1. Death by the Strike of a Bolt Escaping from Hydraulic Cylinder during Hydraulic Test Grave Accident Case in Manufacturing Sector 2010- 교육미디어 -1016

2. The copyright of this material is owned by the Korea Occupational Safety and Health Agency (KOSHA) and unauthorized and arbitrary use hereof is strictly prohibited. However, if an individual wishes to use it for a non-commercial objective, he/she may use do so by revealing its source. If a corporation wishes to use it, permission must first be obtained from KOSHA. Any unauthorized use hereof constitutes a breach of copyright law and such action is subject to legal sanctions. Detail II Cause III Prevention IV Overview I I Death by the Strike of a Bolt Escaping from Hydraulic Cylinder during Hydraulic Test

3. Overview of Accident When: May 10, 2008, 14:30 Where: Hydraulic test ground, XX Industrial Company located in Saha-gu, Busan What: The victim filled the hydraulic cylinder and increased the pressure to conduct a hydraulic test on the hydraulic cylinder, which was part of a steering engine. How: The cylinder was found leaking at a bolt and the victim fastened the bolt in front of it. Why: The bolt escaped and struck the victim in the abdomen. Ⅰ Ⅰ

4. Death by the Strike of a Bolt Escaping from Hydraulic Cylinder during Hydraulic Test Leak check Details of Accident Hydraulic test process Ⅱ Ⅱ Cylinder filled with water Pressuriza tion Cylinder received Flange and bolt fastened Carriage Accident

5. Death by the Strike of a Bolt Escaping from Hydraulic Cylinder during Hydraulic Test Details of Accident On May 10, 2008, at 08:30, the victim attached a flange to hydraulic cylinders (4 units), which were parts of a steering engine of a vessel and fastened a bolt to block the hole on a cylinder. The system was filled with water to start a hydraulic test. After lunch at 13:30, the victim began pressurizing the hydraulic cylinder with a tester. At 14:00, the internal pressure of the cylinder reached 412.5kgf/ ㎟, which was the test pressure and the victim checked if it was leaking. A leak was found at the bolt and the victim fastened the bolt (assumed) when the bolt escaped and struck the victim in the abdomen, causing death. Ⅱ Ⅱ

6. Death by the Strike of a Bolt Escaping from Hydraulic Cylinder during Hydraulic Test Details of Accident Ⅱ Ⅱ Bolt: M24 x P2 Hydraulic cylinder

7. Death by the Strike of a Bolt Escaping from Hydraulic Cylinder during Hydraulic Test Details of Accident Ⅱ Ⅱ Workshop of accident Initial operation position Position where the victim was found lying

8. Death by the Strike of a Bolt Escaping from Hydraulic Cylinder during Hydraulic Test Details of Accident Ⅱ Ⅱ Hydraulic cylinder

9. Death by the Strike of a Bolt Escaping from Hydraulic Cylinder during Hydraulic Test Details of Accident Ⅱ Ⅱ Drain hole of the hydraulic cylinder and bolt for the hole The thread of the bolt was found to be damaged after the accident at the hydraulic cylinder

10. Death by the Strike of a Bolt Escaping from Hydraulic Cylinder during Hydraulic Test Details of Accident Ⅱ Ⅱ Reuse of bolts used for hydraulic tests

11. Death by the Strike of a Bolt Escaping from Hydraulic Cylinder during Hydraulic Test Lack of bolt and washer reuse standard The torques of the reused bolts and washers were reduced due to wear and tear because there was no clear standard for reuse. Operation dependent on rule of thumb The bolt should have been fastened to an appropriate torque, but it was fastened based on the operator’s rule of thumb and the torque that the material could withstand was exceeded, damaging the thread. Failure to observe the hydraulic test principles If a leak is found during a hydraulic test, the cylinder should be properly bled before working on the leak. However, the operator attempted to resolve the leak problem without bleeding the cylinder. Failure to prevent the bolt from loosening Ⅲ Ⅲ Cause of Accident

12. Death by the Strike of a Bolt Escaping from Hydraulic Cylinder during Hydraulic Test Prevention of Accident A clear standard for bolt reuse should be established and managed. A torque wrench should be used to fasten a bolt and a fastening angle should be specified to allow the bolt to be fastened to a proper torque. A hydraulic test procedure should be established and followed. Measures should be taken to prevent the bolt from loosening A key or pin-type mechanical fastening device or adhesive should be used to properly fasten the bolt and prevent it from loosening. Ⅳ Ⅳ

13. Death by the Strike of a Bolt Escaping from Hydraulic Cylinder during Hydraulic Test