Oil tank sight glass push buttons wired open

  • Safety Flash
  • Published on 13 December 2022
  • Generated on 21 August 2026
  • IMCA SF 28/22
  • 1 minute read

On a visit to an engine room, a serious bypassing of safety controls was observed.

What happened?

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

Top of sight closing device blocked by wire

Bottom 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.

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