IEC 60695-11-11:2021 pdf download

IEC 60695-11-11:2021 pdf download.Fire hazard testing – Part 11-11: Test flames – Determination of the characteristic heat flux for ignition from a non-contacting flame source
1 Scope
This part of IEC 60695 describes a test method used to determine the characteristic heat flux for ignition (CHFI) from a non-contacting flame source for materials used in electrotechnical products, sub-assemblies or their parts. It provides a relationship between ignition time and incident heat flux. A test specimen cut from an end-product or sub-assembly can be tested by this test method. This part of IEC 60695 can be used in the fire hazard assessment and fire safety engineering procedures described in IEC 60695-1-10, IEC 60695-1-11 and IEC 60695-1-12. This basic safety publication is intended for use by technical committees in the preparation of standards in accordance with the principles laid down in IEC Guide 104 and ISO/IEC Guide 51. One of the responsibilities of a technical committee is, wherever applicable, to make use of basic safety publications in the preparation of its publications. The requirements, test methods or test conditions of this basic safety publication will not apply unless specifically referred to or included in the relevant publications.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IEC 60695-1-10, Fire hazard testing – Part 1-10: Guidance for assessing the fire hazard of electrotechnical products – General guidelines IEC 60695-1-11, Fire hazard testing – Part 1-11: Guidance for assessing the fire hazard of electrotechnical products – Fire hazard assessment IEC 60695-1-12, Fire hazard testing – Part 1-12: Guidance for assessing the fire hazard of electrotechnical products – Fire safety engineering IEC 60695-4, Fire hazard testing – Part 4: Terminology concerning fire tests for electrotechnical products IEC 60695-11-4, Fire hazard testing – Part 11-4: Test flames – 50 W flame – Apparatus and confirmational test method IEC GUIDE 104, The preparation of safety publications and the use of basic safety publications and group safety publications ISO/IEC Guide 51, Safety aspects – Guidelines for their inclusion in standards
4 Principle of the test
The incident heat flux, Q, is measured using the apparatus described in 5.3 and 5.4. The incident heat flux is controlled by the distance, D, between the top of the burner tube and the lower surface of the test specimen and by the flow rate of fuel gas to the burner (See Annex A). The time required to ignite the test specimen is measured as a function of the incident heat flux. The tests are performed at different levels of incident heat flux until the maximum heat flux, at which the average ignition time t ig is greater than 120 s, is obtained. This maximum heat flux is defined as the characteristic heat flux for ignition (CHFI). The incident heat flux values at which the tests are carried out are chosen within the range of 30 kW/m 2 to 75 kW/m 2 and shall be integral multiples of 5 kW/m 2 .
5 Apparatus
5.1 Test arrangement The arrangement of the apparatus and the position of the test specimen and burner are shown in Figure 1. The test specimen and masking board shall be mounted horizontally. The burner tube shall be mounted vertically. The centre of the test specimen, the burner tube, the sensor of the heat flux meter and the conical hole in the masking board shall all be aligned vertically. The sensor of the heat flux meter shall be placed horizontally 6 mm above the upper surface of the masking board with its sensing surface facing down, i.e. the sensing surface of the heat flux meter is placed in the horizontal plane where the lower surface of the test specimen is placed.