Annual Boiler Inspection Guide

Preparation

1. Schedule the shutdown well in advance. Coordinate with production to minimise downtime.
2. Order spare parts in advance: gaskets, sight glass, packing, burner nozzles, refractory materials.
3. Arrange for a certified boiler inspector. In Australia, this may be required by state regulations.
4. Prepare the boiler for shutdown following the proper shutdown procedure (see our Boiler Shutdown Procedure guide).
5. Lock out and tag out all energy sources: fuel, electricity, steam, feedwater, blowdown.
6. Allow the boiler to cool completely before opening. Opening a hot boiler causes thermal shock and burns.
7. Drain the boiler water. Open all access doors and inspection covers.

Fire-Side Inspection

• Tube cleaning: Brush and vacuum all fire-side tubes. Remove soot and ash. Soot is an insulator that reduces heat transfer.
• Tube inspection: Inspect every accessible tube for blistering, cracking, pitting, and erosion. Use a bore scope for tubes that cannot be visually inspected directly.
• Tube wall thickness: Ultrasonically test suspect tubes. Compare to previous readings. Replace tubes with significant thinning.
• Refractory: Inspect refractory lining for cracks, spalling, and deformation. Repair damaged sections. Refractory in poor condition causes hot spots on the boiler casing.
• Burner: Clean and inspect the burner, burner throat, and diffuser. Replace worn nozzles. Check ignition electrode gap.
• Furnace: Inspect furnace walls and floor for cracks, slag buildup, and erosion. Clean and repair as needed.

Water-Side Inspection

• Scale: Inspect all water-side surfaces for scale. Note scale thickness, colour, and distribution. Scale indicates water treatment problems.
• Corrosion: Look for pitting, generalised thinning, and oxygen corrosion. Pay special attention to the water line (where oxygen attack is common).
• Mud drum: Open and clean the mud drum. Remove accumulated sludge and debris. Inspect blowdown connections.
• Steam separation internals: Inspect baffles, demisters, and cyclone separators. Damaged internals cause carryover.
• Water treatment: If significant scale or corrosion is found, have a water treatment specialist review the chemical program.

Testing and Recommissioning

1. Test and recertify all safety relief valves.
2. Calibrate all pressure gauges and temperature sensors.
3. Test all controls: pressure, level, flame, and combustion.
4. Perform a hydrostatic test if major repairs were made (tube replacement, welding).
5. Replace all gaskets on doors and handholes that were opened.
6. Close the boiler, refill with treated water, and follow the startup procedure.
7. Perform a combustion analysis at all firing rates and adjust as needed.
8. Document all findings, tests, and repairs in the boiler logbook and compliance records.