Cranes, Hoists and Rigging

1. Why This Topic Matters

Crane, hoist and rigging incidents are among the most severe and most frequently cited hazards in construction and general industry. A single failure of a sling, a hook, or a load chart judgment can kill multiple people in seconds. OSHA data consistently shows that struck-by loads, crushing during assembly or disassembly, electrocution from power line contact, and crane tip-overs account for the majority of crane fatalities. Because these incidents are high-consequence, low-frequency events, they test exactly what the BCSP CSP exam values in the Advanced Application of Safety Principles domain: the ability to apply engineering standards, perform calculations, plan critical work, and recognize when a lift must not proceed.

For the CSP candidate, this topic blends several skill sets at once: regulatory knowledge (OSHA 29 CFR 1926 Subpart CC, 1910.179, 1910.180, 1910.184), consensus standards (ASME B30 series, ASME P30.1 for lift planning), physics (center of gravity, sling angle tension, leverage and moment), and management systems (lift plans, inspections, operator qualification). Expect questions that require more than recall; you will be asked to calculate, interpret, and decide.

2. What It Is: Core Definitions

Crane: A machine for lifting and lowering a load and moving it horizontally, with the hoisting mechanism as an integral part. Common types include mobile cranes (crawler, rough-terrain, all-terrain, truck-mounted), tower cranes (hammerhead, luffing jib, self-erecting), overhead and gantry cranes (bridge cranes), and articulating boom (knuckle boom) cranes.

Hoist: A device for lifting and lowering only, without horizontal travel as an integral function. Includes chain hoists (manual and electric), wire rope hoists, lever hoists (come-alongs), and air hoists. Overhead hoists are covered by ASME B30.16; base-mounted drum hoists by ASME B30.7.

Rigging: The hardware and practices used to attach the load to the hook. Includes slings (wire rope, alloy steel chain, synthetic web, synthetic roundsling, metal mesh), shackles, eyebolts, hooks, turnbuckles, spreader bars, lifting beams, and swivel hoist rings. Governed by OSHA 1910.184, 1926.251, and ASME B30.9 (slings), B30.10 (hooks), B30.20 (below-the-hook lifting devices), and B30.26 (rigging hardware).

Key roles defined in 1926 Subpart CC:
- Operator: must be certified (by an accredited testing organization, audited employer program, state or local license, or military) and evaluated by the employer per 1926.1427.
- Signal person: must be qualified by a third party or a qualified evaluator per 1926.1428.
- Rigger: must be qualified when working in the fall zone during hook-up or when assembling or disassembling the crane (1926.1404 and 1926.1425).
- Assembly/Disassembly (A/D) Director: a competent and qualified person who supervises crane assembly and disassembly.
- Competent person: capable of identifying hazards and authorized to correct them.
- Qualified person: has a degree, certificate, or extensive knowledge and experience demonstrating the ability to solve problems related to the work.

3. How It Works: The Technical Foundation

3.1 Load Charts and Capacity

The load chart is the single most important document on a crane. It specifies rated capacity as a function of boom length, boom angle, load radius, counterweight configuration, outrigger extension, and quadrant of operation (over front, over side, over rear). Capacity decreases dramatically as radius increases because the overturning moment equals load times radius. Key concepts:

- Gross capacity is the chart value. Net capacity is what you can actually lift after subtracting deductions: the hook block, headache ball, rigging, jib stowed or erected, and any attachments.
- Capacities are typically limited either by structural strength (short radius, high boom angle) or by stability (long radius, low boom angle). Chart values above a bold line or shaded zone are usually structural limits; those below are stability limits. Mobile crane stability-limited capacities are generally 85 percent of the tipping load for crawlers on tracks and 75 percent for outrigger-supported cranes.
- Load radius is measured from the center of rotation (center pin), not from the boom foot, to the center of the load after the boom has deflected under load.
- Never extrapolate between chart values; use the next lower capacity.

