Survey Requirements:

Auxiliary boilers are surveyed by an authorized Classification Society surveyor every 2 years, with 2 surveys in 5 years (±6 months window).

1. Preparations Before Survey

• Confirm port stay and arrange surveyor’s visit.
• Ensure required tools, spares, and equipment are available.
• If both boilers are to be surveyed, change main engine and diesel generator fuel to diesel oil (D.O.). If only one boiler is surveyed, the other can remain operational.

2. Boiler Isolation & Cooling

• Isolate burner and shut all air, fuel, steam, and feedwater valves; ensure valves are holding.
• Allow boiler to cool, then blow down completely, ensuring no vessels are nearby.
• At ~1 bar pressure, open vent to speed cooling and prevent vacuum formation in boiler.
• Open burner, swivel doors, and inspection openings for ventilation.
• Monitor furnace tube temperature with a temperature gun; when equal to engine room temperature and under negative pressure, drain remaining water to bilge.
• Only after complete drainage, open manholes.

3. Safety Precautions for Internal Inspection

• Carry out risk assessment and obtain enclosed space entry permit.
• Ventilate furnace for several hours before entry.
• Test atmosphere with multi-gas meter.
• Use only low-voltage lighting and intrinsically safe torches inside.
• Maintain standby personnel with radio communication during entry.

4. Cleaning & Internal Checks

• Remove sludge, soot, ash, and scale using approved equipment.
• Inspect and repair refractory brickwork if damaged.
• Gauge boiler tubes and check for pitting, corrosion, or deformation.
• Examine steam drum and water drum internally and externally.

5. Mountings & Accessories

• Dismantle and visually inspect all mountings, including safety valves.
• Replace defective parts only with genuine spares.
• Keep safety valves separately for surveyor’s examination.

6. Surveyor’s Inspection

• Surveyor will visually inspect gas side, water side, mountings, and compare with records.
• On approval, proceed with reassembly.

7. Reassembly & Hydraulic Test

• Before closing manholes, ensure no tools or debris remain inside.
• Refit mountings and box up gas and water sides.
• If hydraulic test required:
  • Fill boiler completely with water.
  • Pressurize to 1.5 × design pressure using hydraulic pump.
  • Hold pressure and check for leaks; pass if no defects found.

  8. Operational Test

  • Fill boiler to ~⅓ glass level.
  • If other boiler operational, circulate steam for slow heating; otherwise, raise steam per maker’s procedure.
  • At ~2 bar, close vent.
  • Set safety valves to design pressure + max 3% tolerance.
  • Record settings in presence of surveyor.
  • Test all safety trips and alarms:
    • High pressure trip
    • Low water alarm and trip
    • High water level trip
    • Ignition flame failure trip
    • Pilot burner failure trip

    9. Final Safety Valve Test

    • Temporarily bypass high-pressure trip.
    • Pressurize boiler until safety valves lift at set pressure.
    • If valves lift correctly and all tests pass, survey is successfully completed.