# Cooling Tower Rigging Trainer Shopfloor training: rig a modular cooling tower section to an overhead crane with a spreader bar and slings, test lift it and set it down By James Levin Topic: Engineering [Open the interactive Jig](https://ask.jig.com/j/igRYXYpXA352) ## Guide ### 1. Cooling Tower Rigging Trainer This basin section of a modular evaporative cooling tower is waiting on timber cribbing\. You will rig it to the overhead crane with a spreader bar and four wire rope slings, make a test lift and set it on its support steel\. Drag anywhere away from the rigging to turn the view\. Weights, sizes and offsets here are illustrative, for training only\. Always follow the manufacturer's rigging instructions and your site's lift plan\. ### 2. Pre\-lift inspection Inspect the gear and the load before anything is hooked up\. Check each lifting ear for cracks, bending and worn holes\. Check every sling and shackle for a legible capacity tag, broken wires, kinks and bent pins\. Make sure the hook latch closes and the support steel is level and clear\. Press Inspect to walk through the checks\. Take damaged or unmarked rigging out of service\. Never use a sling without a readable capacity tag\. ### 3. Choose the lifting points Lift only from the lifting ears the manufacturer provides: here, four plates on the top rails near the corners\. Click each ear to shackle a sling to it\. Click anywhere else on the section, such as a rail, a louver or a panel, to see why that is the wrong point\. Rails, louvers and panels are not built to carry the module's weight\. They can bend or tear out, and the load can slip\. ### 4. Set the sling angle The spreader bar hangs from two upper slings\. Move the slider to change their angle from the horizontal and watch the load in each sling\. Hanging straight down, each sling would carry half the weight\. As the slings flatten, that load grows fast: 1\.15 times at 60 degrees, 1\.41 times at 45 degrees and twice as much at 30 degrees\. Green is 60 degrees or more, amber is 45 to 60, red is below 45\. Readings assume an illustrative 12,000 lb module\. ### 5. Spot the mistakes Compare a correct rig with the two most common mistakes\. Wrong points: slings wrapped round the top rail instead of shackled to the ears, so the rail bends and the slings can slide\. Too shallow: a long, flat sling angle that nearly triples the tension in each sling and pulls the ears sideways\. If the rig does not match the lift plan, stop and correct it before taking any weight\. ### 6. Check the centre of gravity The sump end of this basin is heavier, so its centre of gravity is not in the middle\. A load always swings until its centre of gravity hangs straight below the hook\. With the hook over the middle, the section tilts as it leaves the cribbing\. Move the hook over the centre of gravity and it hangs level\. The offset here is illustrative\. Take the real centre of gravity from the manufacturer's data or the lift plan, and adjust the rig before lifting\. ### 7. Make a test lift Take up the slack slowly, then raise the section a few inches clear of the cribbing and hold it\. Check that it hangs level, that nothing slips or stretches and that the crane brake holds\. If anything is wrong, lower it and fix the rig before going on\. Keep everyone clear of the load and never stand under it\. Use tag lines to control any swing\. ### 8. Set the module down Lift only as high as you need, travel slowly and smoothly to the support steel and lower the section onto it, lining it up as it lands\. Keep the slings attached until the section is bolted down\. This tower's rigging bulletin calls for a hook height of at least 26 feet above the section, and bottom sections are bolted to the steel before any upper section is rigged\. ### 9. Quiz 1 of 4: Lifting points Where should the slings be attached to lift this section? Choose an answer\. A green tick or a red cross appears above the section\. ### 10. Quiz 2 of 4: Sling load Two slings lift a 12,000 lb load, each at 30 degrees from the horizontal\. About how much does each sling carry? ### 11. Quiz 3 of 4: Hook position Where should the hook be before the section leaves the ground? ### 12. Quiz 4 of 4: Unhooking The section is resting on its support steel\. When can the slings be removed?