO 21789:2022)
Gas turbine applications - Safety (ISO 21789:2022)
Gasturbinenanwendungen - Sicherheit (ISO 21789:2022)
Applications des turbines à gaz - Sécurité (ISO 21789:2022)
Ta slovenski standard je istoveten z: EN ISO 21789:2022
ICS:
27.040 Plinske in parne turbine. Gas and steam turbines.
Parni stroji Steam engines
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 21789
EUROPEAN STANDARD
NORME EUROPÉENNE
October 2022
EUROPÄISCHE NORM
ICS 27.040
English Version
Gas turbine applications - Safety (ISO 21789:2022)
Applications des turbines à gaz - Sécurité (ISO Gasturbinenanwendungen - Sicherheit (ISO
21789:2022) 21789:2022)
This European Standard was approved by CEN on 24 June 2022.

CEN 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 CEN
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 CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2022 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 21789:2022 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
Annex ZA (informative) Relationship between this European Standard and the essential
requirements of Directive 2006/42/EC aimed to be covered . 4
Annex ZB (informative) Relationship between this European Standard and the essential
requirements of EU Directive 2014/34/EU . 6
European foreword
This document (EN ISO 21789:2022) has been prepared by Technical Committee ISO/TC 192 "Gas
turbines" in collaboration with Technical Committee CEN/TC 399 “Gas Turbines applications - Safety”
the secretariat of which is held by BSI.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by April 2023, and conflicting national standards shall be
withdrawn at the latest by April 2023.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document has been prepared under a Standardization Request given to CEN by the European
Commission and the European Free Trade Association, and supports essential requirements of EU
Directive(s) / Regulation(s).
For the relationship with EU Directive(s) / Regulation(s), see informative Annex ZA and ZB, which is an
integral part of this document.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 21789:2022 has been approved by CEN as EN ISO 21789:2022 without any modification.

Annex ZA
(informative)
Relationship between this European Standard and the essential
requirements of Directive 2006/42/EC aimed to be covered
This European Standard has been prepared under a Commission’s standardization request “M/396
Mandate to CEN and CENELEC for Standardisation in the field of machinery" to provide one voluntary
means of conforming to essential requirements of Directive 2006/42/EC of the European Parliament
and of the Council of 17 May 2006 on machinery and amending Directive 95/16/EC (recast).
Once this standard is cited in the Official Journal of the European Union under that Directive,
compliance with the normative clauses of this standard given in Table ZA.1 confers, within the limits of
the scope of this standard, a presumption of conformity with the corresponding essential requirements
of that Directive, and associated EFTA regulations.
Table ZA.1 — Correspondence between this European Standard and Annex I
of Directive 2006/42/EC
The relevant Essential Clause(s)/sub-clause(s) of this EN Remarks/Notes
Requirements of Directive
2006/42/EC
1.1.2 5.1, 5.2, 5.5, 5.8, 7.5.2, 7.6.2, 7.7.1
1.1.3 5.23.8.4, 5.24.3, 7.7.8
