Abstract of Special Research Report (RR-17)
National Institute of Occupational Safety and Health, Japan
Elimination of Static Electricity by Use of Radioisotopes --Electric Poential Decay of Charged Body--
RR-17-1 |
Yasuyuki TABATA, Katsuhiro SAKANUSHI and Tsutomu KODAMA |
: Static electricity charged on the insulating materials leads to spark ignition in the explosive gas or the vapour atmosphere. It can often cause serious accidents in the various industries and consequently several counterplans are considered in order to eliminate static electricity. |
Study of the Safe Gaps with Naphtha Cracked Gas/Air Mixtures for Flanged Joints
RR-17-2 |
Heizaburo TSURUMI and Toei MATSUDA |
: Experimental safe gaps with 1 inch flanges for naphtha cracked gas/air mixtures under atmospheric pressure have been determined in the standard spherical vessel. |
Joint of Strut in Excavation Work
RR-17-3 | ||||||||||||||||||||||||||||||||||||
Yoshitada MORI and Ikuo MAE | ||||||||||||||||||||||||||||||||||||
: The constitution of joint in the member of temporary structure is simplified by comparison with that of permanent structure, therefore, such a joint is prone to have some structural defects. If the incomplete joint is used in the principal member such as a strut in excavation work, the buckling strength of strut is reduced, and the reduction of strength may bring about the failure of the structure.
On the basis of the results from the theoretical analysis and the experimental data, the buckling strength of struts having the various types of joints are calculated, and the rate of decrease in buckling strength are estimated as follows.
In conclusion, (a) type joint needs no anticipation of the decrease of buckling strength in practical uses, (b) type joint should be dealt with consideration of the decrease of buckling strength, and (c) type joint should be set near the restraint point such as the intersecting point of structural members. |
The Quenching Ability of Flame Arresters for n-Hexane
RR-17-4 |
Kougaku KOMAMIYA |
: For the prevention of unwanted fires and gas explosion disasters in chemical industries, flame arresters are used mounting on oil tanks or other similar installations. However, their effectiveness has not been well established in experiments. |
Fundamental Study of Testing Appratus for Determining Minimum Igniting Current for Explosive Gas Atmospheres
RR-17-5 |
Ryuji TANAKA |
: In designing intrinsically safe electrical apparatus and circuits, the incendivity of the spark discharges under the atmospheric pressure is a vital problem. Many reports have so far been published on the incendivity of electrical sparks for methane-air mixtures, while a few for many other inflammable gases or vapours. |
The Minimum Igniting Currents for Explosive Gas- or Vapour-Air Mixtures by Break-Spark in Low-Voltage d.c. Inductive Circuits
RR-17-6 |
Ryuji TANAKA |
: The author previously made clear the ignition sensitivity of the IEC type apparatus for testing intrinsically safe electrical apparatus and circuits for use in explosive gas atmospheres and that the ICE type could appropriately simulate break-sparks of low voltage inductive circuits and resistive circuits with a supply voltage of not less than some 20 volts as regards the spark ignition. |
Basic Study of Intrinsically Safe Circuits for Methane-Air Mixtures under Hyperbaric Pressure
RR-17-7 |
Ryuji TANAKA |
: The minimum ignition limits in low-voltage inductive, resistive and capacitive circuits are determined under hyperbaric methane-air mixtures using the IEC-type spark-producing apparatus. |