Tests on electric and optical fibre cables under fire conditions - Part 34: Test for vertical flame spread of vertically-mounted bunched wires or cables - Category B
1 Scope
Parts 31, 32, 33, 34, 35 and 36 of GB/T 18380 specifies a method of test for the evaluation of vertical flame spread of vertically mounted bunched wires or cables, electrical or optical, under defined conditions.
Note: For the purpose of this standard, the term ‘electric wire or cable’ covers all insulated metallic conductor cables used for the conveyance of energy or signals.
The test is intended for type approval testing. The requirements for the selection of cables for testing are given in Annex A. The flame spread is measured as the extent of damage of the cable sample. This procedure may be used to demonstrate the cable’s ability to limit flame spread.
This part of GB/T 18380 covers category B and relates to cables installed on the test ladder to achieve a nominal total volume of non-metallic material of 3.5 L/m of test sample. The flame application time is 40 min. The method of mounting uses the front of the standard ladder. The category is intended for general use where medium volumes of non-metallic material are required to be evaluated.
A recommended performance requirement is given in Annex B.
2 Normative References
The following normative documents contain provisions which, through reference in this text, constitute provisions of this part of GB/T 18380. For dated references, subsequent amendments (excluding corrections), or revisions, of any of these publications do not apply to this part. However parties to agreements based on this part are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies.
GB/T 2951.13-2008 Common Test Methods for Insulating and Sheathing Materials of Electric and Optical Cables - Part 13: Methods for General Application - Measurement for Determining the Density - Water Absorption Tests - Shrinkage Test (IEC 60811-1-3: 1993, IDT)
GB/T 16499-1996 Guide to the Drafting of Electrical Safety Standards (eqv IEC Guide 104: 1984)
GB/T 18380.31-2008 Test on Electric and Optical Fibre Cables Under Fire Conditions - Part 31: Test for Vertical Flame Spread of Vertically-mounted Bunched Wires or Cables – Apparatus (IEC 60332-3-10: 2000, IDT)
IEC 60695-4: 1993 Fire Hazard Testing - Part 4: Terminology Concerning Fire Test
3 Definitions
For the purpose of this part of GB/T 18380 the following definitions apply. The definitions are taken from IEC 60695-4: 1993.
3.1
ignition source
source of energy that initiates combustion
Foreword i
1 Scope
2 Normative References
3 Definitions
4 Test Apparatus
5 Test Procedure
6 Evaluation of Test Results
7 Performance Requirements
8 Retest Procedure
9 Test Report
Annex A (Normative) Guidance on Cable Selection for Type Approval Testing
Annex B (Informative) Recommended Performance Requirements
Annex C (Informative) Simple Calculation Method for the Number of Test Sample
