Inspection Schedule Overview

A cement plant in Malaysia ignored their silo inspection schedule for 3 years. When we finally inspected, we found 40% wall loss in the lower shell from internal corrosion. The $180,000 emergency repair and 2-week shutdown could have been prevented with $5,000 annual inspections. That case taught us: inspection schedules aren't optional, they're insurance.

Inspection frequency framework: Daily visual checks by operators (5 minutes). Monthly detailed inspections by maintenance staff (2-4 hours). Annual professional inspections by engineers (1-2 days). 5-year comprehensive assessment (1 week). Document all findings and track trends over time.

Daily Inspection Checklist

Visual observation walkaround: Check for rust spots or coating damage on shell. Look for unusual shell distortion or bulging. Inspect foundation for cracking or settlement. Verify no water pooling around base. Listen for unusual noise or vibration during filling/discharge.

Operational verification: Confirm level instrumentation reads correctly. Check discharge equipment operates smoothly. Monitor dust emissions from vents. Record filling and discharge rates. Verify safety equipment is in place and functional.

Monthly Maintenance

Shell inspection: Use ultrasonic thickness gauge at suspect areas (focus on lower shell and hopper). Check all bolts for tightness (especially anchor bolts). Verify expansion joints are clean and functional. Inspect paint/coating condition and document any damage.

Roof and accessories: Check roof for leaks or ponding water. Inspect vents and filters for blockage. Verify hatches open and close properly. Test emergency vent operation. Check all safety equipment is accessible.

Annual and 5-Year Inspections

Annual professional inspection: UT thickness measurements at 20+ points on shell and hopper. Plumb survey to check verticality. Foundation settlement survey. Anchor bolt torque verification. Weld visual inspection at critical locations (shell-to-hopper, connections).

5-year comprehensive assessment: Detailed thickness survey covering entire shell. Remaining life assessment based on corrosion rates. Structural analysis update with current conditions. Foundation integrity evaluation. Repair/replacement recommendations with cost estimates.

Frequently Asked Questions

Q: Can we extend inspection intervals if the silo looks fine?

A: No. Internal corrosion often shows no external signs. Stick to the schedule regardless of visual condition.

Q: Who should perform annual inspections?

A: Annual inspections should be performed by qualified structural engineers with silo experience. Daily and monthly checks can be done by trained operators.