3 Metre Cube Smoke Density Apparatus
IEC 61034; BS 6853; BS 6724; BS 7622
The 3 Metre Cube is used for measuring smoke emission when electric cables are burned under defined conditions (IEC 61034; BS 6853, BS 6724; BS 7622). An example would be a few cables burned horizontally. These units are produced to meet the specification used in many electric cable tests.
The equipment comprises of a cubic enclosure and a photometric system that can be supplied either in a self-assembly kit form or can be fully installed by FTT Engineers. The instrument is made of Zintec steel sheets and can be supplied with customised extraction facilities and all instrumentation, fans, stands and sample mounting frames. The photometric system has a horizontal optical path of 3m between two opposite faces of the cube and the attenuation of light transmitted through the chamber is measured during the test.
The 3 Metre Cube comprises of:
- 3 Metre Cube assembly
- Photometric system, stands, fans and sample mounting frames
- Extraction fan and ducting
- Chart Recorder or Windows Software
Features and Benefits:
- The enclosure is constructed from Zintec steel of 0.8mm thickness. The steel is fixed to a framework to enclose the unit. A door with a window that allows for observation is located at the front of the cube and is sealed at all appropriate joints.
- Sealed windows (100mm × 100mm) are provided in the two laterally opposed faces for the transmission of light from the horizontal photometric system (source and receiver). The windows centers are situated at a height of 2.15m on the cube.A photocell receiver is mounted at one end of a 150 +- 10mm tube and a dust protection window at the other end. The inside of the tube is matt black to minimise reflections.
- The signal from the photocell is proportional to the transmission of light and is recorded continuously, throughout the test, using a chart recorder or data acquisition system.
- The walls of the cube at floor level have orifices for atmospheric pressure equalisation. In order to avoid stratification of smoke, homogenisation is achieved by having a fan on the floor of the cube that blows horizontally throughout the course of the test.
- This method was developed for electric cables but it can also be adapted to materials, equipment and components.