SMOKE DETECTOR PLACEMENT IN COMPARTMENTS WITH HONEYCOMB CEILING A Numerical Study

One of the most interesting problems in fire detection system design is the problem referred to as detector position on a 'honeycomb ceiling', because beams and joists affect stratification of smoke and, consequently, smoke detector response time. The aim of this paper is to determine optimal smoke detector placement - on the underside of beams or on the structural slab in the cells. On the basis of rules of standards for smoke detector location, the large eddy simulation method of fire dynamics simulator software package was employed to investigate the effects of 'honeycomb'density on smoke detector response time. The simulation results show that the columns, beams, joists and similar structural elements affect stratification of smoke and, consequently, smoke detector response time. In the case when the honeycomb cells are small, the detectors on the underside of the beams react faster because the smoke does not enter the cells in sufficient quantity to activate the optical smoke detector located on the structural plate in the cells that form the beams. On the basis of the obtained results, a satisfactory solution for most possible situations that could occur in practice has been proposed.