Boiler Accidents: Comprehensive Cause Analysis And Preventive Measures (Part 1)

Boilers operate under high temperature and high pressure conditions and are prone to catastrophic failures such as explosions or ruptures due to improper operation or equipment defects. These accidents can cause serious property losses, production shutdowns and casualties. Understanding the classification, causes and preventive measures of boiler accidents is essential to ensure safe operation and compliance with industry standards.

1. Classification of Boiler Accidents

Boiler accidents are classified according to severity, location and cause:

Classification by severity

Explosion accident: The main components (such as drums, headers) suddenly rupture, and the pressure is quickly released into the atmosphere, causing huge damage.

- Major accidents: Events such as pipe bursts, severe deformations, furnace collapse or structural damage require large-scale repairs and shutdowns.

General accidents: Minor failures that cause temporary shutdowns but can be quickly restored to operation, such as valve leaks or minor control failures.

Classification by accident location

Pressure components: Drum explosion, boiler tube rupture.

Auxiliary systems: Economizer leakage, superheater failure, pipeline/duct accidents

Safety components: safety valve, water level gauge or water supply equipment failure.

Classification by root cause

Human error: improper water level management (e.g., lack of water or overfilling), improper combustion control.

Equipment defects: design defects, manufacturing defects or aging of components.

Maintenance issues: corrosion, scaling or insufficient inspection.

2. Common boiler accidents and management

2.1 Explosion accidents**

Causes:

Severe lack of water causes overheating of steel plates; sudden water injection causes thermal shock.

Alkali embrittlement of riveted boilers due to high alkalinity and leakage.

Safety valve failure or design defects cause excessive pressure.

Neglected small boilers in non-industrial environments (e.g., heating systems) that lack appropriate safety controls.

Preventive measures:

Ensure that pressure components meet design requirements (e.g., drum thickness, welding standards).

Check regularly for corrosion, cracks or deformation; perform high-quality repairs to prevent structural damage.

Provide strict training for operators: Never refill an overheated boiler.

- Safety valve maintenance is mandatory; priority is given to small boiler safety for residential/commercial use.

2.2 Water shortage incidents

Symptoms:

Empty water gauge, wrong water level, low water level alarm, increased steam temperature or abnormal noise.

Severe cases: overheating of pipes, collapse of furnace walls or risk of explosion.

Handling:

Minor water shortage: check water level via "water level alarm" (check for water return by closing steam cock).

Severe water shortage: shut down immediately; water replenishment is strictly prohibited to avoid thermal shock.

After shutdown: check heating surfaces, perform pressure test, and solve the root cause (e.g., pressure gauge blockage, water supply failure).

Prevention:

Increase operator vigilance and clean pressure gauges regularly to prevent false readings.

Water level alarm and automatic water supply system operate normally; avoid over-reliance on automation.

Reasonable work arrangement to prevent operator fatigue.

2.3 Water overflow incidents

Symptoms:

Opaque water gauge, high level alarm, reduced steam temperature and water hammer in pipes.

Risks include steam contamination, turbine damage, or superheater scaling.

Treatment:

Stop feedwater, reduce combustion, and drain excess water through the blowdown valve.

Severe cases: Emergency shutdown, inspect pipe damage, and resume operation after resolving the problem.

Prevention:

Same as water shortage measures, focus on operator training and instrument maintenance.

3. Part I Highlights

This section covers the basic classification of boiler accidents and three key events: explosion, water shortage, and flooding. Key strategies include strict design standards, operator training, and proactive maintenance. In **Part II**, we will delve into steam water startup, pipe rupture, and auxiliary system failures, and explore their mechanisms and prevention measures.