- Author
- Meacham, B. J.
- Title
- Characterization of Smoke From Burning Materials for the Evaluation of Light Scattering Type Smoke Detector Response.
- Coporate
- Worcester Polytechnic Institute, MA
- Report
- Thesis, May 1991, 174 p.
- Keywords
- smoke detectors | light scattering detectors | detector response | smoldering | fire detection | smoke detection | optical density | smoke chambers | data analysis | instruments
- Identifiers
- data collection; experimental procedures
- Abstract
- Experiments were performed to characterize smoke produced from smoldering materials using light scattering theory. A prototype instrument was developed to measure the intensity of light scattered by smoke particles at various angles for this purpose. The instrument was constructed using technology similar to that found in currently manufactured light scattering type smoke detectors. A Gallium Arsenide solid-state laser was used as the source, with photodiodes used as scattered light receivers. A smoke chamber was constructed in which experiments were performed. In addition to the scattered light detection instrument (SLDI), two commercially available lgith scattering type smoke detectors and instrumentation which provided obscuration and relative particle concentration were used. To evaluate to operation of the SLDI, experiments were performed using a test aerosol of known optical properties; average particle size, refractive index and particle concentration. Experimental data from the SLDI indicated general agreement with results calculated using Mie scattering theory. Smoke from smoldering wood, paper, cotton and rubber was then analyzed. Four different fuel positions were utilized for these tests. Data obtained from the SLDI indicates that the highest intensity of scattered light detected is at the most forward angle, and the intensity of light scattered at a given angle changes as the fuel changes. This data also suggests that the effects of coagulation and particle concentration on the intensity of light scattered is fuel dependant and may be related to the refractive index of the smoke particles. Experimental data obtained from the SLDI appears to be consistent with Mie scattering theory, suggesting that smoke can be characterized using light scattering theory. A possible method for evaluating and predicting the response of light scattering type smoke detectors to smoldering combustion based on detector design parameters and light scattering characteristics of smoke is discussed.