LED Smoke Density Photometric System

The FTT ‘Smoke Density Photometric System’ (based on DIN 50055 and ISO 3182) is designed to be used in conjunction with equipment that measures smoke from burning materials. The unit can be fitted to several instruments such as the Room/Corner Test (ISO 9705), Single Burning Item (SBI) (EN 13823), Heat Release and Smoke Production Apparatus for Cables (EN 50399), UL 9540A, Flooring Radiant Panel (EN ISO 9239-1), etc. Der Apparat besteht aus:

• Lichtquelle
• Lichtmesssystem
• Steuergerät

New LED replaces halogen lamp: The Light Source has traditionally been a halogen gas filled tungsten filament lamp, however that has become obsolete, with no direct replacement found. The technical specifications of ISO/TS 19850 provide a methodology for comparing traditional white light systems with new LED lighting to confirm they can be used as an alternative. FTT has developed a new LED white light source and has demonstrated that the difference between the LED and Halogen systems are statistically insignificant. The new FTT LED system was tested in accordance with ISO/TS 19850. Tests for drift and noise, optical filter checks and response times show that the new LED white light source has a similar (if not better) performance to the legacy halogen system. Smoke tests in an SBI following Method B of ISO/TS 19850 show that the difference between the results from LED and halogen systems for s1, s2 and s3 is statistically insignificant. New System/Upgrade: FTT ‘s newly developed LED white light system is housed in the same sized unit as the halogen filament source and therefore physically fits into the same support system. Power for the system is provided by a new power supply complete with a LED drive unit. Das Lichtmessgerät hat folgende Komponenten:

• Achromatisches System von Linsen
• Photoelektrische Siliziumzelle
• Verstärker mit hoher Verstärkung und geringem Rauschen

These components are housed in an assembly with a collimating lens. The signal from the Light-Measuring Device is taken to the Control Unit then to software, capable of continuously measuring relative light intensity against time as percentage transmission over the ranges to be studied. The system has a linear response with respect to transmittance and an accuracy of better than ±1.5% of the maximum reading. An analogue voltage output from the Control Unit (for transmission) can be taken to a data acquisition unit built directly into the FTT gas analysis rack for large-scale calorimeters (including the SBI, EN 50399, Room/Corner Test and UL 9540A) and Flooring Radiant Panel. A standalone Windows based software package is also available to enable simple data acquisition, analysis and storage via a data acquisition system.