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Black Liquor Recovery Boilers - An Introduction
Boiler Efficiency and Steam Quality: The Challenge of Creating Quality Steam Using Existing Boiler Efficiencies
Boiler Logs Can Reduce Accidents
Boiler/Burner Combustion Air Supply Requirements and Maintenance
Carbon Monoxide Poisoning Preventable With Complete Inspection
Combustion Air Requirements:The Forgotten Element In Boiler Rooms
Creep and Creep Failures
Description of Construction and Inspection Procedure for Steam Locomotive and Fire Tube Boilers
Ensuring Safe Operation Of Vessels With Quick-Opening Closures
Environmental Heat Exchangers
Factors Affecting Inservice Cracking of Weld Zone in Corrosive Service
Failure Avoidance in Welded Fabrication
Finite Element Analysis of Pressure Vessels
Fuel Ash Corrosion
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Grain Boundaries
Heat Treatment - What Is It?
How to Destroy a Boiler -- Part 1
How to Destroy a Boiler -- Part 2
How to Destroy a Boiler -- Part 3
Identifying Pressure Vessel Nozzle Problems
Inspection, Repair, and Alteration of Yankee Dryers
Inspection, What Better Place to Begin
Laminations Led to Incident
Lay-up of Heating Boilers
Liquid Penetrant Examination
Low Voltage Short Circuiting-GMAW
Low Water Cut-Off Technology
Low-Water Cutoff: A Maintenance Must
Magnetic Particle Examination
Maintaining Proper Boiler Inspections Through Proper Relationships
Microstructural Degradation
Miracle Fluid?
Organizing A Vessel, Tank, and Piping Inspection Program
Paper Machine Failure Investigation: Inspection Requirements Should Be Changed For Dryer Can
Pipe Support Performance as It Applies to Power Plant Safety and Reliability
Polymer Use for Boilers and Pressure Vessels
Pressure Vessel Fatigue
Pressure Vessels: Analyzing Change
Preventing Corrosion Under Insulation
Preventing Steam/Condensate System Accidents
Proper Boiler Care Makes Good Business Sense:Safety Precautions for Drycleaning Businesses
Putting a Stop to Steam Kettle Failure
Quick Actuating Closures
Quick-Actuating Door Failures
Real-Time Radioscopic Examination
Recommendations For A Safe Boiler Room
Recovering Boiler Systems After A Flood
Rendering Plants Require Safety
Repair or Alteration of Pressure Vessels
Residential Water Heater Safety
School Boiler Maintenance Programs: How Safe Are The Children?
Secondary Low-Water Fuel Cutoff Probe: Is It as Safe as You Think?
Short-Term High Temperature Failures
Specification of Rupture Disk Burst Pressure
Steam Traps Affect Boiler Plant Efficiency
Steps to Safety: Guide for Restarting Boilers after Summer Lay-Up
Stress Corrosion Cracking of Steel in Liquefied Ammonia Service - A Recapitulation
Suggested Daily Boiler Log Program
Suggested Maintenance Log Program
System Design, Specifications, Operation, and Inspection of Deaerators
Tack Welding
Temperature And Pressure Relief Valves Often Overlooked
Temperature Considerations for Pressure Relief Valve Application
The Authorized Inspector's Responsibility for Dimensional Inspection
The Effects of Erosion-Corrosion on Power Plant Piping
The Forgotten Boiler That Suddenly Isn't
The Trend of Boiler/Pressure Vessel Incidents: On the Decline?
The Use of Pressure Vessels for Human Occupancy in Clinical Hyberbaric Medicine
Thermally Induced Stress Cycling (Thermal Shock) in Firetube Boilers
Top Ten Boiler and Combustion Safety Issues to Avoid
Typical Improper Repairs of Safety Valves
Wasted Superheat Converted to Hot, Sanitary Water
Water Maintenance Essential to Prevent Boiler Scaling
Water Still Flashes to Steam at 212
Welding Consideration for Pressure Relief Valves
Welding Symbols: A Useful System or Undecipherable Hieroglyphics?
What Should You Do Before Starting Boilers After Summer Lay-Up?
Why? A Question for All Inspectors


Putting a Stop to Steam Kettle Failure


Yash Nagpaul
Chief Boiler Inspector, State of Hawaii

Spring 1997  

Category: Design/Fabrication 

 

Summary: The following article is a part of National Board Classic Series and it was published in the National Board BULLETIN. (3 printed pages)

 


 

No one wants to experience the effects of a boiler or pressure vessel-related incident. With this in mind, one goal is apparent to every inspector: find a way to prevent the destruction of property, and more importantly, the loss of lives.

Unfortunately a variety of injuries, and even deaths, continue to encumber the boiler and pressure vessel industry, not only in Hawaii but around the world.

For instance, eight years ago a steam kettle exploded in a Hawaii school cafeteria kitchen, injuring one cook. The incident occurred at a time when the cafeteria was not filled with school children.

The investigation revealed that the cook had turned the kettle on and was standing on a step next to the unit, when 10 minutes later, its lid blew off and struck her face. The entire kettle was blown 30 to 40 inches above its footing before falling to the floor. Steam and debris blew about in the immediate vicinity following the accident. No other employees, nor any children, were injured.

It was discovered that the jacketed steam kettle had been losing water for some time and that the water had to be replenished on a regular basis. The school administration had ordered a replacement, but prior to its arrival, the original kettle failed. Surprisingly, the kettle had been in service for only five years.

Following the incident, the remaining four kettles were inspected for corrosion. Serious corrosion was found and the kettles were immediately taken out of service.

After some investigation, it was found that the failed vessel had suffered excessive corrosion in the skirt area and the lower head, therefore causing the failure at a very low pressure. In addition, the vessel failed at the circumference of the head skirt.

Upon this conclusion, the investigation team suggested that the failure may have occurred because of the presence of a silicone-like substance between the decorative vessel skirt and the lower head. The substance may have caused cleansing agents and moisture to collect between the head and skirt. This possibly led to localized corrosion of the carbon steel head, resulting in the kettle?s failure.

The National Board issued an alert after the incident and suggested the following inspection guidelines to help prevent further incidents.

Jacketed Steam Kettle Inspection Guidelines:

 

  1. If the lower head and all pressure parts are fully exposed, external inspection should reveal any apparent problems.

     

  2. If the lower head is concealed by a skirt and is fabricated of carbon steel, inspect for corrosion in the following manner:

     

    1. Check the bottom of the unit. If there is a splash shield covering the lower end, have the shield removed.

       

    2. Examine the lower head. If there is evidence of staining or moisture, there is an excellent chance of corrosion in the skirt area.

       

    3. If there appears to be a seal between the skirt and head, remove a portion and determine if corrosion or debris exists. (This area is very tight and will be difficult to observe. A strong light and mirror are necessary.)

       

    4. If water is added to the jacket manually, check with maintenance to find out how much water is being added and determine the path the liquid follows inside the kettle.

       

Obviously, no pressure-retaining item is immune from the possibilities and dangers of a failure. However, the guidelines mentioned above are designed to greatly reduce the chance of another jacketed steam kettle failure.

 

 

 


 

Editor's note: Some ASME Boiler and Pressure Vessel Code requirements may have changed because of advances in material technology and/or actual experience. The reader is cautioned to refer to the latest edition of the ASME Boiler and Pressure Vessel Code for current requirements.

 







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