Post-Storm Return to Service With Multiple Defects
After a two-day storm with a recorded gust of 30 m/s, a tower crane that was left in the specified out-of-service condition is due to resume work at 06:00. The pre-shift walk-around finds: the jib anemometer cups are missing and the display reads 0 m/s while the ground gauge reads 9 m/s; four broken wires are visible in one strand over one lay length of the hoist rope near the lower sheave; and there is a 3 mm gap at one mast splice, with two bolts showing less thread than the others. The hoist brake otherwise holds a test load. The site supervisor wants to start because the concrete crew is waiting. The operator must decide what is safe and what must happen before the crane is returned to service.
1. Prioritise the findings and decide whether the crane can be returned to service for the afternoon shift.
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The crane should not be returned to service on the basis of this inspection. The anemometer is a safety device: with cups missing and a zero reading while the ground gauge shows 9 m/s, the operator has no reliable jib-height wind information. That alone prevents normal operation until the instrument is repaired or replaced and calibrated. The four broken wires in one strand over one lay length near the lower sheave are a rope condition that must be assessed against the manufacturer's rope inspection criteria and the applicable standard; visible breaks in one strand are a warning, and the rope must be examined for valley breaks, corrosion, diameter loss and sheave damage before any decision. The 3 mm gap and uneven bolt thread at a mast splice are structural findings after a 30 m/s storm. A gap at a splice is not a cosmetic issue; it may indicate loose or yielded bolts, distortion or movement. The hoist brake holding a test load does not offset those findings. All three items require correction and sign-off before the crane is used.
2. For each defect, state the acceptance criteria source and the action required.
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For the anemometer, the acceptance source is the crane manufacturer's manual and the site's operating procedures. The action is to replace or repair the instrument, verify it against a known reference, and confirm the display and alarm functions. The crane should not operate on a ground gauge as a substitute unless the manual expressly provides a verified alternative. For the hoist rope, the acceptance source is the manufacturer's rope inspection and discard criteria, together with the applicable national standard. The action is a detailed inspection by a competent person, including the whole rope length, not just the visible spot. If the rope meets or exceeds a discard criterion, it must be replaced; if it is retained, the reason and measurements must be recorded. For the mast splice, the acceptance source is the manufacturer's bolt torque and gap requirements and the engineer's inspection. The action is to stop use, inspect the bolts and splice for elongation, cracking or distortion, replace damaged bolts, torque to specification and have the repair signed off. A gap that remains after correct torquing requires engineering assessment.
3. What communication and records are required before the crane resumes work?
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The operator should notify the supervisor and the competent person immediately, in writing if the site has a defect-reporting form, that the crane is out of service and why. The concrete crew and other trades should be told that the crane is unavailable so they do not plan lifts around it. Each defect should be entered in the crane log with the time, location, description, photographs where possible, and the name of the person who inspected it. The repair records should identify the parts used, the torque values, the rope measurements and the anemometer calibration. The return-to-service decision should be recorded and signed by the person with the authority to make it. If the supervisor pressures the operator to start, the operator should repeat the specific defects and the reason for the stop-work decision, and escalate to site safety or management. A verbal 'it's fine' is not an acceptable record for a structural or safety-device defect.