BSI PD IEC TS 60079-42:2019
$142.49
Explosive atmospheres – Electrical Safety Devices for the control of potential ignition sources from Ex-Equipment
Published By | Publication Date | Number of Pages |
BSI | 2019 | 28 |
This part of IEC 60079, which is a Technical Specification, provides guidance for equipment manufacturers where electrical safety devices are used to reduce the likelihood of potential ignition sources becoming effective in Ex Equipment located in Explosive Atmospheres. Electrical safety devices perform a safety function to control potential ignition sources from both, electrical or non-electrical Ex Equipment in explosive atmospheres.
This document may also be applied to a combination of elements performing a safety function.
For example:
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Sensor
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Logic system
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Final element
This Technical Specification can also be used for assessing the safety device independently, without being designed for a specific Ex Equipment.
A safety device can be a measure to achieve a required EPL of the Ex Equipment with respect to a potential ignition source. The combination of the safety device and the Ex Equipment could then comply with the relevant standards of the IEC 60079 series and the ISO 80079 series with respect to the Equipment Protection Level. However, increasing the EPL of Ex Equipment by the simple addition of a safety device is not within the scope of this document.
This document does not apply to:
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mechanical control equipment such as pressure relief valves, mechanical governors and other mechanical safety devices
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the use of gas detection
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control equipment to prevent the occurrence of explosive atmospheres, e.g. inerting systems and ventilation systems
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mitigation of an explosion
NOTE Some potential ignition sources might not be practicably controlled by safety devices.
Electrical safety devices, where the level of safety integrity is identified under other parts of the IEC 60079 series, this document can be used as a reference for the realization of the level of safety integrity.
Electrical safety devices may be installed either as part of or separate to the Ex Equipment under control (EEUC) and may be located inside or outside the hazardous area.
PDF Catalog
PDF Pages | PDF Title |
---|---|
2 | undefined |
4 | English CONTENTS |
6 | FOREWORD |
8 | INTRODUCTION |
9 | 1 Scope |
10 | 2 Normative references 3 Terms and definitions 4 Basic requirements |
11 | 5 Ignition prevention by safety devices 5.1 General concept of ignition risk reduction 5.2 Safety characteristics of a safety device Tables Table 1 – Minimum RRF for a safety device for ignition risk reduction |
12 | 5.3 Associated safety device 6 Functional requirements for a safety device 6.1 General requirements 6.2 Specification of the safety function 6.3 Requirements for achieving the safety integrity 6.3.1 Simple safety devices |
13 | 6.3.2 Complex safety device 7 Testing and verification 7.1 Type tests 7.2 Proof tests 8 Marking 9 Instructions |
15 | Annex A (informative)Guidance for assessment of a simple safety device Table A.1 – Relationship between λd and RRF |
16 | Annex B (informative)Examples for the application of safety devices B.1 General B.2 Ex Equipment with a temperature controlled surface B.2.1 Problem: B.2.2 Consequence: B.2.3 Solution: |
17 | B.3 Current-dependent safety device for thermal protection of motors with type of protection Ex eb B.3.1 Problem: B.3.2 Consequence: B.3.3 Solution: Figures Figure B.1 –Safety device to limit the temperature rise |
18 | B.4 Risk reduction by ignition control and mitigation, bucket elevator example B.4.1 Problem Figure B.2 – Overload protection device to limit the temperature rise of a motor under stall and overload conditions |
19 | B.4.2 Ignition Hazard Assessment B.4.3 Safety controls to prevent ignition Figure B.3 – Bucket elevator principle |
20 | B.4.4 Safety Controls with explosion mitigation Figure B.4 – Bucket elevator sensors for ignition hazard detection |
21 | B.5 Control of high temperatures B.5.1 Problem B.5.2 Ignition hazard assessment Figure B.5 – Controls with explosion mitigation |
22 | B.5.3 Safety controls |
23 | Annex C (informative)Use of the Safe Motor Temperature (SMT) sub-function with converter-fed motors C.1 General Figure C.1 – Overview |
24 | C.2 Reliability of the safety motor temperature control function. C.3 Control without temperature sensors C.4 Control with temperature sensors Figure C.2 – Control without temperature sensors Table C.1– SMT safety sub function Risk Reduction Factors (RRF) |
25 | Figure C.3 – Control with temperature sensors |
26 | Bibliography |