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A Boiler: The Explosive Potential of a Bomb
Acoustic Emission Examination of Metal Pressure Vessels
Anatomy of a Catastrophic Boiler Accident
Austenitic Stainless Steel
Auto-Refrigeration
Basic Weld Inspection - Part 1
Basic Weld Inspection - Part 2
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
Fuel Firing Apparatus - Natural Gas
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


Why? A Question for All Inspectors


Lee Doran
National Board Consultant

Fall 1993  

Category:  Operations

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


"Why?" is the question that is always on the mind of the curious boiler inspector.

The inspector, whether from the jurisdiction, insurance company or the operator/maintainer, must always ask this question. The inspector's job is not finished when corrective action is recommended to correct an obvious problem discovered during an inspection; there is more. The inspector must ask, "Why did this happen?"

Review the following hypothetical situation as an example.

An inspector discovers cracks in the fireside of a mud-leg in a firebox-type steam boiler and recommends a repair by welding. In this case, if the question, "Why did the plate crack?" is not asked, only the symptom is corrected and the cause of the problem is not detected. If the question is asked, further investigation may reveal that the mud-legs are packed with scale, insulating the plate from boiler water. Of course it would be required that the boiler be cleaned of scale before the weld repairs are made.

If a second question, "Why is there scale?" is not addressed, then another symptom would be corrected without affecting the root of the problem. When the cause of the scaling is investigated, it would most likely be discovered that the boiler is using excessive make-up water. Again, why? After pressing further, the investigation reveals that the condensate return pipe is leaking. It would be recommended that the leaking pipe be replaced.

The investigation continues, only to uncover that the pipe leaked because of internal corrosion. It is now recommended that the services of a water treatment specialist be acquired. The specialist determines the boiler water requires treatment not only for preventing scale in the boiler, but also treatment of the condensate and pre-boilers systems to inhibit corrosion.

The inspector recommends that the boiler water treatment program be closely monitored and adjusted as necessary.

If the inspector had stopped asking, "Why?" at any point during the investigation, only the symptoms would have been corrected and the problems would be recurring.

Inspections routinely evolve into investigations with symptoms of a problem providing the clues to the inspector. Only by asking, "Why?" at each step of the investigation will the inspector identify the root cause of the problem and be able to recommend the proper and complete corrective action.


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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