Load Moment Check — Roof Derrick
Working load moment vs the roof derrick rating — the number the whole chart hangs on.
Dismantling derricks lift the tower crane that built the tower — small machines doing short-radius, high-consequence picks on a finished roof. Their moment is modest by design: the building's roof slab, not the derrick, is usually the limiting structure. Check both numbers.
Formula
Note: Rigging and crane decisions are life-safety critical. This calculator is a planning aid — the load chart, sling tags, site lift plan and a qualified lift director govern every real lift.
Working load moment vs the roof derrick rating — the number the whole chart hangs on. A free crane load, wind & rigging safety tool — no sign-up, no upload, instant results in your browser.
About Load Moment Check — Roof Derrick
Load Moment Check — Roof Derrick computes the governing relationship M = W × r vs rated t·m live as you type. Dismantling derricks lift the tower crane that built the tower — small machines doing short-radius, high-consequence picks on a finished roof. Their moment is modest by design: the building's roof slab, not the derrick, is usually the limiting structure. Check both numbers. Defaults are pre-filled with realistic values for this exact scenario, and the worked example substitutes your numbers step by step so the math is never a black box.
How to use Load Moment Check — Roof Derrick
- 1Enter your values — Gross load, Working radius, Rated load moment (sensible defaults are pre-filled).
- 2Read the live results: Working moment, Moment utilization.
- 3Check the "with your numbers" line to see M = W × r vs rated t·m substituted step by step.
- 4Adjust inputs until the scenario matches yours, then copy or share the result.
Why use Load Moment Check — Roof Derrick?
- ✓Instant, free and private — every calculation runs client-side in your browser; nothing is uploaded
- ✓Built on the stated formula M = W × r vs rated t·m with authoritative sources cited on the page (EN 13001 / EN 14439 — Crane design & tower crane standards; ASME B30.5/B30.9/B30.20 — Cranes, slings and below-the-hook devices)
- ✓Dismantling derricks lift the tower crane that built the tower — small machines doing short-radius, high-consequence picks on a finished roof.
- ✓SI ⇄ Imperial toggle converts your inputs in place, so you can work in the units your drawings use
Frequently asked questions
What formula does the load moment check — roof derrick use?+
It evaluates M = W × r vs rated t·m, exactly as published. Sources: EN 13001 / EN 14439 — Crane design & tower crane standards; ASME B30.5/B30.9/B30.20 — Cranes, slings and below-the-hook devices. The substituted worked example on the page lets you verify every step against the textbook.
How should I read the result — and how far can I trust it?+
Dismantling derricks lift the tower crane that built the tower — small machines doing short-radius, high-consequence picks on a finished roof. Rigging and crane decisions are life-safety critical. This calculator is a planning aid — the load chart, sling tags, site lift plan and a qualified lift director govern every real lift.
When is this calculator the right tool for the job?+
Working load moment vs the roof derrick rating. Their moment is modest by design: the building's roof slab, not the derrick, is usually the limiting structure. For neighbouring scenarios, the related tools below cover the same engine with different presets.
Does it support both metric and imperial units?+
Yes — the SI ⇄ Imperial toggle converts the values already in the fields, preserving the physical quantity, so you can flip mid-calculation without re-entering anything.
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