Yoshikazu Minegishi

Experimental Study of Crowd Flow Passing through Simple-shaped Room and Validation for an Evacuation Simulator

This paper describes the characteristics of crowd flow passing through simple-shaped rooms and to validate an evacuation simulation model called “SimTread”. It presents experiments on crowd flow with 43 subjects and intends to quantify the aspects of crowd flow in simple rooms. Recently, for estimating evacuation of buildings on fire, several computer simulation models have been developed and applied. However, human evacuation data-sets for validating simulation are scarce. The results of this study show that pedestrian flow rate at the opening changes depending on the density of the space connected. Flow rate rises if the opening is connected to larger space, which is less dense and, in result, increases speed of pedestrians. For validating an evacuation simulator, evacuation data from actual building fires are too complex for proving the equivalence. Therefore, we carried out the experiments of crowed flow passing through simpleshaped rooms, and compared experimental data with our simulation results. There was a good agreement between the result of experiments and simulations. The differences were less than 10%.

Model Experiment and CFD Analysis on a Solar Assisted Ventilation System

abstract A prototype atrium building is suggested with a large solar chimney on top of the atrium, which is expected to promote natural smoke exhaust and accumulate smoke at a event of a fire and promote natural ventilation when outdoor climate is desirable. In this paper natural ventilation efficiency is evaluated. The solar chimney is similar to conventional chimneys except the south-facing wall is replaced by a glazing. Solar radiation transmits the glass and thermal energy is stored in the other three walls. Air in the chimney is heated and by stack effect natural ventilation is realized. Experiment is conducted on a 1/25 scale model to evaluate the efficiency of this solar assisted natural ventilation system. Several area conditions of inlet and outlet are chosen while other conditions keep the same. CFD simulation is simultaneously done. According to results of model experiment and simulation, natural ventilation promoted by the solar chimney is quite sufficient to meet the demands of atrium ventilation. As to the office rooms, if area is properly set, fresh air requirement can be satisfied only by natural ventilation. In the case of this study, when inlet area changes to 24m2, necessary ventilation rate can be obtained.

Modelling pedestrian merging in stair evacuation in multi-purpose buildings

Abstract Despite the total evacuation time of occupants in a multi-storey building not being affected by pedestrian merging on stairs, the calculation of evacuation times in each individual floor depends on the pedestrian merging ratio. In fact, different merging ratios may cause an evacuation to take place from the top to the bottom or vice versa. A simplified simulation model for the calculation of evacuation time at each floor is presented here. This model allows the investigation of the impact of two main variables affecting the evacuation time at each floor, namely 1) different initial numbers of pedestrians at each floor (i.e. occupant load), and 2) different merging ratios at each floor. This means that the model allows the calculation of the evacuation time at each floor considering a building with different occupancy types at different floors (e.g. office, residential, commercial, etc.) and different merging ratios which may be caused by a different configuration of the landing door at each floor. The model is presented in this paper using a case study of a hypothetical building. A detailed discussion on the model assumptions, advantages and limitations is also provided.

Performance-Based Fire Safety Design for a Skyscraper: A Case in Japan

The performance-based design of evacuation safety for high-rise complexes and its verification are presented in this chapter. In the design process, three points of view were mainly considered: prevention of or from a city fire, control of the fire and the spread of smoke, and egress plans under bad scenarios. To prevent fire spreading to or from the neighborhood, buffers were installed at the connections to other facilities. In addition, in the high-rise complex, some buffers were installed to prevent fire spreading across the tenants (occupants) and to limit the number of evacuees who have to escape. Other buffers, called safe waiting areas, were prepared for queuing evacuees. On verification, all the rooms in the entire building were certified on the basis of performance. Available safe egress times (ASETs) were mainly estimated by smoke spread from a αt2 design fire. The atrium was verified by two-layer zone model simulations. The pressurizing system of the staircases was verified by smoke movement simulation with a network zone model.

Prediction of evacuation from a large-scale assembly facilities applying multi-agent model: Validation study of pedestrian simulation system simtread in practical use

The purpose of this paper is to examine the prediction performance and practical usability of Multi-agent pedestrian simulation system. As an example, evacuation flow of about 10000 people from large-scale assembly facilities is simulated. Major results are as follows: 1) At the seats lined up orthogonally to the aisle, farther seats from egress of aisle remains to the last; 2) At the point two pedestrians flow merges, the flow become more densely; 3) In case flow become densely, if there is extra space, pedestrians expand the walking area and decrease density to walk by maximum speed. Those features are described quite obviously as movies and a lot of perceptions are acquired which cannot be acquired by conventional evacuation calculation methods.