Abstract of Special Research Report (RR-85)
National Institute of Occupational Safety and Health, Japan
Explosion Characteristics of Mixtures with Air of Propane, Ethylene or Hydrogen --With Special Reference to Testing Method for Flameproof Enclosure of Electrical Apparatus--
RR-85-1 |
Toshihiro HAYASHI, Ryuji TANAKA and Katsuhiro SAKANUSHI |
: Explosion characteristics of mixtures with air of propane, ethylene or hydrogen are studied in three cylindrical vessels of the same length/diameter ratio. The flammable mixtures are ignited at one end of each vessel, and the maximum explosion pressure attained (P m), the time to attain the maximum pressure (t m) and the average rate of pressure rise (P m/t m) are determined for a wide range of flammable content under atmospheric pressure ; further tests are carried out under elevated pressure conditions for hydrogen-air mixtures only. |
Experimental Study on the Methods of Explosion Venting (3rd Report) --Practical Method of Design for Ruputure-Diaphraghm Type Explosion Reliefs--
RR-85-2 |
Toshihiro HAYASHI |
: Explosion venting, or explosion relief, is one of the useful methods of explosion protection, which is applied to various industrial equipments of light structure such as dryers and dust collectors in which flammable gases, vapours or dusts are handled. Even though the effectiveness of its use is generally understood, the present status is far from the practical use in this country by lack of any comprehensive design guide. |
Safety Assessment of Automated Production Systems Using Microelectoronics (2nd Report) --The Comprehensive Logic Models for the Analysis of Accidents Caused by Robots (Part 1)--
RR-85-3 |
Yoshinobu SATO |
: In spite of the fact that some workers were inadvertently killed or injured by industrial robots, we are obliged to use them, because we have yet to overcome such risks and increase productivity. Nevertheless, the robot will be developed and utilized not only for the industrial sectors, but also for our daily life, and in this context the safety of robots will become more important with greater social interest in the near future. |
Critical lgnition Temperatures of Wood Sawdust Layers
RR-85-4 |
Takashi KOTOYORI |
: There exists many research reports on various aspects of pyrolysis and combustion phenomena of wood or woody materials. Instances, however, have been only a few so far where the critical ignition temperatures of bulky stacks of wood sawdusts were measured actually. As for that point, the works by Akita1) or by Gross et al.2), and lately by Anthony et al.3), by John4) and by Schliemann5) are quite precious. |
Safety Assessment of Automated production Systems Using Microelectronics(3rd Report) --Quantification of the Priority-AND-Failure Logic Consisting of Repairable Input Events--
RR-85-5 |
Yoshinobu SATO |
: Any Fault Tree can be expressed as the equivalent of the OR-conjunction of minimal cut-AND-structures. Therefore, if every element of the minimal cuts is quantified, the Fault Tree can also be quantified. |
On the Stress of Bolts of the Slewing Circle of a Truck Crane
RR-85-6 |
Yutaka MAEDA |
: The slewing circle is a rotating mechanism to make a crane slew. Most of slewing circles are made of large-sized ball bearings, and they are installed by several pieces of bolts onto revolving super structures and also onto base carriers. |
Pre-conditional Function of Sensors for Securing Safety
RR-85-7 |
Souichi KUMEKAWA, Noboru SUGIMOTO and Kiyoshi FUKAYA |
: The remarkable progress in reliability of Micro-electronics (ME) in recent years has resulted in sharp increase of the number of microcomputer-controlled machines, but their safety does not follow appropriately. |
Study on the Possibility of Safety Belt's Slipping out of Buckle
RR-85-8 |
Kiyoshi FUKAYA |
: There was an accident that a worker fell down from a ladder with leaving his wearing safety belt on it because the belt slipped out of the buckle. Similar accidents might occur if safety belts do not work well in the case like this. In this context an experimental study was conducted to investigate the cause of the accident. |
Analysis of Accidents in Tunnel Construction Work (4)
RR-85-9 |
Shigeo HANAYASU |
: 1. Introduction |
Analysis on Processes of Labour Accidents --Case Study of the Joetsu-Shinkansen Construction Work--
RR-85-10 |
Yoshimi SUZUKI |
: It is commonly recognized that there are many factors which contribute to the occurrence of labour accidents. |
Durability of Plywood Scaffold Planks and Nethod of Strength Test
RR-85-11 |
Yoshimasa KAWAJIRI |
: Plywood scaffold planks must have sufficient stiffness and strength to sufficiently endure load of workers and materials on them. |
Threshold for Electric Shocks under Water Causing Suffocation of Rabbits --Change of Threshold due tu Conductivity of Water and Body Arrangemsnts--
RR-85-12 |
Eiki YAMANO and Tatsuo MOTOYAMA |
: Working in water such as the sea or a river and the use of electricity in such areas are increasing in recent years. These situations may lead to hazards of underwater electric shock for divers and other workers. This paper reports on an investigation of such hazards. |
Degradation of Rubber Insulating Gloves used in High Voltage Electrical Working
RR-85-13 |
Kenji ICHIKAWA |
: The previous reports1)2) described the results of degradation of electrical and mechanical properties of rubber insulating gloves for use in high voltage electrical working, when they were degraded artificially by the application of voltage stress or ultraviolet radiation. This report presents the insulation performance and mechanical strength of them, after their actual use in high voltage electrical working on site for a certain length of time. Actual tests were conducted on high voltage distribution lines in cooperation with an electrical contractor, because the frequency of use is large and the environment is most severe. |
Considerations of Electrostatic Potential of Charged Insulator Measured by Use of Potentiometer of Induction Type
RR-85-14 |
Yasuyuki TABATA |
: The electrostatic potentiometer of the induction type is often used to assess electrostatic risks caused by the charged material in industry. Although the measurements are carefully carried out, the measured potential, the indicated value of the potentiometer, fluctuates generally whenever the measurements are made. However, the reasons of fluctuations of the potential and the physical meanings obtained from the measurement have hardly been discussed. |