3.2 Load Weight Determination

Before any lift you must know the load weight. Sources in order of preference: manufacturer data plates or shipping documents, engineered drawings, calculation from dimensions and material density, or direct weighing with a load cell or dynamometer. For calculations, remember common densities: steel is approximately 490 lb per cubic foot (0.2833 lb per cubic inch), concrete approximately 150 lb per cubic foot, water 62.4 lb per cubic foot, aluminum approximately 165 lb per cubic foot. Total hook load equals load plus all rigging plus the block or ball.

3.3 Center of Gravity (CG)

For a stable lift the hook must be positioned directly above the CG. If it is not, the load will tilt until the CG hangs beneath the hook, shifting tension unevenly among sling legs and potentially causing a sling to slip or overload. For asymmetric loads, use unequal sling lengths or a lifting beam, and calculate each leg's share of the load based on distance from the CG (the leg closer to the CG carries the greater share, inversely proportional to distance).

3.4 Sling Angle and Tension

This is the most frequently tested rigging calculation. As the angle between the sling leg and the horizontal decreases, tension in each leg increases. The formula for a symmetrical two-leg bridle with legs at angle A to the horizontal:

Tension per leg = (Load divided by number of legs) divided by sin(A)

Equivalently, use a load angle factor (LAF) = 1 divided by sin(A):
- 90 degrees (vertical): LAF 1.000
- 60 degrees: LAF 1.155
- 45 degrees: LAF 1.414
- 30 degrees: LAF 2.000

Example: A 4,000 lb load is lifted with a two-leg bridle at 60 degrees to horizontal. Tension per leg = (4,000 divided by 2) divided by 0.866 = 2,000 times 1.155 = 2,309 lb. At 30 degrees the same lift puts 4,000 lb in each leg, equal to the full load weight in every leg. ASME B30.9 and OSHA 1926.251 prohibit sling angles below 30 degrees from horizontal. Also note that with three or four leg bridles, you should assume only two legs carry the load unless the rigging is designed to equalize (for example with a rigid load, only two or three legs may be loaded at any moment).

3.5 Hitch Types

- Vertical (straight) hitch: sling rated at 100 percent of its vertical capacity.
- Choker hitch: sling wraps around the load and back through its own eye; capacity reduced to roughly 75 to 80 percent of vertical rating, and reduced further if the choke angle is less than 120 degrees.
- Basket hitch: sling cradles the load with both ends on the hook; capacity up to 200 percent of vertical rating when legs are vertical, reduced by the sling angle factor as legs spread.
- Always check the D/d ratio for wire rope: the diameter of the object the rope bends around (D) divided by rope diameter (d). Small D/d ratios sharply reduce capacity; many charts assume D/d of 25 or more for full basket capacity.

3.6 Sling Materials and Design Factors

- Wire rope slings: design factor of 5 to 1 minimum. Removal criteria under 1910.184: 10 randomly distributed broken wires in one rope lay, or 5 broken wires in one strand in one rope lay; also kinking, crushing, bird-caging, heat damage, corrosion, end attachment damage.
- Alloy steel chain slings: design factor of 4 to 1. Only Grade 80 or Grade 100 alloy chain is permitted for overhead lifting. Remove for stretch, gouges, cracks, wear beyond manufacturer limits, or heat damage. Must have a permanently affixed identification tag with size, grade, rated load, and reach.
- Synthetic web slings: design factor of 5 to 1. Remove for missing tag, acid or caustic burns, melting or charring, holes, tears, cuts, snags, broken or worn stitching, excessive abrasive wear, knots, or red core warning yarns showing. Nylon is damaged by acids; polyester is damaged by alkalis. Both degrade from UV exposure and have temperature limits around 194 degrees F (90 degrees C).
- Synthetic roundslings: design factor of 5 to 1; the cover protects the load-bearing core yarns; any cover damage exposing core yarns requires removal.
- Metal mesh slings: suitable for hot or abrasive loads; design factor 5 to 1.

