Organisational Factors » LTA hazard analysis/job safety analysis » LTA isolation of plant

4Incorrect Isolation Of Conveyor

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Brief Description of Incident/Accident & Description of Consequences/Outcomes:

At the end of a job on a conveyor it was discovered that the local control isolator had been locked in the "ON" position during the entire job. The persons had incorrectly understood that the isolator handle was in the OFF position and were also able to place a scissor type multiple lock out device through the operating handle locking mechanism. During the course of the isolation other persons had placed locks in the scissor lockout device as part of an isolation procedure. No test for correct isolation of the conveyor was made. No injuries or equipment damage occurred.

Identified Root Causes:

Lack of clear indication for operating handle in the "ON/OFF" position and failure to carry out test of isolation. Also a lack of understanding the isolation procedure existed.

Energy Type(s) Involved:

Entrapment of person in conveyor

Equipment Type(s):

Local Control Isolator, Conveyor Belt

Root & Contributing Cause(s):

LTA competency

LTA design

LTA hazard identification

LTA inspection

LTA isolation

LTA isolation of plant

LTA isolation procedure

LTA testing

LTA work method

Stated or Potential Consequence(s):

Potential Fatality

Preventative/Recommended/Accepted Steps of Risk Mitigation, Points of Interest:

  • Check isolators to determine whether locking in the "ON" position is possible.
  • Ensure isolators and operating handles are clearly marked with "ON/OFF" positions.
  • Ensure persons are adequately trained in the operation of the local control isolators and understand the isolation test process.
  • Clearly identify those isolators that have provision for locking in the "ON" position.
  • Provide a visual means of confirming that the 3 phases of the isolator are open.
  • Ensure there is an adequate "test for off" provision in the isolation procedure.
  • Review isolation procedures.

EMESRT Risk(s):

Energy systems not isolated

Defeat of positive isolation

Isolation switches with lockout

ISOLgate Checklist(s):

Download Energy systems not isolated Checklist.

Download Defeat of positive isolation Checklist.

Download Isolation switches with lockout Checklist.


Queensland Government Department of Employment, Economic Development and Innovation (DEEDI)

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