Set the building reference
Measure roof underside elevation from the finished floor. Use that same floor datum for the starting load-bottom elevation.
BUYING & LAYOUT / TOOL 04
Available Lifting Height Calculator
Use this while checking a proposed workshop arrangement to see how far the bottom of a load can rise after allowing for crane headroom, rigging and the load itself.
Before you start: required inputs
- Use a building section showing the underside of the roof above the finished floor at the lifting line.
- Obtain the required roof clearance and the upper hook position from the proposed crane layout. Measure the rigging depth, load height and starting load-bottom elevation.
Calculation diagram
A PRACTICAL WALKTHROUGH
How to use this calculator
Deduct the complete vertical stack
Allow for roof clearance, the distance from the highest crane component to the upper hook saddle, rigging depth and load height.
Read load travel, not just hook elevation
The main result is how far the load bottom can move upward from its starting elevation. The other outputs show the corresponding upper positions.
Fit a 1.5 m-high load beneath an 8 m roof
THE INPUTS
Roof 8 m; roof clearance 0.3 m; crane headroom 1.2 m; rigging depth 0.5 m; load height 1.5 m; starting load bottom 0 m.
THE RESULT
Available upward load travel is 4.5 m. The upper hook saddle is 6.5 m above floor, the load top reaches 6 m and the load bottom reaches 4.5 m.
What does the result mean?
01
Upper hook elevation locates the hook saddle at its highest permitted position in this geometric arrangement.
02
Maximum load-bottom elevation deducts both the rigging depth and load height from that upper hook position.
03
Available upward travel also deducts the starting load-bottom elevation. A higher starting platform reduces the remaining upward travel.
Watch for this
Using the hoist body height as crane headroom. The required dimension is the full distance from the highest crane component to the hook saddle at its upper limit.
Formula & model conditions +
Upper hook elevation = roof height − roof clearance − crane headroom
Maximum load-bottom elevation = upper hook elevation − rigging height − load height
Available upward travel = maximum load-bottom elevation − starting load-bottom elevation
- All elevations use the finished floor as zero. All vertical dimensions are measured along the same lifting line.
- Hook headroom is measured from the highest crane component to the hook saddle at its upper limit; it is not the hoist body height alone.
- This geometry check does not establish the lower hook limit, runway elevation, structural clearance or suitability of a particular crane.
Common questions
Is the result the hoist’s nominal lifting height?
No. It is the upward travel available to this load within the entered upper geometry. Nominal hoist travel and the lower hook limit must be checked separately.
What if the load starts on a platform?
Use the platform-top elevation as the starting load-bottom elevation if the load rests directly on it. The available upward travel is then measured from that platform.