3.7 Rigging Hardware

- Shackles: use screw pin for non-rotating applications; use bolt-type (safety) shackles where the pin may rotate or in long-term installations. Never replace a shackle pin with a bolt. Side loading reduces capacity; many manufacturers derate 30 percent at 45 degrees and 50 percent at 90 degrees side load. Center the load on the bow, not the pin, when multiple slings are used.
- Eyebolts: shoulder-type eyebolts are required for angular loading and must be fully seated; non-shoulder eyebolts are for vertical loads only. Angular loading drastically reduces capacity (roughly 30 percent of rated at 45 degrees for many designs); swivel hoist rings are preferred for angular pulls.
- Hooks: must have a working latch unless a qualified person determines otherwise for a specific application. Remove from service for cracks, throat opening increased more than 15 percent, twist exceeding 10 degrees from the plane of the unbent hook, wear exceeding 10 percent of original dimension, or any heat damage or unauthorized repair.
- Below-the-hook lifting devices (spreader bars, lifting beams, plate clamps, vacuum lifters, magnets): governed by ASME B30.20; must be marked with rated load, weight, and manufacturer; designed to a minimum design factor of 3 to 1 based on yield for Design Category A, higher for more severe service.

3.8 Crane Setup and Stability

- Ground conditions: the controlling entity must provide adequate ground conditions and inform the crane user of hazards beneath the surface (voids, utilities, tanks). Outrigger pads, cribbing, or mats distribute load; ground bearing pressure equals outrigger load divided by pad area. Outriggers must be fully extended or deployed as specified in the load chart being used, with the crane level (typically within 1 percent of level, about 1 degree).
- Leverage and moment: overturning moment equals load times radius; resisting moment comes from machine weight and counterweight acting about the tipping fulcrum (the outrigger float or track edge). Boom deflection increases radius under load.
- Swing radius: the rotating superstructure can crush workers against fixed objects; barricade the swing radius and address the hazard in training.
- Wind: follow manufacturer limits; many cranes stop operations around 20 to 30 mph, lower for large sail-area loads. Tower cranes have specific out-of-service wind limits and must be allowed to weathervane.
- Two-blocking: contact between the load block and the boom tip sheave can part the hoist line and drop the load. Anti-two-block devices are required on most mobile cranes under 1926.1416.
- Load moment indicator (LMI) or rated capacity indicator and boom angle and radius indicators are required on cranes above certain capacities; they are operator aids and do not replace the load chart.

3.9 Power Line Safety (1926.1407 through 1926.1411)

Electrocution remains a leading crane fatality cause. The rule requires the employer to first determine whether any part of the crane, load line, or load could get closer than 20 feet to a power line if operated up to maximum working radius. If so, one of three options applies: de-energize and ground the line, maintain a 20 foot clearance with encroachment-prevention measures, or determine the line voltage and maintain the Table A minimum clearance with encroachment-prevention measures. Table A minimum clearance distances:
- Up to 50 kV: 10 feet
- Over 50 to 200 kV: 15 feet
- Over 200 to 350 kV: 20 feet
- Over 350 to 500 kV: 25 feet
- Over 500 to 750 kV: 35 feet
- Over 750 to 1,000 kV: 45 feet
- Over 1,000 kV: as established by the utility owner or a registered engineer
Encroachment prevention measures include a planning meeting, a dedicated spotter, proximity alarms, range control warning devices, range limiting devices, insulating links, and elevated warning lines or barricades. If contact occurs, the operator should stay in the cab unless fire forces exit, in which case jump clear with feet together and shuffle away.

