POM L4

Which of the following does not cause a plant to shutdown?

• Cleaning a blocked filter but there is a spare filter

• Maintenance

• System interlock

• Emergency shutdown

_____ isolation must mean that equipment is isolated in such a way that there is no possible chance of recontamination. (Pick the best answer)

• Negative

• Positive

• Electrical

• Double block and bleed

Which of the following best describe double block and bleed?

• 
• 
• 
• 

Which of the following is not safe condition method?

• pressurizing

• depressurizing

• isolation

• blinding

_____ is used to remove any flammable/toxic gases inside the pipeline and vessel.

• Ventilation

• Draining

• Purging

• Blanketing

Which of the following is not maintenance purpose?

• Inspection

• Upgrade system integrity & reliability

• Replace damage/faulty equipment

• Replacing a healthy pipeline

Answer explanation

Healthy pipelines do not need any replacement if there is no reason to (e.g. leak, corrosion, etc.) as it will only increase the cost. They can still be used.

Which of the following is not a type of isolation?

• Double block and bleed

• Depressurzing

• Positive isolation

• Electrical isolation

There is a high risk of leakage when a single valve is used to isolate a pipeline

• TRUE

• FALSE

Answer explanation

Single valve does not provide a completely sealed barrier as it will inevitably leak. Only by inserting a metal plate between the flanges can guarantee a disconnection.

Which requirement is explicitly stated regarding protection of persons working on plant?

• All workers may share one Personal Danger tag

• Each person shall be protected by their Personal Danger tag and lock

• Only authorised workers require Personal Danger tags

• Personal Danger tags are optional if supervision is present

According to the procedure, when should personal isolation activities be carried out?

• After maintenance is completed

• During equipment operation

• Only during emergency repairs

• Before work begins