Abstract of Special Research Report (SRR-No.29)
National Institute of Occupational Safety and Health, Japan
A Study on the Prevention of Explosion and Fires for Recycle Industries (Midterm Report)
: With the recent promotion of the conservation of energy and resources and reduction of waste, more materials are being recycled. Some aspects of recycling, however, are dangerous, and frequent incidents of explosion, fire, and poisoning have been reported. These hazards are attributed largely to the increase in the amount and types of recycled substances, the replacement of chlorofluorocarbons with liquefied petroleum gas, which is done to protect the ozone layer and to ward off global warming, and the use of flammable cleaning liquids instead of nonflammable ones in an effort to reduce environmental pollution.
Measurements of Droplet Size for Calculating Reaction Heat in a Liquid-Liquid Heterogeneous Reaction Process
: Some explosions, which occurred in heterogeneous liquid-liquid reaction processes, have been reported. In such processes, reactants need to be mixed well by mechanical agitation for smooth progress of the reactions. And the unsuitable control for the mixing is the most frequent cause for runaway situation.
The Dust Explosion of Aluminum Dust in Water Vapor
|Teruhito OTSUKA and Haruhiko ITAGAKI|
: The popular fire-extinguisher is the water. However, some kinds of metals, which have higher oxidation-reduction potential than hydrogen, can react with and get oxygen from water. In this study, aluminum powder is employed to evaluate the reactivity with water. Aluminum is one of the metal used most in the world, especially for electronic device's case as aluminum-magnesium alloy.
Survey of Explosions / Fires by Portable Liquefied Gas Cylinder and the Ignition Experiment
|Haruhiko ITAGAKI and Ou-sup HAN|
: Concern for recycling of the people and the industry rises. But, explosions / fires often happened in the recycling industry due to the increase in the explosion / fire hazard of the recycle materials. This research paid attention to the explosion / fire which happened due to the portable liquefied gas cylinder and the spray can for the purpose of the safe handling in the people and the recycling industry.
Field Study on Explosion Protection
in the Bulky Refuse Crushing Process Facilities
: In a daily life, the disposal of garbage and industrial waste is a serious problem. The legal system for proper disposal of refuse and promotion of the recycling has been enforced in order to promote the formation of a recycling society in Japan. Though explosion or fire has often occurred in the bulk refuse crushing process facilities, the problem is caused by the stop of the machine which causes further accidents for the smooth citizen life. In addition, there can be the accidents involving a new type of explosion and fire which is related to the development of the new refuse resource recycling technology. The final objective of this study will be made to develop a practical explosion protection/suppression system, which can be applied to the bulk refuse crushing process facilities. In order to obtain a useful knowledge for the prevention of explosion and fire in the process facilities, a field study was carried out in 7 municipal facilities in the different district (Yamagata, Miyagi, Saitama, Tokyo, Gifu, Mie, and Nara) and 2 recycling facilities for household electric appliances (Tokyo and Chiba). Gas explosion and fire are, in the most cases, caused by spray can, gas cartridge, and small cylinder including liquefied petroleum gas. Hot surfaces in the crusher and sparks by the impact, etc. seem to be the ignition source. In most investigated facilities, injection systems of air or steam are adopted in order to prevent the explosion in the crusher. Attention is necessary for not only gas explosions but also dust explosions. These dangerous objects should be directly removed by visual observation and camera monitoring, so that dangerous objects such as the LP gas cylinder as a cause of the explosion may not enter the crusher. Automatic explosion suppression systems as an explosion protective measure have not introduced, since installation and maintenance costs are expensive, until it widely installed. To begin with, an appropriate explosion pressure relief vent should be installed, as an explosion protection system.