3.10 Inspections

Crane inspections under 1926.1412 and ASME B30.5:
- Shift inspection: visual inspection by a competent person before each shift for deficiencies.
- Monthly inspection: documented, by a competent person, records retained a minimum of three months.
- Annual (comprehensive) inspection: by a qualified person, documented, records retained a minimum of twelve months.
- Post-assembly, modified or repaired equipment, and equipment not in regular use (idle more than three months) require specific inspections.
- Overhead and gantry cranes (1910.179) use frequent (daily to monthly) and periodic (one to twelve months) inspection intervals; running ropes are inspected monthly with a certification record.
- Rated load tests: new or altered overhead cranes are tested at not more than 125 percent of rated load; mobile crane load tests follow manufacturer and ASME requirements.

Rigging inspections: each day before use by a competent person (1926.251 and 1910.184), plus periodic inspections by a qualified person at intervals based on service severity (at least annually; more frequently for severe service), documented for chain slings. Slings with missing or illegible identification tags must be removed from service.

3.11 Critical Lifts and Lift Planning

A critical lift is typically defined by site or corporate policy as any lift exceeding 75 percent of the crane's rated capacity in the configuration used, lifts using two or more cranes (multiple-crane or tandem lifts), lifts of personnel, lifts over or near energized equipment, occupied structures, or critical process lines, lifts with unusual or unknown CG, and lifts where failure would cause unacceptable consequences. Critical lifts require a written, engineered lift plan reviewed and signed by qualified persons. ASME P30.1 provides a framework for lift planning at the standard, critical, and engineered levels. A good lift plan includes: load weight and CG, crane model and configuration, boom length and angle, radius at pick and set, gross and net capacity with percent of capacity, rigging components and their ratings, sling angles and calculated tensions, ground bearing pressure and matting, power line and obstruction survey, wind limits, communication method, exclusion zones, and roles and responsibilities. For tandem lifts, load sharing must be calculated and each crane is commonly limited to 75 percent of chart capacity to allow for dynamic load shifting.

3.12 Communication and Signals

Hand signals must conform to the standard method (the ASME B30 charts, posted at the job site). Only one person gives signals at a time, except that anyone may give the emergency STOP signal. Voice signals must include three elements: function and direction, distance or speed, and function stop. Radio or electronic signals require a dedicated channel and a pre-lift check of equipment. If communication is lost, the operator must stop until it is restored.

3.13 Personnel Hoisting

Hoisting personnel with a crane is prohibited unless conventional means (ladders, scaffolds, aerial lifts) would be more hazardous or are not possible (1926.1431). Requirements include a designed and marked personnel platform, a trial lift with the unoccupied platform, a proof test at 125 percent of the platform's rated capacity, pre-lift meeting, total load not exceeding 50 percent of the crane's rated capacity, operator remaining at the controls, anti-two-block device, power-controlled lowering (no free fall), and fall protection for occupants.

3.14 Hoists and Overhead Cranes in General Industry

For 1910.179 overhead and gantry cranes: rated load markings on each side of the crane and on each hoist; bridge and trolley bumpers; rail sweeps; brakes capable of holding 125 percent of rated load for hoists; hook latches; preventing side pulls (hoist line must be vertical, do not drag loads); warning devices for cab-operated cranes; and lockout for maintenance with the crane moved to a location where it will not interfere with other cranes. Manual chain hoists and lever hoists must never be extended with cheater bars, must not be used with the load chain twisted or wrapped around the load, and must be inspected for stretched or worn chain and correct brake operation.

3.15 Assembly, Disassembly and Common Fatal Errors

Crane assembly and disassembly must be directed by an A/D Director who follows manufacturer procedures or employer procedures developed by a qualified person. Workers must not be under the boom, jib, or other components unless the A/D Director has confirmed they are supported and the work cannot be done otherwise. Boom pins removal order and pendant tension are classic failure points. Other frequent fatal errors: lifting with outriggers partially extended while using the fully extended chart, using the wrong quadrant chart, failing to account for the jib and block weight, operating on soft or undermined ground, picking a load from the side (side loading the boom), permitting workers in the fall zone, and swinging a load over people.