1.1.4 5.14, 5.15.9, 7.6.4
1.1.5 5.8.5
1.1.6 5.20.3
1.2.2 5.20.2, 5.20.8, 7.6.4
1.2.4.1 5.20.8
1.2.4.3 5.20.8
1.2.4.4 5.20.8
1.2.6 5.20.4, 5.20.8, 5.21.9.2, 5.21.2, 7.7.3
1.3.1 5.8.5, 7.7.1
1.3.2 5.8.3, 5.8.9, 5.8.15.1, 5.23.10, 7.5
1.3.3 5.8, 5.20.7, 7.7
1.3.7 5.8.1, 7.7.2
1.4.1 5.8.1.1, 5.8.2
1.4.2.1 5.8.1
1.4.3  Not covered
1.5.1 5.20, 5.21
1.5.2 5.21.3, 7.4
1.5.3 5.10, 5.21.2, 5.23.8.5, 5.24.3, 5.24.4, 7.7.3
1.5.4 5.8.12, 5.23.8, 7.7.2
1.5.5 5.8.1.2, 5.8.3, 5.8.9, 5.9.3, 5.13.5, 5.16.3
1.5.6 5.15
1.5.7 5.16
1.5.8 5.7
1.5.10 5.20.2
1.5.11 5.15.10, 5.21.6
1.5.13 5.10.5.8, 5.10.6, 5.10.9, 7.7.8
1.5.14 5.13.8, 5.13.9, 5.18.1, 7.6.2, 7.6.4, 7.7.1,
7.8
1.5.15 5.8.2
1.5.16 5.21.5
1.6.2 5.8.2, 7.7
1.6.3 5.21.2.1, 7.7.3
1.6.4 5.2, 5.21, 5.23
1.7.1 7.2, 7.8
1.7.1.1 5.20.3, 7.2
1.7.1.2 5.15.8, 5.20.3, 5.20.8, 7.5.1, 7.7.1, 7.8
1.7.2 5.2, 7.3, 7.8
1.7.3 6.2, 7.8
1.7.4 7.2
1.7.4.1 7
1.7.4.2 7
1.7.4.3 7.1
WARNING 1 — Presumption of conformity stays valid only as long as a reference to this European
Standard is maintained in the list published in the Official Journal of the European Union. Users of this
standard should consult frequently the latest list published in the Official Journal of the European
Union.
WARNING 2 — Other Union legislation may be applicable to the product(s) falling within the scope of
this standard.
Annex ZB
(informative)
Relationship between this European Standard and the essential
requirements of EU Directive 2014/34/EU
This European Standard has been prepared under a mandate given to CEN by the European
Commission and the European Free Trade Association to provide a means of conforming to Essential
Requirements of the New Approach Directive 2014/34/EU.
Once this standard is cited in the Official Journal of the European Union under that Directive and has
been implemented as a national standard in at least one Member State, compliance with the clauses of
this standard given in Table ZB.1 confers, within the limits of the scope of this standard, a presumption
of conformity with the corresponding Essential Requirements of that Directive and associated EFTA
regulations.
Table ZB.1 — Correspondence between this European Standard and Directive 2014/34/EU
Clause(s)/sub-clause(s) of this EN Essential Requirements Qualifying remarks/Notes
of Directive
5.1 A
5.16, 5.16.4, 5.17 1.0.1
5.1, 5.4, 7.5.2 1.0.2
5.1, 5.20.2 1.0.4
5.9.5, 5.16.1 1.0.5
5.4, 5.9.7, 5.16, 7.1, 7.4, 7.5, 7.5.2, 7.7, 1.0.6
7.7.1, 7.7.4, 7.11
5.16.4 1.1.1
5.18.3 1.1.2
5.8.9 1.1.3
5.5 1.2.1
5.3 1.2.2
5.8.3, 5.10.6.6, 5.10.9, 5.22, 5.23.8.4 1.2.3
5.17.7 1.2.4
5.20.2 1.2.5
7.7.1 1.2.6
5.8.1.2, 5.8.6, 5.16.4.3, 5.21.8 1.2.7
5.20.7 1.2.8
5.16.5.3.3 1.2.9
5.16.5.3.2 1.3.1
5.21.3 1.3.2
5.21.3.3 1.3.3
5.18.3 1.3.4
5.1, 5.20.2 1.4.1
5.20.2 1.4.2
5.20.4, 5.20.8, 5.23.9.1 1.5.1
5.8.18, 5.20.4 1.5.2
5.20.8 1.5.3
5.20.3 1.5.4
5.1 1.5.5
5.20.5 1.5.6
5.19.3 1.5.7
5.20.4 1.5.8
5.20.8 1.6.1
5.20.8 1.6.2
5.21.9 1.6.3
5.19 1.6.5
5.16.4, 5.16.5, 5.17 2.2.1.1
5.13.4, 5.20.2 2.2.1.2
5.8.2, 5.8.18 2.2.1.3
5.16.4, 5.16.5, 5.17 2.3.1.1
5.13.4, 5.20.2 2.3.1.2
WARNING 1 — Presumption of conformity stays valid only as long as a reference to this European
Standard is maintained in the list published in the Official Journal of the European Union. Users of this
standard should consult frequently the latest list published in the Official Journal of the European
Union.
