1. The copyright to this material belongs to the Korea Occupational Safety and Health Agency. Unauthorized use and distribution are prohibited. If an individual uses this for non-commercial purposes, the Korea Occupational Safety and Health Agency must be cited as the source. A corporation using this material must obtain permission from the Korea Occupational Safety and Health Agency first. Using this material without prior permission will be considered copyright infringement, and legal action may be taken. Manufacture Fall of a heavy object while operating a mobile crane ( Crane - fall ) 2009.05 -Serious Accidents in Manufacturing - 안전분야 - 교육자료 미디어개발 2009-77-455

2. Table of Contents I. Fatality Overview II. Process Overview III. Fatality Object IV. Fatality Process V. Fatality Cause VI. Precautions

3. I. Fatality Overview II. Process Overview III. Fatality Object IV. Fatality Process V. Fatality Cause VI. Precautions I.Fatality Overview Place: crane operating site in Choongbuk Victim: mobile crane operator While the victim was lifting a barge in the riverside with a mobile crane (225 ton) A temporarily welded structure (lug) that was hanging at crane lifting shackle was fractured causing falling of the barge upon the crane operator seat. The victim who was operating the crane in the operator seat was crushed to death. Fatality Site and Illustration expected position of the barge barge

4. II.Process Overview Process Overview (barge lifting operation ) Process –The victim asked worker A to mount lugs to hang hooks on two locations on the barge to turn a barge over. –Worker A told the rough shape of lug heard from the victim to worker B, work A ’ s acquaintance, and asked him to mount lugs on the barge. –Worker B got materials in that morning and made lugs to mount them on each sides of barge by welding Positioning HangingLifting Safe Arrival Dismantlement Arrival Surrounding Analysis I. Fatality Overview II. Process Overview III. Fatality Object IV. Fatality Process V. Fatality Cause VI. Precautions Fatality Process

5. III. Fatality Object Fatality Object: mobile crane –Lifting load: maximum 225 ton (at working radius 8.5m) –Boom length: 15.1m ~ 60m (5 sections) the boom was extended at about 2.5nd sections at the time of fatal accident (approx. 27M) –Maximum elevating height: 60m I. Fatality Overview II. Process Overview III. Fatality Object IV. Fatality Process V. Fatality Cause VI. Precautions Fatality crane

6. III. Fatality Object Fatality Object: barge –Dimension: length – approx. 16m, width - 9m, height - 1.1m –Type: non-driving and box-type steel plate structure (steel plate thickness of barge body: 5mm) –Weight: N/A Supposing that the out part of the barge body was made of 5mm steel plate; –Size of outer steel plate = [16m x 9m + (16m + 9m) x 1.1m] x 2 = 343 ㎡ –Weight of outer steel plate = 343 ㎡ x 0.005m x 7.8 ton/ ㎥ = 13.38 ton I. Fatality Overview II. Process Overview III. Fatality Object IV. Fatality Process V. Fatality Cause VI. Precautions Lug Barge

7. IV. Fatality Process The victim entered working position driving 225- ton mobile crane at about 13:00. The victim and co-worker A completed preparations such as outriggers positioning for the mobile crane operation by 14:00. The co-worker A hung two assisting wire ropes at mobile crane hook and connect each assisting wire rope to two lugs mounted on the barge using shackles. To turn the barge over, they mounted lugs on the side of barge the opposite side of the crane operator seat. I. Fatality Overview II. Process Overview III. Fatality Object IV. Fatality Process V. Fatality Cause VI. Precautions

8. IV. Fatality Process After the connection, the victim started to lift up slowly the barge that was connected to the mobile crane. At about 14:40, when the victim erected the barge completely up and tried to lift the barge up, lug (A) on the right side (from the view from the operator seat) was fractured with a roaring sound causing detaching of the shackle off the barge. After this, barge was leant owing to partiality load and the lug (B) on the left side was fractured off the welding area of the plate. The two shackles hanging the barge were completely separated. The free barge from shackles fell upon the crane and killed the victim on the spot. I. Fatality Overview II. Process Overview III. Fatality Object IV. Fatality Process V. Fatality Cause VI. Precautions

9. V. Fatality Cause Unprepared work plan –To handle a barge, a heavy object, using a mobile crane, you must check for the details of heavy object ’ s type and shape, operation process and order, workplace size and topography in advance and notify the workers of the details. However, these rules were not observed. –Lug condition on which heavy load is applied must be checked prior to any work. However, this rule was not observed either. Inferior lug welding - Lugs were welded to support the barge of dozens of tons. However, welding with enough strength to hold the barge was not performed at the site and caused fracture of the welding area and falling of the barge. I. Fatality Overview II. Process Overview III. Fatality Object IV. Fatality Process V. Fatality Cause VI. Precautions

10. Preparation of work plan and observance –To handle any heavy object, you must check for the details of heavy object ’ s type and shape, operation process and order, workplace size and topography in advance and notify the workers of the details. –To prevent any accident, protective measures (lug welding method, etc) against potential hazards must be taken. –Prior to any site operation, you must check for observance of the above-mentioned details. I. Fatality Overview II. Process Overview III. Fatality Object IV. Fatality Process V. Fatality Cause VI. Precautions

11. Improving lug welding method –To weld lugs on a barge body, you must conduct leveling inequalities to prevent foreign material such as rust on the welding area of both lug and barge body in advance. In addition, plane processing is necessary on welding area on lug for good adhesion with welding material and lug welding must be done in a way to enlarge welding cross section. –Gas arc welding is recommended in a site. When AC arc welding is necessary, a well skilled worker should lower the welding speed to secure enough strength for the relevant work. I. Fatality Overview II. Process Overview III. Fatality Object IV. Fatality Process V. Fatality Cause VI. Precautions

12. Thank You.