4. How to Answer Exam Questions on Cranes, Hoists and Rigging

Step 1: Identify what the question is really testing. Most crane and rigging items fall into one of five buckets: a calculation (sling tension, net capacity, load weight, ground bearing pressure), a regulatory threshold (clearances, inspection intervals, removal criteria), a hierarchy or decision (what must happen first, who is responsible), a hazard recognition scenario (what is wrong with this lift), or a management system element (what belongs in a critical lift plan). Label the bucket before you read the choices.

Step 2: For calculations, write the formula before touching numbers. Draw a quick sketch of the load and sling legs. Convert all angles to angles from horizontal (the standard reference in rigging tables). Divide the load by the number of legs assumed to carry it, then multiply by the load angle factor. Check whether rigging weight must be added to the hook load. Compare your result to the sling rating using the correct hitch type (vertical, choker, basket).

Step 3: For capacity questions, remember gross versus net. Read the chart value for the configuration described, then subtract block, rigging, and attachments. The exam frequently hides a deduction in the stem. Also confirm that the configuration described (outrigger extension, counterweight, quadrant) matches the chart cited; a mismatch is often the intended answer.

Step 4: For regulatory thresholds, know the exact numbers. Memorize: 20 foot initial power line trigger distance; Table A clearances (10, 15, 20, 25, 35, 45 feet); 30 degree minimum sling angle; 10 broken wires per lay or 5 per strand per lay for slings; 15 percent hook throat opening and 10 degree twist; 125 percent load test; 75 percent critical lift threshold; 50 percent capacity limit for personnel platforms; monthly inspection records kept three months and annual records kept twelve months; design factors 5 to 1 for wire rope and synthetics and 4 to 1 for alloy chain.

Step 5: For scenario questions, apply the hierarchy of controls and the worst-credible-outcome lens. When several answers seem reasonable, select the one that eliminates the hazard (de-energize the line, remove the load from over workers, replace the damaged sling) over the one that merely warns or trains. If the question asks what to do first, the answer is nearly always to stop the lift and secure the load, or to verify the load weight and chart capacity before lifting.

Step 6: For role and responsibility questions, match the role to the standard. Operator certification is the operator's credential and the employer's evaluation; signal person qualification is documented by a qualified evaluator or third party; the controlling entity ensures ground conditions; the A/D Director supervises assembly; the competent person performs shift and monthly inspections; the qualified person performs the annual inspection and develops procedures and engineered lift plans.

Step 7: Eliminate distractors that violate physics. Any answer implying that lowering the sling angle (flatter legs) reduces tension, that side loading a shackle or boom is acceptable, that a choker hitch has full vertical capacity, that a longer boom at the same angle increases capacity, or that an LMI replaces the load chart is wrong.

5. Exam Tips: Answering Questions on Cranes, Hoists and Rigging

Tip 1: Master the sling tension calculation cold. It appears in some form on nearly every version of the exam. Practice with 30, 45, and 60 degree angles until the load angle factors of 2.000, 1.414, and 1.155 are automatic. Remember that a 30 degree angle doubles the tension and is the regulatory floor.

Tip 2: Angles are from the horizontal. If a question gives the angle from vertical, convert it (90 minus the given angle). If it gives the included angle between two legs of a symmetric bridle, each leg's angle from horizontal is 90 minus half the included angle.

Tip 3: Watch for unit and dimension traps. Load weights may be given in kilograms or tons; sling ratings in pounds. One short ton equals 2,000 lb, one metric ton equals 2,204.6 lb, one kilogram equals 2.205 lb. Volumes may need conversion from inches to feet before applying density.

Tip 4: Radius, not boom length, controls capacity. When a question changes the boom angle, think about how the radius changes. Lowering the boom increases radius and lowers capacity; raising the boom reduces radius and increases capacity until structural limits govern.

Tip 5: Deductions come off the chart, every time. If the stem mentions a jib, block, headache ball, spreader bar, or rigging weight, subtract it before comparing to the load. If the question asks the percentage of capacity, use net capacity.

