Crane Net Capacity After Deductions
Net capacity for the hook after the OSHA 1926.1417(o) deduction stack (hook block, jib, wire rope), the total hook load.
Example
You enter
- Gross chart capacity at radius (lb) 30000
- Hook block / overhaul ball (lb) 800
- Wire-rope deduction (lb) 400
- Below-the-hook gear (lb) 600
- Load weight (lb) 22000
You get
- Net capacity for the hook 28800 lb
- Total hook load 22600 lb
- Percent of net 78.5%
Details, formula, and sources
The percent of net, and the 75 / 90 / 100 percent flags. The manufacturer's load chart governs.
net = gross_chart - hook_block - jib - wire_rope; total_hook = load + below_hook; pct_of_net = total_hook / net x 100; flags at 75 / 90 / 100%.
OSHA 29 CFR 1926.1417(o) deduction stack and ASME B30.5 (Mobile and Locomotive Cranes) by name; arithmetic on chart numbers.
OSHA 1926 Subpart CC is free at osha.gov. The capacity numbers come from the manufacturer's load chart.
Estimate. Head rigger and manufacturer working-load-limit charts govern. Inspect every piece of hardware before the show.
Field names used by the API: gross_chart_lb, hook_block_lb, wire_rope_lb, below_hook_lb, load_weight_lb, net_capacity_lb, total_hook_lb, pct_of_net
- Deduction stack hook block / overhaul ball, erected jib, and wire-rope deduction per the chartOSHA 1926.1417(o)
- Flags 75% critical / engineered, 90% margin gone, 100% over chart (STOP)rigging planning practice