Tower Crane Dismantling Method Statement

Tower Crane Dismantling Method Statement is a high-level safety document that details the specific sequence, equipment, and precautions required to safely decommission a tower crane. Because dismantling is a high-risk operation involving heavy loads at height, strict adherence to a pre-approved sequence is critical to maintain structural balance. 1. Pre-Dismantling Preparation

Before any physical work begins, the following administrative and site checks must be completed: Permits & Compliance : Obtain a valid Permit to Work (PTW)

and ensure all personnel have undergone site-specific safety induction. Weather Monitoring

: Verify that wind speeds are below the manufacturer's limit—typically less than . If conditions worsen, operations must stop immediately. Exclusion Zones

: Establish and barricade an exclusion zone on the ground to prevent unauthorized entry under the lifting radius. Equipment Inspection

: Confirm the assisting mobile crane has sufficient capacity and valid certification. 2. Standard Dismantling Sequence Tower Crane Dismantling Procedure | PDF - Scribd

A Tower Crane Dismantling Method Statement is a critical safety document that details the sequence, equipment, and precautions required to safely take down a crane. It typically follows a reverse order of erection, starting from the hook and moving down to the foundation. 1. Preliminary Preparations tower crane dismantling method statement

Before any physical work begins, specific site conditions and administrative checks must be met:

Site Survey & Risk Assessment: A full site survey is conducted to identify hazards like adjacent buildings, power lines, or street furniture.

Weather Monitoring: Dismantling must stop if wind speeds exceed specific limits (typically 25 km/h or 14 m/s).

Exclusion Zone: A safe zone must be barricaded, with warning signs and guards to prevent unauthorized entry.

Permit to Work (PTW): Ensure all necessary permits and third-party certifications for equipment and personnel are in place. 2. Equipment & Personnel

Personnel: Only qualified professionals (erectors, riggers, and signalmen) who are medically fit should be involved. Tower Crane Dismantling Method Statement is a high-level

Mobile Crane: A larger mobile crane (e.g., 150T or 160T) is often used to lower heavy sections like the jib and counter jib.

Communication: Continuous radio or hand signal communication must be maintained between the operator, ground crew, and safety officer. 3. Standard Dismantling Sequence While specifics vary by crane model (like the Potain MCi 85 or Zoomlion 6517 ), the general top-down steps are:

Hook & Hoist: Remove the hook block and reeve the hoist rope back onto the drum.

Counterweights: Use a mobile crane to remove the rear counter ballast blocks one by one to maintain balance.

Front Boom (Jib): Sling and dismantle the jib in sections, often using the mobile crane to lower them to the ground.

Operator's Cabin & Slewing Unit: Dismantle the cab, turntable, and slewing mechanism. or fog impairing visibility.

Mast Sections: Remove tower/mast sections one by one. If using a climbing frame (telescoping cage), it is used to lower the top sections within reach of a mobile crane.

Chassis & Foundation: Finally, dismantle the base frame, outriggers, or bogies and clear all debris from the site. 4. Safety Checks During Work

Balance: Always ensure the crane is in balance before unpinning major components. Use trolleying to fine-tune balance if needed.

Stored Energy: Safely release any stored energy (e.g., hydraulic pressure or tensioned cables) before disassembly.

Lifting Accessories: Inspect all slings, chains, and shackles—the 3-3-3 rule suggests taking 3 seconds to inspect before every lift. Tower Crane Dismantling Procedure | PDF - Scribd

8. Post-Dismantling Checks

Once the last piece is on the ground, the method statement requires:

  • Inventory of all components (match against manufacturer’s parts list).
  • Inspection for damage (cracks, bent flanges, missing pins).
  • Cleaning and packing of bolts and small parts into labeled crates.
  • Sign-off by Appointed Person and Site Manager.
  • Update of site traffic plan – removal of exclusion zones.

2. Pre-Dismantling Requirements – The Critical Checklist

Before any bolt is loosened or section lifted, a thorough pre-dismantling audit must be completed and documented.

2.3 Weather Limitations

  • Wind speed is the #1 enemy. Dismantling must stop if wind exceeds 20 mph (32 km/h) for general operations, or 15 mph (24 km/h) when handling large components like the jib.
  • No lightning, heavy rain, or fog impairing visibility.

Step 3: Dismantle the Jib (Main Boom)

  • Attach the mobile crane’s hook to the designated lifting point on the jib.
  • Apply tension (just 1-2 tons) to take the weight.
  • Remove the jib foot pins and tie-bolts.
  • Lift & lower: Carefully slew the jib down to a prepared ground rigging area.
  • Alternative: For self-erecting cranes, the jib is often telescoped down hydraulically.