Tip 6: Know the three power line options in order. De-energize and ground; maintain 20 feet; or determine voltage and maintain Table A distance. In each case the employer must still implement encroachment-prevention measures. The exam loves the 10 foot value for lines up to 50 kV.

Tip 7: Memorize removal criteria as pairs. Wire rope sling: 10 in a lay, 5 in a strand. Hook: 15 percent throat, 10 degree twist. Synthetic sling: red core yarn visible means remove. Chain: measure for stretch against manufacturer limits, never estimate by eye alone.

Tip 8: Differentiate competent from qualified. Daily and monthly inspections, shift checks, and rigging inspections are competent person tasks. Annual inspections, lift plan engineering, and below-the-hook device design are qualified person tasks. Questions often swap these to create distractors.

Tip 9: For critical lifts, the answer usually includes a written plan and a pre-lift meeting. If a scenario describes two cranes, a lift near 75 percent or more of capacity, personnel on the hook, or a lift over an occupied process area, the best answer will involve engineered planning, defined roles, and verification steps rather than reliance on operator experience.

Tip 10: Personnel hoisting is the last resort. If the question asks whether a crane-suspended platform may be used, the answer hinges on whether conventional means are more hazardous or infeasible, and the follow-on requirements are the trial lift, 125 percent proof test, and 50 percent capacity limit.

Tip 11: Stop means stop. Any answer in which the operator continues the lift after losing communication, after an unexpected load swing, after the LMI alarms, or after a worker enters the fall zone is wrong. Anyone may give the emergency stop signal.

Tip 12: Think like the standard writer. OSHA Subpart CC and ASME B30 are built around a sequence: assess ground and power lines, set up per manufacturer, inspect, plan the lift, verify weight and capacity, rig correctly, communicate, keep people out of the fall zone, and never free-fall a load. When a question asks for the best or first action, trace that sequence and find where the scenario broke it.

Tip 13: Manage your time. Calculation questions deserve two to three minutes; do them carefully but do not let one problem consume the time budget. If you are stuck, eliminate the answers that violate physics or exceed known regulatory numbers, pick the most conservative remaining option, flag the item, and move on.

6. Quick Reference Summary

- Sling tension per leg = (Load divided by legs) times (1 divided by sin of angle from horizontal)
- Load angle factors: 90 deg 1.00; 60 deg 1.155; 45 deg 1.414; 30 deg 2.00; below 30 deg prohibited
- Design factors: wire rope and synthetic 5:1; alloy chain 4:1; below-the-hook devices 3:1 on yield minimum
- Hitch capacities: vertical 100 percent; choker about 75 to 80 percent; basket up to 200 percent
- Power lines: 20 ft assessment trigger; 10 ft up to 50 kV; 15 ft to 200 kV; 20 ft to 350 kV; 25 ft to 500 kV; 35 ft to 750 kV; 45 ft to 1,000 kV
- Wire rope sling removal: 10 broken wires in one lay or 5 in one strand in one lay
- Hook removal: throat opening increase greater than 15 percent or twist greater than 10 degrees
- Inspections: shift (competent), monthly (competent, keep 3 months), annual (qualified, keep 12 months)
- Load test: 125 percent of rated load; personnel platform proof test 125 percent; personnel lift limited to 50 percent of crane capacity
- Critical lift: commonly 75 percent or more of chart capacity, multi-crane, personnel, or high-consequence lifts; requires written engineered plan
- Stability: overturning moment equals load times radius; outrigger charts assume full extension and level within about 1 percent
- Operator certified and employer evaluated; signal person qualified; rigger qualified; A/D Director competent and qualified

Approach every crane, hoist, and rigging question by asking four things: What is the true hook load? What is the true net capacity in this configuration? Is every rigging component rated for its actual tension and hitch? And has every mandatory prerequisite (ground, power lines, inspection, communication, exclusion zone) been satisfied? If you can answer those four questions, you can answer the exam's.