RIIWHS202E Isolation and Lockout/Tagout Procedures 1 — Questions and Answers
Question 1: What is the primary purpose of isolating energy sources before entering a confined space?
- To reduce noise levels inside the space
- To prevent accidental activation of equipment that could endanger entrants (Correct answer)
- To allow atmospheric testing to be completed faster
- To comply with entry permit paperwork requirements
Correct answer: To prevent accidental activation of equipment that could endanger entrants
Isolation prevents the unexpected release of stored energy or activation of equipment that could cause injury or death to workers inside the confined space.
Question 2: Under Australian WHS regulations, which of the following is the most reliable method of isolating a mechanical hazard in a confined space?
- Placing a 'Do Not Operate' sign on the control panel
- Notifying the supervisor verbally that the equipment is off
- Physical disconnection or blanking of the energy source with lockout applied (Correct answer)
- Switching off the equipment at the local isolator only
Correct answer: Physical disconnection or blanking of the energy source with lockout applied
Physical disconnection or blanking combined with lockout provides positive isolation that cannot be overridden accidentally, unlike signs or verbal notification alone.
Question 3: What does the term 'positive isolation' mean in the context of confined space entry?
- Confirming that all workers are in a positive frame of mind before entry
- Physically separating the energy source so it cannot be reconnected without deliberate action (Correct answer)
- Using a positive pressure air supply inside the space
- Testing the atmosphere and getting a positive result
Correct answer: Physically separating the energy source so it cannot be reconnected without deliberate action
Positive isolation means the energy source is physically separated — for example by a blank flange or physical disconnection — so it cannot be restored without removing the isolation device.
Question 4: When multiple workers are entering a confined space under a single isolation, each worker should:
- Share one lock between them to avoid crowding the lockout point
- Trust that the supervisor's lock provides adequate protection for everyone
- Apply their own personal lock to the lockout device (Correct answer)
- Wait outside until the lead worker has verified isolation is complete
Correct answer: Apply their own personal lock to the lockout device
Each individual worker must apply their own personal lock so that the energy source cannot be re-energised while any worker remains in the space.
Question 5: A 'blanking plate' or 'blind flange' is used in confined space isolation primarily to:
- Block the entry point to prevent unauthorised access
- Physically seal a pipe or duct to prevent the flow of substances into the space (Correct answer)
- Support structural elements inside the confined space
- Hold atmospheric monitoring equipment in position
Correct answer: Physically seal a pipe or duct to prevent the flow of substances into the space
A blank flange or blanking plate is inserted into a pipe or duct to provide a physical barrier preventing gases, liquids or other substances from entering the confined space.
Question 6: Before removing an isolation lock at the end of confined space work, the responsible person must first:
- Inform the next shift supervisor of the work completed
- Confirm all workers have exited and are accounted for (Correct answer)
- Complete the post-entry cleaning requirements
- Request approval from the site safety officer
Correct answer: Confirm all workers have exited and are accounted for
All workers must be confirmed as out of the space before any isolation is removed, ensuring no person remains at risk when energy is restored.
Question 7: Which Australian Standard provides guidance on the isolation of plant and equipment in the context of hazardous energy control?
- AS 1940 – Storage and Handling of Flammable Liquids
- AS/NZS 4024.1604 – Safety of Machinery: Design of Controls for Isolation of Energy (Correct answer)
- AS 1668 – The Use of Ventilation and Airconditioning in Buildings
- AS 4332 – The Storage and Handling of Gases in Cylinders
Correct answer: AS/NZS 4024.1604 – Safety of Machinery: Design of Controls for Isolation of Energy
AS/NZS 4024.1604 covers the design of control measures for the isolation and dissipation of hazardous energy in machinery and plant.
RIIWHS202E Isolation and Lockout/Tagout Procedures 1
What is the primary purpose of isolating energy sources before entering a confined space?