Tests on electric and optical fibre cables under fire conditions—Part 12:Test for vertical flame propagation for a single insulated wire or cable—Procedure for 1 kW pre-mixed flame
Tests on electric and optical fibre cables under fire conditions-Part 12 : Test for vertical flame propagation for a single insulated wire or cable-Procedure for 1 kW pre-mixed flame
1 Scope
This document specifies the procedure for testing the resistance to vertical flame propagation for a single vertical electrical insulated conductor or cable, or optical fibre cable, under fire conditions. The apparatus is given in IEC 60332-1-1.
Note 1: Testing to this document may be performed simultaneously with that to GB/T 18380.13 if required.
Recommended requirements for performance are given in Annex A.
This document specifies the use of a 1 kW pre-mixed flame and is for general use, except that the procedure specified may not be suitable for the testing of small single insulated conductors or cables of less than 0.5 mm2 total cross-section because the conductor melts before the test is completed, or for the testing of small optical fibre cables because the cable is broken before the test is completed. In these cases, the procedure given in IEC 60332-2-2 is applicable.
Note 2: Since the use of insulated conductor or cable which retards flame propagation and complies with the recommended requirements of this standard is not sufficient by itself to prevent propagation of fire under all conditions of installation, it is recommended that wherever the risk of propagation is high, for example in long vertical runs of bunches of cables, special installation precautions shall also be taken. It cannot be assumed that because the sample of cable complies with the performance requirements recommended in this standard, that a bunch of cables will behave in a similar manner. (See GB/T 18380.31 - GB/T 18380.36).
2 Normative references
The following documents contain requirements which, through reference in this text, constitute provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition (including any amendments) applies.
IEC 60332-1-1 Tests on electric and optical fibre cables under fire conditions - Part 1-1 : Test for vertical flame propagation for a single insulated wire or cable - Apparatus
Note: GB/T 18380.11-2022 Tests on electric and optical fibre cables under fire conditions - Part 11:Test for vertical flame propagation for a single insulated wire or cable - Apparatus (IEC 60332-1-1:2015, IDT)
IEC 60811-203 Electric and optical fibre cables - Test methods for non-metallic materials - Part 203 : General tests - Measurement of overall dimensions
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
ignition source
source of energy that initiates combustion
[SOURCE: ISO 13943:2017, 3.219]
3.2
char
carbonaceous residue resulting from pyrolysis or incomplete combustion
[SOURCE: ISO 13943:2017, 3.47]
4 Test apparatus
The apparatus specified in IEC 60332-1-1 shall be used.
5 Procedure
5.1 Sample
The test sample shall be a piece of single insulated conductor or cable (600 ± 25) mm long.
The test sample diameter shall be measured using the method given in IEC 60811-203. The measurement shall be made at each of three places, separated by at least 100 mm.
The average of three measurements should be rounded to two decimal places and rounded to one decimal place as the outer diameter. If the calculation gives 9, 8, 7, 6, or 5 for the second decimal figure of the average value before rounding, raise the first to the next number; thus, for example, 5.75 is rounded to 5.8. If the calculation gives 0, 1, 2, 3, or 4 for the second decimal figure of the average value before rounding, maintain the first number; thus, for example, 5.74 is rounded to 5.7.
The overall diameter obtained shall be used for the selection of the time for flame application.
5.2 Conditioning
Before testing, all test pieces shall be conditioned at (23 ± 5) °C for not less than 16h at a relative humidity of (50 ± 20) %.
In the case of a single insulated conductor or cable with a finish of paint or lacquer, this conditioning shall follow an initial period where the test piece shall be kept at a temperature of (60 ± 2) °C for 4h.
5.3 Positioning of test piece
The test piece shall be straightened and secured to two horizontal supports by means of a suitable size of copper wire, in a vertical position in the centre of the metal enclosure, as described in IEC 60332-1-1, so that the distance between the bottom of the upper support and the top of the lower support is (550 ± 5) mm. In addition, the test piece shall be positioned so that the bottom of the specimen is approximately 50 mm from the base of the enclosure (see Figure 1).
The vertical axis of the test piece shall be arranged centrally within the enclosure (i.e. 150 mm from each side and 225 mm from the rear).
5.4 Flame application
Safety warning:
Precautions shall be taken to safeguard personnel against the following when conducting tests:
a) the risk of fire or explosion;
b) the inhalation of smoke and/or noxious products, particularly when halogenated materials are burned;
c) harmful residues.
5.4.1 Positioning of flame
A burner, as described in IEC 60332-1-1 , shall be ignited and the flow rates of gas and air adjusted to the specified values. The burner shall be positioned so that the tip of the blue cone impinges on the surface of the test piece at a distance of (475 ± 5) mm from the lower edge of the upper horizontal support, whilst the burner is at an angle of (45 ± 2)° to the vertical axis of the test piece (see Figure 2). The burner position shall be fixed throughout the flame application time.
Note: See Annex NA for the recommended gas and air flow rates.
For flat-form cables, the flame impingement shall be on the middle of the flat side of the cable.
In case of an electrical insulated conductor or cable, should the test piece move significantly during the test so as to render the result invalid, the test piece shall be held straight by the attachment of a load of approximately 5 N/mm2 of conductor area to the lower part of the sample so that the distance between the point where the load is attached and the lower edge of the top support measures (550 ± 5) mm. In such cases, the test piece shall not be secured to the lower support.
5.4.2 Test duration
Foreword I
Introduction V
1 Scope
2 Normative references
3 Terms and definitions
4 Principle
5 Reagents
6 Apparatus
7 Test procedure
8 Calculation and expression of results
9 Precision
Annex A (Informative) Identification method for elastomultiester
Annex B (Informative) Identification method for elastolefin
