Abstract
Aim: The aim of this paper is to carry out an experimental test of the influence of wooden materials on the activation time of two types of optical beam smoke detectors – the OSID and the DOP 6001 – during flaming and non-flaming combustion.
Introduction: Over the years, there have been many types of fire detector that differ in the way they operate. A few years ago, it was discovered that many detector types depended on the operation principle. The simplest detectors were temperature detectors, at first mechanical, and then, with the development of technology, also electronic. It was obvious that they did not detect the threat fast enough, so it was essential to find solutions that would respond to the first signs of a developing fire. Spot-type smoke detectors are easy to install and use because they are a complete, self-contained devices. Their effectiveness decreases as the distance between the source of combustion and the location of smoke detectors grows. In some buildings, e.g. large warehouses or industrial plants, for a better fire-safety level, there is a need to install dozens of spot-type smoke detectors to protect large areas. In such cases optical beam smoke detectors could be the best practical solution.
Methodology: The article is based on a series of experimental tests in a test chamber with various sources of flaming and non-flaming combustion. Two different types of optical beam smoke detectors were used to test the influence of wooden beams on activation times.
Conclusions: During the experiments with non-flaming combustion, intense smoke production started immediately after the initiation of the combustion process. The non-flaming phenomenon was a very stable process for all kinds of tested wood. The activation-time results of optical beam smoke detectors and the evolution of the operational parameters, which was almost linear, indicate that these types of detectors are more effective for non-flaming combustion, as opposed to flaming combustion. Flaming combustion starts with a small flame of burning alcohol, which can initiate the combustion of wood. The burning rate and the intensity of smoke production increased, causing a linear evolution of operation parameters from tested smoke detectors over time. The suppression of light beams emitted by the transmitter of the OSID detectors shows different evolution depending on the type of combustion. Smoke production from non-flaming combustion initially suppresses both light beams. After some delay, the effect of the differences between UV and IR suppression is observed. During flaming combustion, the difference is immediately apparent and clearly increases with the development of the test fire.
Keywords: optical beam smoke detectors, wood combustion, fire detection
Type of article: original scientific article