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Oil tank sight glass push buttons wired open

What happened

On a visit to an engine room, a serious bypassing of safety controls was observed. Both top and bottom level check push buttons on an Oil Tank Sight Glass were inhibited by wire. The sight glass is used to check the oil level in storage tanks. It is designed such that a button has to be pushed to check and verify the level of the oil tank.  The button allows a connection between the sight glass and the oil tank. Whilst the button was wired open, if the glass tube were to be accidentally broken or damaged, then the contents of the tank could easily spill into the engine room with consequent further serious hazard of slips/trips, fire, and lack of oil where it was intended.

Top of sight closing device blocked by wire
Bottom of sight closing device blocked by wire

What was the cause?

  • Unsafe behaviour – this was an intentional override of a design feature related to safety-critical equipment
    • The oil level gauge closing device had been inhibited with wire and remained in open position for a long time.

Members may wish to refer to

Safety Event

Published: 13 December 2022
Download: IMCA SF 28/22

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