3.6 Lift Planning, Area Control & Rigging Equipment Maintenance

Sub-tasks B-7.04 (Secures area), B-8.01 (Sets up rigging, hoisting/lifting and moving equipment) and B-8.03 (Maintains rigging, hoisting/lifting and moving equipment) complete Major Work Activity B. Section 3.1 through 3.4 covered sling mechanics and signals; this section covers the plan around the lift and the condition of the gear.

The Lift Plan

Every lift needs a plan; a critical lift needs a documented, reviewed and often engineered one. Sites typically define a critical lift as any lift that is over a set percentage of crane capacity (commonly 75–90%), uses more than one crane, lifts over occupied areas or live process equipment, lifts personnel, or involves an unusual or unknown load.

Load Charts and Radius

A mobile crane's capacity is a function of boom length and radius, not a single number. The load chart is the legal capacity document. Points the exam tests:

• Outriggers must be fully extended and set unless the chart specifically provides an on-rubber or partially-extended column; using the fully extended column while the outriggers are short is a fabrication of capacity.
• Deductions for the hook block, ball, slings, jib and any auxiliary equipment come off the chart capacity before the net load is calculated.
• Capacity falls as radius grows, and the load moves out in radius as the boom deflects under load — the radius must be checked loaded, not just at pick-up.
• Tandem (multi-crane) lifts are de-rated, commonly to about 75% of each crane's chart capacity, because load sharing shifts unpredictably as the load moves. They require an engineered plan and a single lift director.

Ground Bearing

Outrigger float pressure concentrates enormous load into a small area. Cribbing or mats spread it:

$\text{Bearing pressure} = \frac{\text{Outrigger load}}{\text{Mat area}}$

Worked example. A 45,000 kg outrigger reaction on a 1.2 m by 1.2 m mat gives 45,000 / 1.44 = 31,250 kg/m², roughly 306 kPa. That must be compared with the allowable bearing capacity of the ground, and larger mats used if it exceeds it. Beware backfilled trenches, buried tanks, basements, culverts and recently disturbed ground — these are where cranes go over.

Securing the Area (B-7.04)

1. Establish an exclusion zone covering the load path, the potential drop zone, and the crane's tail swing. Barricade it and post it.
2. Never lift a load over people, and never allow anyone under a suspended load.
3. Control traffic — vehicle, pedestrian and mobile equipment — with barricades and a spotter, not just tape.
4. Assign one designated signal person, clearly identified, using the standard signals from section 3.4. The operator takes signals only from that person, with one exception: the emergency stop signal is accepted from anyone.
5. Use tag lines to control load rotation, long enough to keep the handler outside the drop zone, and never wrapped around a hand or body.
6. Stop for weather. Most mobile cranes have a manufacturer wind limit, often in the range of 32–40 km/h for normal work and much lower for loads with large sail area. The limit applies at the boom tip, not at ground level.
7. Verify power line clearance and appoint a dedicated spotter; where the minimum approach distance cannot be maintained, the line is de-energized and grounded by the utility.

Rigging Equipment Inspection and Maintenance (B-8.03)

Two levels of inspection apply to all rigging gear:

• Frequent inspection — a visual check by the user before every use.
• Periodic inspection — a documented inspection by a designated qualified person, typically annually, and more often in severe service. Records are kept.

Any sling or item of hardware missing a legible identification tag or capacity marking is immediately out of service, because its rating cannot be established.

Wire Rope Slings — Removal Criteria

Alloy Chain Slings — Removal Criteria

• Only Grade 80 and Grade 100 alloy chain is approved for overhead lifting.
• Remove for stretch beyond the manufacturer's limit — commonly about 3% elongation, measured over a defined number of links against the original reach.
• Remove for nicks, gouges, cracks, twisted or bent links, gouged or worn link bearing points beyond the allowable minimum thickness, stretched or opened hooks, and any evidence of heat damage or weld spatter.
• Never shorten a chain sling with knots, bolts or by wrapping — use only a proper grab hook or shortening clutch.

Synthetic Web Slings and Roundslings — Removal Criteria

• Missing or illegible identification tag
• Acid or caustic burns, or melting or charring of any part
• Holes, tears, cuts, snags or embedded particles
• Broken or worn stitching in load-bearing splices
• Knots in any part of the sling
• Excessive abrasive wear or distortion of fittings
• On a roundsling, exposure of the red core warning yarn through the cover
• Exposure beyond the material limits: 90 C (194 F) maximum and -40 C minimum for nylon and polyester

Protect synthetic slings from cutting with corner protectors, wear pads or sleeves at every edge, and store them out of sunlight, away from chemicals and off the floor.

Shackles

• Use only the manufacturer's original pin. A bolt substituted for a shackle pin is not rated and has failed in service.
• Remove for wear on the bow or pin exceeding about 10% of the original dimension, for a bent or elongated bow, for a distorted or non-turning pin, or for heat damage and weld spatter.
• Never side-load a shackle beyond the manufacturer's reduction chart, and place the pin so the sling bears in the bow, not on the pin threads.

Hooks

A hook that has been spread open is permanently damaged and is scrapped, never re-bent or heated back into shape.

Storage and Records

Store slings on racks, off the ground, out of direct sunlight, away from chemicals and welding areas, and never leave them in a place where they will be run over or dragged. Keep the periodic inspection record for every serialized item, along with proof-test certificates for repaired or altered rigging. Repairs to load-bearing rigging are performed only by the manufacturer or a qualified person, followed by proof testing.