WARNING 2 — Other Union legislation may be applicable to the product(s) falling within the scope of
this standard.
INTERNATIONAL ISO
STANDARD 21789
Second edition
2022-07
Gas turbine applications — Safety
Applications des turbines à gaz — Sécurité
Reference number
ISO 21789:2022(E)
ISO 21789:2022(E)
© ISO 2022
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
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Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
ISO 21789:2022(E)
Contents Page
Foreword .vii
Introduction .viii
1 Scope . 1
2 Normative references . 2
3 Terms and definitions . 4
4 List of significant hazards . 6
5 Safety requirements. 6
5.1 General . 6
5.2 Risk assessment . 6
5.2.1 Risk assessments requirements . 7
5.2.2 As low as reasonably practical . . 8
5.3 Modifications and replacement parts . 8
5.4 Foreseeable misuse . 8
5.5 Lifetime . 8
5.6 Hazard combinations . 8
5.7 Noise reduction at design stage . 8
5.8 Mechanical . 9
5.8.1 Guarding . 9
5.8.2 Accessibility for maintenance. 9
5.8.3 Casing design . 10
5.8.4 Gas turbine compressor surge . 10
5.8.5 Stability and handling . . 10
5.8.6 Overload of couplings, rotating shafts and gears due to torque . 11
5.8.7 Vibration . 11
5.8.8 Mechanical failure caused by corrosion . 11
5.8.9 Design methods and materials . 11
5.8.10 Gas turbine temperatures .12
5.8.11 Environmental loads . .12
5.8.12 Assembly features .12
5.8.13 Couplings . 12
5.8.14 Rotor bearings .12
5.8.15 Rotating part failure .12
5.8.16 Foreign object damage (FOD) screen . 13
5.8.17 Gearbox . 13
5.8.18 Starting systems . 13
5.8.19 Low ambient temperature conditions . 14
5.9 Gas turbine compressor air inlet system . 14
5.9.1 General . 14
5.9.2 Inlet air contamination . 14
5.9.3 Icing monitoring and prevention . 14
5.9.4 Implosion protection .15
5.9.5 Inlet explosion protection . 15
5.9.6 Waste disposal through combustion . 16
5.9.7 Recirculation . . 16
5.9.8 Gas turbine compressor air inlet ducting . 16
5.10 Fuel systems . 17
5.10.1 General . 17
5.10.2 Fuel supply quality and supply conditions . 17
5.10.3 Pressure (leakage) testing. 17
5.10.4 Fuel supply heating . 17
5.10.5 Gas fuel systems . . 17
5.10.6 Liquid fuel systems . 21
iii
ISO 21789:2022(E)
5.10.7 Multi-fuel systems .25
5.10.8 Fuel purging . 25
5.10.9 Fuel drainage . 26
5.11 Combustion supervision .26
5.11.1 General . 26
5.11.2 Requirements for ignition . 26
5.11.3 Extinction safety time . 27
5.12 Exhaust system . 27
5.12.1 Damper controls . 27
5.12.2 Flexible joint location . 27
5.12.3 Exhaust outlet . 27
5.12.4 Explosion protection. 27
5.13 Enclosures.28
5.13.1 General .28
5.13.2 Enclosure structure .29
5.13.3 Enclosure fire precautions .29
5.13.4 Explosion prevention and protection — Area classification — Ventilation .29
5.13.5 Gas detection .29
5.13.6 Enclosure purging .30
5.13.7 Flammable mist .30
5.13.8 Access and doors . 30
5.13.9 Entrapment. 31
5.14 Lighting . 31
5.15 Fire precautions . 31
5.15.1 General . 31
5.15.2 Structural fire risk reduction . 31
5.15.3 Flammable fluids mitigation and containment . 31
5.15.4 Fire protection . 32
5.15.5 Fire detection . 32
5.15.6 Fire extinguishing systems . 33
5.15.7 Water mist extinguishant .34
5.15.8 Extinguishing system controls .34
5.15.9 Escape .36
5.15.10 Uncontrolled release of media and loss of propellant pressure .36
