| Case Name |
Fire of hydraulic oil caused due to damage to a drain hose during a performance test of a hydraulic motor |
| Pictograph |
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| Date |
December 7, 1992 |
| Place |
Tabuse, Yamaguchi, Japan |
| Location |
Machine shop |
| Overview |
On December 7th, 1992. A fire occurred during a performance test for a hydraulic motor at a machine shop. Parts of the motor broke down during the test, and an internal pressure of 10.0 MPaG was added to a drain hose. The drain hose was damaged. Its maximum operating pressure was 1.0M PaG and minimum breaking pressure was 4.0 MPaG. The hydraulic oil inside leaked out, and it caught fire.
Countermeasures should be prepared for a trouble that causes an over-pressure. |
| Incident |
A fire occurred during a test at a pump factory. Some parts inside a hydraulic motor were damaged during a performance test for the motor, and about 10 MPaG oil pressure was added to the drain hose. The drain hose was damaged, hydraulic oil spouted out, and a fire broke out. The fire burned the following: an oil pressure generator set in a steel-frame concrete block one-story building with 140 square meters of the floor space. Three people were seriously injured and one person was slightly injured. Refer to Fig2. |
| Processing |
Consumption and usage |
| Substance |
Hydraulic oil |
| Type of Accident |
Leakage, fire |
| Sequence |
On December 7th, 1992. A performance test was carried out at 1600 rpm and at a pressure of 20 MPaG during the morning. In the afternoon the test was restarted.
13:15. The drain hose was damaged at a pressure of 10 MPaG as the pressure was gradually raised. The hydraulic oil spouted and ignited. An oil-pressure generator set in the steel-frame concrete block one-story building with the floor space 140 square meters was destroyed by the fire. Three persons were seriously injured and one person was slightly injured.
14:00. The fire was confirmed to have been extinguished. |
| Cause |
Trouble with the machine was the main cause. The ignition cause is not clear.
During a performance test for an oil pressure motor, some parts in the motor were damaged, and about 10 MPaG of pressured oil was added to a drain line with a design pressure of 0.2 MPaG. The oil-proof rubber hose with a working pressure of 1.0 MPaG and a minimum breaking pressure of 4.0 MPaG was damaged, and hydraulic oil spouted out. Spouted out hydraulic oil became a mist, was ignited with some fire sources, burned explosively, and the fire spread. |
| Countermeasures |
1. The emergency shutdown facilities are changed to meet more various problems.
2. Preventive regulations are restudied, and recognition of fire prevention by workers should be deepened.
In this accident, if the tester could predict the troubles in inside parts would cause excessive pressure onto a drain hose, he could take countermeasures against the pressure and could prevent the accident. The most important countermeasure is to reach the higher technical level and to prepare sufficient countermeasure. |
| Knowledge Comment |
In the test plan, sufficient consideration of accidents is necessary. It is important that prior and sufficient safety countermeasures are prepared for a test. |
| Background |
An inadequate design or inadequate performance test plan might be the true cause of the accident. In a performance test, an accident must be prevented even if various problems arise in the machine. In the morning, a test at 20 MPaG caused no problem, so the tester might feel safe at a 10 MPaG test.
Why was the drain valve pressured? If the drain valve was closed, the leakage would not have occurred (due to insufficient data, judgment was impossible.) |
| Reason for Adding to DB |
Example of fire caused due to damage to the inside part of a hydraulic motor |
| Scenario |
| Primary Scenario
|
Poor Value Perception, Poor Safety Awareness, Inadequate Risk Recognition, Organizational Problems, Poor Management, Slackness of Management/Habit, Carelessness, Insufficient Precaution, Mannerism, Planning and Design, Poor Planning, Poor Inspection Planning, Bad Event, Mechanical Event, Fault, Regular Operation, Erroneous Operation, Not Closing Valve, Failure, Fracture/Damage, Secondary Damage, External Damage, Leakage/Fire, Bodily Harm, Injury, 4 person injured, Loss to Organization, Economic Loss, Direct Monetary Damage 63 million yen
|
|
| Sources |
Fire and Disaster Management Agency. Major cases of accidents. Fire during performance test of hydraulic motor. Accident cases of dangerous materials. pp.33, 416-417.
|
| Number of Injuries |
4 |
| Physical Damage |
A diesel engine, an oil pressure generator set including a hydraulic pump, a hydraulic motor for the test and a hydraulic motor for the load were damaged by a fire. 1200 L of fuel oil and 2500 L of hydraulic oil flowed out and burned. |
| Financial Cost |
¥ 63 million (Accident cases of dangerous materials). |
| Multimedia Files |
Fig2.Equipment schematic diagram
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| Field |
Chemicals and Plants
|
| Author |
DOBASHI, Ritsu (School of Engineering, The University of Tokyo)
TAMURA, Masamitsu (Center for Risk Management and Safety Sciences, Yokohama National University)
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