BS EN 60079-28:2015 – TC:2020 Edition
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Tracked Changes. Explosive atmospheres – Protection of equipment and transmission systems using optical radiation
| Published By | Publication Date | Number of Pages |
| BSI | 2020 | 106 |
IEC 60079-28:2015 is available as /2 which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition. IEC 60079-28:2015 specifies the requirements, testing and marking of equipment emitting optical radiation intended for use in explosive atmospheres. It also covers equipment located outside the explosive atmosphere or protected by a Type of Protection listed in IEC 60079-0, but which generates optical radiation that is intended to enter an explosive atmosphere. It covers Groups I, II and III, and EPLs Ga, Gb, Gc, Da, Db, Dc, Ma and Mb. This standard does not cover ignition by ultraviolet radiation and by absorption of the radiation in the explosive mixture itself. Explosive absorbers or absorbers that contain their own oxidizer as well as catalytic absorbers are also outside the scope of this standard. This second edition cancels and replaces the first edition, published in 2006, and constitutes a technical revision. Refer to the Foreword of the document for a complete listing of the technical changes between edition 2.0 and previous edition of the document. Keywords: equipment emitting optical radiation intended for use in explosive atmospheres
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 67 | English CONTENTS |
| 69 | FOREWORD |
| 73 | INTRODUCTION |
| 74 | 1 Scope |
| 75 | 2 Normative references 3 Terms and definitions |
| 78 | 4 General requirements 5 Types of protection 5.1 General Tables Table 1 – EPLs achieved by application of types of protection for optical systems |
| 79 | 5.2 Requirements for inherently safe optical radiation “op is” 5.2.1 General 5.2.2 Continuous wave radiation |
| 80 | Table 2 – Safe optical power and irradiance for Group I and II equipment, categorized by Equipment Group and temperature class Table 3 – Safe optical power and irradiance for Group III equipment |
| 81 | Table 4 – Safe limit values for intermediate area, Group I or II, constant power, T1 – T4 atmospheres, equipment Groups IIA, IIB or IIC (Data derived from Figure B.1 including a safety factor) |
| 83 | 5.2.3 Pulsed radiation |
| 84 | 5.2.4 Ignition tests 5.2.5 Over-power/energy fault protection |
| 85 | 5.3 Requirements for protected optical radiation “op pr” 5.3.1 General 5.3.2 Radiation inside optical fibre or cable |
| 86 | 5.3.3 Radiation inside enclosures 5.4 Optical system with interlock “op sh” |
| 87 | 6 Type verifications and tests 6.1 Test set-up for ignition tests 6.1.1 General 6.1.2 Test vessel Figures Figure 1 – Optical ignition delay times and safe boundary curve with safety factor of 2 |
| 88 | 6.1.3 Criteria to determine ignition 6.2 Verification of suitability of test set-up for type tests 6.2.1 Reference gas 6.2.2 Reference absorber 6.2.3 Reference test for continuous wave radiation and pulses above 1 s duration 6.2.4 Reference test for pulsed radiation below 1 ms pulse duration |
| 89 | 6.3 Type tests 6.3.1 Ignition tests with continuous wave radiation and pulses above 1 s duration 6.3.2 Ignition tests with single pulses less than 1 ms duration 6.3.3 Tests for pulse trains and pulses from 1 ms to 1 s duration 6.3.4 Absorber targets for type tests |
| 90 | 6.3.5 Test acceptance criteria and safety factors 7 Marking |
| 92 | Annex A (informative) Reference test data Table A.1 – Reference values for ignition tests with a mixture of propane in air at 40 °C mixture temperature |
| 93 | Annex B (informative) Ignition mechanisms |
| 95 | Table B.1 – AIT (auto ignition temperature), MESG (maximum experimental safe gap) and measured ignition powers of the chosen combustibles for inert absorbers as the target material (α1 064 nm=83 %, α805 nm=93)3 |
| 96 | Figure B.1 – Figure B.1 – Minimum radiant igniting power with inert absorber target (α1064 nm=83 %, α805 nm=93 %) and continuous wave-radiation of 1064 nm |
| 97 | Figure B.2 – Minimum radiant igniting power with inert absorber target (α1 064 nm=83 %, α805 nm=93 %) and continuous wave-radiation (PTB: 1064 nm, HSL: 805 nm, [8]: 803 nm) for some n-alkanes Table B.2 – Comparison of measured minimum igniting optical pulse energy (Qe,p i,min) at 90 μm beam diameter with auto ignition temperatures (AIT) and minimum ignition energies (MIE) from literature [9] at concentrations in percent by volume (ϕ) |
| 98 | Annex C (normative) Ignition hazard assessment Figure C.1 – Ignition hazard assessment |
| 100 | Annex D (informative) Typical optical fibre cable design Figure D.1 – Example Multi-Fibre Optical Cable Design For Heavy Duty Applications Figure D.2 – Typical Single Optical Fibre Cable Design |
| 101 | Annex E (normative) Flow diagram for the assessment of pulses Figure E.1 – Flow diagram for the assessment of pulses according to 5.2.3 |
| 102 | Bibliography |
