IEC 61034-1-2019 pdf download.Measurement of smoke density of cables burning under defined conditions – Part 1: Test apparatus.
3 Terms and definitions For the purposes of this document, the terms and definitions in IEC 60695-4 apply, or if a term is not defined in IEC 60695-4 then the definition in ISO/IEC 1 3943 applies.
4Details of test enclosure The equipment shall comprise a cubic enclosure with inside dimensions of 3 000 mm ± 30 mm and constructed of a suitable material fixed on to a steel angle frame. One side shall have a door, with a glass inspection window. Transparent sealed windows (minimum size 1 00 mm × 1 00 mm) shall be provided on two opposite sides to permit the transmission of a beam of light from the horizontal photometric system. The distance from the floor to the centre of these windows shall be 2 1 50 mm ± 1 00 mm (see Figure 1 for plan view).
The walls of the enclosure shall include orifices at ground level (i.e. not greater than 1 00 mm above the level of the chamber floor) for the passage of cables, etc., and to permit the enclosure to be at atmospheric pressure. No orifice shall be directly behind the fire source or on the same wall. A minimum of two orifices shall be provided and the total area of the orifices open during the test shall be 50 cm 2 ± 1 0 cm 2 .
NOTE 1 Two orifices, each with an area of 25 cm² ± 5 cm², and located on two opposite walls, one under the light source and one under the receiver have been found to be suitable.
The ambient temperature outside the enclosure shall be 20 °C ± 1 0 °C and the enclosure shall not be directly exposed to sunlight or extreme climatic changes.
NOTE 2 It should normally be possible to extract fumes from the enclosure after each test through a duct complete with valve which should be closed during the test. The duct may include a fan to increase the rate of extraction. It is recommended that the door of the enclosure be opened to assist the extraction process. A draught screen, 1 500 mm ± 50 mm long and 1 000 mm ± 50 mm high, shall be placed in the enclosure, at the position shown in Figure 1 . It shall abut on the back wall (with a maximum gap of 1 0 mm) at a point 750 mm ± 25 mm from the side wall, and shall be curved to intersect the centre line of the enclosure at a point 1 400 mm ± 25 mm from the point of abutment.
5 Photometric system
5.1 The photometric system is illustrated in Figure 2.The light source and the receiver shall be placed opposite each other externally, in the centre of windows in two opposite walls of the cube , as shown in Figures 1 and 2. The light beam shall traverse the cube through the glass windows in the side walls.
5.2 The light source shall be a halogen lamp with a tungsten filament with a clear quartz
bulb having the following characteristics:
nominal power: 1 00 W;
nominal voltage: 1 2 V d.c.;
nominal luminous flux: 2 000 lm to 3 000 lm;
nominal colour temperature: 2 800 K to 3 200 K.
The bulb shall be supplied with a voltage of 1 2,0 V ± 0,1 V (mean value). During the test, the voltage shall be stabilized to a range of ± 0,01 V (see A.2c) for additional guidance.) The lamp shall be mounted in a housing and the beam adjusted by a lens system to give an evenly illuminated circular area of 1 ,5 m ± 0,1 m diameter on the interior of the opposite wall.
5.3 The receptor photocell shall be of the selenium or silicon type with a spectral response matching the International Commission on Illumination (CIE) photopic observer (equivalent to the human eye). The photocell shall be mounted at the end of 1 50 mm ± 1 0 mm tube with a dust protection window at the other end. The inside of the tube shall be matt black to prevent reflections. The photocell shall be connected to a potentiometric recorder to produce a linear proportional output. The cell shall be resistance-loaded to operate in its linear range and the input impedance of the recorder shall be at least 1 0 4 times greater than the load resistance of the cell which shall not exceed 1 00 Ω.
5.4 The photometric system shall be energized before the blank test. When stability has been attained, the zero and full scale reading of the recorder shall be adjusted for light on the detector corresponding to 0 % (absence of light) and 1 00 % luminous transmission. NOTE 1 Periodically, for example at the beginning of a test series, the performance of the photocell should be verified by placing standard neutral density filters in the light beam. It is essential that these filters cover the entire optical port of the photocell and the values of transmittance measured by the photocell give a value of parameter A A m (defined in 1 0.5) within ± 5 % of the calibrated value of the filter. The filters should also permit the verification of the linearity of response of the detector which should be proportional to the transmittance of light in the range used. NOTE 2 Most neutral density filters are designated according to a parameter defined as absorbance which is the same as the parameter A defined in 1 0.5 which may be used to convert measured transmittance.IEC 61034-1 pdf download.