NBR 11300 烟密度测试标准.pdf

NBR 11300 – Electric Cables and Wires under fire conditions Measurement of Smoke Density under burning defined conditions Method of test 1. Objective 1.1. This standard prescribes a test method for determining the density of smoke emitted by electric wires and cables, during burning, in test conditions defined, and not necessarily the same as those that occur in fires. 1.2. The density of the smoke is an important aspect in analyzing the behavior of electric wires and cables in the presence of fire because it’s directly related to the evacuation of the public reached the site and the access to this for fire fighting. 1.3. The measurement of the density of smoke emitted is based on the signal provided by a photometric system. 1.4. Samples used are made of wires or cables complete in order to bring the test results to real situations. 1.5. This standard allows comparing the behavior of different types of wires or cables, or check if a wire or electric cable meets the requirements of applicable standard. 1.6. This test must be satisfactorily performed, so that the combination of camera and optical system generate consistent results comparing other cameras with identical wires and cables burned under the same conditions. 3. Definitions 3.1. Transmittance Fraction of light energy that passes through a column of solution. 3.2. Absorbance Co-logarithm of solution transmittance, optical density. 4. Equipment 4.1. Test chamber 4.1.1 The chamber must have a cubic form, edge (inner side) equal to (3000 ± 30) mm with profiled steel structure, and walls, roof and floor of a suitable material under test conditions. One wall should contain an access door with a glass window for visual inspection. Two other windows sealed transparent, with minimum dimensions of 100 mm x 100 mm must be provided on opposite walls to allow the transmission of a light beam from the horizontal photometric system. The distance from the floor to the center of these t