Defect Found During Pre-Start Inspection
During the pre-start inspection on a 30 m boom, you find hydraulic fluid weeping from the base of the second boom section's lift cylinder, a frayed wire rope on the boom's emergency lowering system with three broken outer wires over a 40 mm length, and a missing pin retaining clip on the outrigger beam. The machine was used the previous day without reported issues. The pour is scheduled to start in 90 minutes and the concrete is already in transit. The site has no spare machine and the nearest dealer is 200 km away. The supervisor asks you to 'just do the pour and log it afterwards'.
1. Classify each defect and decide the machine's status.
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The hydraulic weep at the lift cylinder base is a potential seal or gland failure. It may be minor now, but a lift cylinder under load is a critical component, and a sudden loss of pressure can drop the boom. It requires inspection by a competent hydraulic technician before the machine is returned to service; it is not a defect to monitor during a pour.
The frayed wire rope on the emergency lowering system is a defect in a safety device. Three broken outer wires over 40 mm in a rope of that size is likely beyond the discard criteria in the relevant rope inspection standard, but the decision must be made against the manufacturer's specification and a competent rope inspector's assessment. A safety device that may fail when needed is not a safety device.
The missing pin retaining clip on the outrigger beam is a positive-locking defect. A pin that can walk out under load can cause an outrigger to collapse, so the machine must not be set up until it is replaced.
Taken together, the machine is out of service. Any one of the three defects is sufficient to stop work.
2. How do you handle the supervisor's instruction and the concrete in transit?
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I decline the instruction and state the basis: the defects affect boom retention, emergency lowering and outrigger locking, and operating with them creates a risk of death or serious injury that no schedule pressure justifies. I record the refusal, the defects and the instruction in the site diary and notify the PCBU.
For the concrete in transit, the practical options are to divert the trucks to another site, to discharge into a designated washout or waste area if the mix is still within its workability window and the supplier agrees, or to return the load. I would contact the supplier immediately, before the trucks arrive, so they can divert rather than wait. The cost of wasted concrete is trivial against the cost of a boom collapse.
I would also ask why yesterday's use did not report these defects, since the weep and the rope damage may have been present then. That is a maintenance and inspection system issue, not just a today issue.
3. What should happen before the machine is returned to service, and what records are required?
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The lift cylinder must be inspected and repaired or cleared by a competent hydraulic technician, with the repair documented. The emergency lowering rope must be assessed against the manufacturer's discard criteria and replaced if it fails, by a competent person, with the replacement rope's certification retained. The outrigger pin retaining clip must be replaced with the correct part, and the pin and its housing inspected for wear or elongation that might have caused the clip to be lost.
After repair, the machine should have a functional test of the boom, the emergency lowering system and the outrigger locking before returning to work, and the test should be recorded. The records required are the defect report, the repair records and parts used, the post-repair inspection and test results, and the maintenance log entry. The person who clears the machine for service should be named.
I would also review the pre-start inspection process to find out why the defects were not caught the previous day, and whether the inspection is being done properly or signed off without being performed.