Platform Load, Wind, and a Charged Waterway
You are the operator of an 85-ft rear-mount elevating platform at a four-story office building. A worker with a suspected femur fracture is on the roof 62 ft up, packaged in a stokes basket with blankets and straps; basket and patient weigh 250 lb. Two firefighters in full PPE, 240 lb each with equipment, are on the roof to help load. The platform placard reads 750 lb capacity, reduced to 500 lb when the waterway is flowing. The manufacturer limits operation to 25 mph wind. The platform anemometer reads 17 mph steady with gusts to 29 mph, and the platform buffets as it swings past the building corner. The IC also wants the platform monitor charged to knock down a small fire in rooftop HVAC equipment before it reaches a gas line. A second aerial is 12 minutes out.
1. Can you lift both firefighters and the basket in one trip? Show the load reasoning and the configuration you would use.
Read the worked answer
Dry, the arithmetic is 250 + 240 + 240 = 730 lb against a 750-lb placard. That looks legal but leaves 20 lb of margin and ignores anything the crew carries aboard: a set of irons or a saw is easily 40 lb, which puts you at 770 lb and over the placard. Margin that thin is not a margin.
Charged, the limit drops to 500 lb and the two-firefighter plan is gone entirely. The usable configurations are:
- Waterway dry: basket, patient, and one firefighter at 490 lb, with the second firefighter reaching the ground by interior stairs or ground ladder.
- Waterway charged: send the platform up empty of firefighters and use it as a master stream after the victim is down, not during the lift.
The exam point is that the placard reduction for waterway flow is a capacity change, not a caution, and the operator recalculates the lift rather than assuming the dry number carries over.
2. The wind is 17 mph steady with gusts to 29 mph. How does that affect your decision?
Read the worked answer
The steady reading is inside the 25-mph limit; the gust is not. Manufacturer wind limits are written to cover the worst instantaneous condition the device sees, and a gust loads the boom and the platform as a dynamic input. Two other factors push the same direction: wind speed rises with height, so a 17-mph ground reading can be higher at 62 ft, and the buffeting at the corner is mechanical turbulence, which is harder on the structure than smooth flow of the same velocity.
Reasonable courses of action, in order: re-measure at the platform at working height rather than trusting the ground reading; reposition to the windward face where the airflow is cleaner and the platform is out of the corner eddy; hold and re-check until gusts are consistently below the limit; and keep the second aerial request active as the alternate access plan. If buffeting increases or the gust spread widens, bring the platform down and let the roof crew use the interior stairwell. Record the readings and times; that record is what supports your decision afterward.
3. The IC insists you charge the waterway while the crew is on the platform. What is your response, and what do you offer instead?
Read the worked answer
The answer is no, and the reason is arithmetic, not attitude. With the waterway charged the platform capacity drops from 750 to 500 lb, which will not hold the basket and a firefighter, and the nozzle reaction from a monitor stream adds a dynamic load at the worst possible moment, when people are at the tip and the platform is already buffeting.
What you offer instead:
- Complete the lift with the waterway dry, get the patient down, then charge and flow with the platform empty and clear.
- Put a handline in service from the building standpipe or a ground position to protect the HVAC area while the lift proceeds.
- Ask the second aerial, when it arrives, to take the fire attack from a separate position so the rescue platform is not doing both jobs.
Then tell the IC plainly: the platform is available for rescue now or for fire attack after the rescue, not both at once, and the placard is the reason. That gives the IC a workable alternative rather than a refusal, which is what the exam wants to see.