Tree-rigging force prompts can help a crew ask better questions before a job review, but they cannot accept a rope, hardware item, anchor, tree, lowering method, or work zone. A local shock-load screen only knows the values typed into it: estimated piece weight, fall distance, rope length, rope row, diameter row, and configuration row.
This guide documents the source boundaries around the ToolGrit rigging shock-load screen. It points users toward ANSI Z133, TCIA training context, manufacturer rope instructions, ASME B30, OSHA, Crosby, USDA Forest Products Laboratory, and NIST source checks without turning those sources into a field procedure or product acceptance.
What the App Screens
The app uses a local energy-balance prompt to turn entered piece weight, fall distance, rope length, rope-family elongation, and configuration row into peak-force, static-multiple, drop-factor, block-load, and local margin prompts. It is useful for comparing assumptions, not for accepting a rigging setup.
The drop-factor prompt is fall distance divided by rope length in the local model. The force result changes quickly when the entered fall distance, rope length, or rope-row elongation changes. Those inputs need independent verification before they influence a work decision.
The app does not model tree movement, hinge behavior, branch union strength, natural crotch friction, rope-on-bark friction, lowering-device slip curve, worker control, knots, splices, bend radius, side loading, hardware damage, weather, traffic, or public exposure.
Dynamic Rigging Shock Load Calculator
Calculate peak impact force on arborist rigging from free-fall distance, rope elongation, and rigging configuration.
Rope, Hardware, and Anchor Source Gaps
Rope-family rows are local prompts only. Current manufacturer instructions, product tags, model-specific tensile data, elongation basis, WLL/tag data, knots, splices, bend radius, wet or frozen condition, contamination, heat glazing, abrasion, age, and retirement status remain outside the app.
Rigging blocks, slings, shackles, connectors, friction devices, and cranes need their own source checks. ASME B30 and OSHA source pointers help identify the topics, but exact hitch, sling angle, D/d, side loading, tag data, inspection, removal criteria, load chart, setup, operator, and employer procedure are separate work.
Tree anchors and natural crotches are not solved by a formula in this app. Species, decay, included bark, union geometry, load direction, prior defects, cavities, root condition, weather, and visible and hidden damage need qualified arborist review.
Site Procedure and Qualified Review
A force estimate belongs inside a broader job review. The qualified team still needs verified piece weight, selected equipment, rigging point, work sequence, communication, exclusion zone, traffic and public protection, weather, electrical hazards, rescue planning, and employer procedure.
ANSI Z133, TCIA, OSHA, ASME, manufacturer instructions, and company procedures are not interchangeable. Each source points to a different boundary: arboricultural practice, training, employer obligations, sling and hardware topics, product limitations, and local policy.
The report export is best used as a checklist of unresolved assumptions. It is not proof that the crew, equipment, tree, site, or procedure is ready.