IPAF Safe Working Load & Stability — Questions and Answers
Question 1: What is the Safe Working Load (SWL) of a MEWP?
- The maximum total weight (persons, tools, and materials) that the platform is rated to carry safely (Correct answer)
- The maximum weight of a single person on the platform
- The maximum height the MEWP can reach
- The maximum wind speed at which the MEWP can operate
Correct answer: The maximum total weight (persons, tools, and materials) that the platform is rated to carry safely
The SWL is the maximum combined weight of everything on the platform — persons, tools, equipment, and materials. Exceeding the SWL risks overloading the machine, causing structural failure or overturning.
Question 2: A MEWP has a platform SWL of 230 kg. Two workers each weigh 90 kg. They wish to take 80 kg of materials onto the platform. Is this within the SWL?
- No — the total is 260 kg, which exceeds the 230 kg SWL (Correct answer)
- Yes — the total is 230 kg exactly, which is acceptable
- Yes — materials are not counted toward the SWL
- No — only one person is allowed on a MEWP at any time
Correct answer: No — the total is 260 kg, which exceeds the 230 kg SWL
90 kg + 90 kg + 80 kg = 260 kg, which exceeds the 230 kg SWL. This lift cannot proceed as it stands. Materials must be reduced or one person must remain on the ground.
Question 3: How does wind speed affect MEWP stability and safe operation?
- Wind creates lateral forces on the platform and operator that increase overturning risk — operation must stop when wind exceeds the manufacturer's limit (Correct answer)
- Wind only affects tall boom lifts, not scissor lifts
- Wind speed only matters if the MEWP is near a building
- Only gusts above 60 mph are a concern
Correct answer: Wind creates lateral forces on the platform and operator that increase overturning risk — operation must stop when wind exceeds the manufacturer's limit
Wind exerts lateral force on the platform, operator, and any materials being carried. This force creates an overturning moment that increases with height. Operation must stop when wind exceeds the manufacturer's specified limit.
Question 4: Why does the SWL of a boom lift decrease as the boom is extended to greater radii?
- Greater outreach increases the overturning moment — the machine's stability limits what it can safely lift at each radius (Correct answer)
- SWL increases with outreach because the machine is more stable when extended
- SWL is constant regardless of boom position
- Outreach only affects lift speed, not capacity
Correct answer: Greater outreach increases the overturning moment — the machine's stability limits what it can safely lift at each radius
As the boom extends outward, the overturning moment (load multiplied by outreach distance) increases. At greater radii, the machine approaches its stability limit at lower loads, so the SWL decreases.
Question 5: What is the significance of the manufacturer's load chart for a MEWP?
- It shows the maximum safe load at different heights and outreach positions, enabling operators to verify the planned operation is within safe limits (Correct answer)
- Load charts are only required for cranes, not MEWPs
- It shows fuel consumption at different heights
- Load charts are advisory only
Correct answer: It shows the maximum safe load at different heights and outreach positions, enabling operators to verify the planned operation is within safe limits
The load chart shows the SWL at different working positions (height and outreach combinations). Before operation, the planned task must be verified against the load chart to confirm it is within safe limits.
Question 6: What does the MEWP's 'maximum platform height' mean?
- The highest point to which the platform floor can be raised — not the maximum safe working height for all conditions (Correct answer)
- The maximum height at which full SWL can be utilised
- The maximum height in all wind conditions
- The height of the platform cage sides
Correct answer: The highest point to which the platform floor can be raised — not the maximum safe working height for all conditions
Maximum platform height is the highest point the platform floor can reach. However, at maximum height, stability is most critical — the SWL and wind limits may be more restrictive than at lower heights.
IPAF Safe Working Load & Stability
What is the Safe Working Load (SWL) of a MEWP?