5.15.11 Vessel thermal relief (burst disc) .36
5.15.12 Propellant vessels . 36
5.15.13 Release of extinguishant into gas turbine halls, control rooms, etc. .36
5.16 Hazardous area classification and explosion prevention and protection . 37
5.16.1 General . 37
5.16.2 Area classification . 37
5.16.3 Explosion prevention . . 37
5.16.4 Avoidance or reduction of effective ignition sources .38
5.16.5 Reduction of explosion effects in an enclosed space .39
5.17 Ventilation . 41
5.17.1 General . 41
5.17.2 Cooling . 41
5.17.3 Heating . 41
5.17.4 Hazardous area control . 41
5.17.5 Hot surfaces . 41
5.17.6 Ventilation inlet location . 42
5.17.7 Ventilation inlet filtration . 42
5.17.8 Ventilation inlet ducting . 42
5.17.9 Ventilation outlet location. 42
5.17.10 Ventilation monitoring . 42
5.18 Fans . 43
5.18.1 Fan guards and structural failure. 43
5.18.2 Air blast oil coolers . . 43
5.18.3 Sparking of fan blades . 43
iv
ISO 21789:2022(E)
5.19 Flammable gas detection . 43
5.19.1 Type / selection principles . 43
5.19.2 Location principles . 43
5.19.3 Settings .44
5.19.4 Enclosures containing hot surfaces — Screening tool .44
5.19.5 Maintenance and calibration .44
5.20 Control and automatic protection systems .44
5.20.1 General .44
5.20.2 Environmental suitability . 45
5.20.3 Ergonomics . 45
5.20.4 Failure . 45
5.20.5 Calibration . . . 45
5.20.6 Testing . 45
5.20.7 Speed control .46
5.20.8 Gas turbine emergency shutdown system .46
5.20.9 Interlocks . 47
5.20.10 Cyber security . 47
5.21 Electrical . 47
5.21.1 Design/Installation . 47
5.21.2 Isolation and stored energy . 47
5.21.3 Electrostatic energy and bonding .48
5.21.4 Water ingress .48
5.21.5 Lightning .49
5.21.6 Electromagnetic compatibility (EMC) .49
5.21.7 Battery installations .49
5.21.8 Electrical overload .49
5.21.9 Electrical power failure .49
5.22 Drains, vents and bleeds . 50
5.22.1 General .50
5.22.2 Vents for flammable gases .50
5.22.3 Toxic and hazardous emissions .50
5.22.4 Gas turbine compressor bleeds . 51
5.23 Pressure equipment . 51
5.23.1 General . 51
5.23.2 Design . 51
5.23.3 Hazards . 51
5.23.4 Misuse . 51
5.23.5 Handling and operation . 51
5.23.6 Isolation, draining and venting . 52
5.23.7 Fluid injection . 52
5.23.8 Assemblies . 52
5.23.9 Safety accessories . .54
5.23.10 Flexible piping (and metal hoses) .54
5.23.11 External fire .55
5.23.12 Material embrittlement and corrosion . 55
5.23.13 Ultra-violet (UV) resistant pipework. 55
5.24 Auxiliary systems . 55
5.24.1 Lubrication systems . 55
5.24.2 Water systems .56
5.24.3 Hydraulic and pneumatic systems .56
5.24.4 Utility air supplies .56
5.25 Installation in a hazardous area .56
5.26 Unenclosed gas turbines in a hall. 57
5.27 Decommissioning and disposal .58
6 Compliance verification .58
6.1 Quality assurance .58
6.2 Verification of safety requirements .58
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ISO 21789:2022(E)
7 Information for use .58
7.1 General .58
7.2 Language . 59
7.3 Packaging . 59
7.4 Commissioning . 59
7.5 Operation .60
7.5.1 General .60
7.5.2 Safety instructions and emergency procedures .60
7.6 Enclosure access . 61
7.6.1 General . 61
7.6.2 Risk assessment for accessing enclosures . 62
7.6.3 Limitations under operational conditions. 62
7.6.4 Limitations under non-operational conditions . 62
7.
...