Fuel and Combustion Systems Safety: What you don't know can kill you!

Preface

I wrote this book with the intention of passing along what I have learned in 30 years of working in the field of industrial fuels and combustion equipment. I had never thought of myself as an author or an academic – I was always focused on just trying to be a good engineer. I am and have always been very passionate about being an engineer. I believe with my heart and soul that it is truly a profession where one person can change the entire world. I still tell this enthusiastically to young people today. I thank God that my mother encouraged me to follow in the footsteps of my brother in law Michael Novak who got his electrical engineering degree at Youngstown State University in the 1960's. I too would end up there after graduating from high school in Youngstown, Ohio in 1976 to earn my degree in Mechanical Engineering in 1981.

In 1985, at the tender age of 27, I started my own business as a one-man part-time operation working from my home doing mechanical engineering work for industrial clients. I did this while I pursued my MBA from the Weatherhead School of Management at Case Western Reserve University in Cleveland, Ohio. My first client was my previous employer SOHIO where I worked as a corporate Energy Systems Engineer doing boiler- and steam-related projects at refineries and chemical plants. You might know the company better as John D. Rockefellers place, Standard Oil of Ohio. What a fantastic place to start a career! I appreciate my early mentors William Bill Frink and Ralph Ender who shaped my early views of how to conduct oneself as a young engineer. I will never forget Bill interviewing me and asking how I picked YSU as a college. I was really taken back by the question because in my world, being the son of first generation immigrants with my father being disabled for my entire life, mom working full time, and me paying for my own school I had never actually known there was a choice.

I was excited about a career where the things that I worked with were on a surreal scale. The boilers and furnaces were multiple stories and the energy release was on a massive scale. It was awe inspiring to just be near such equipment let alone to actually be part of improving it. The dark side of the size and scale of this equipment was what I also witnessed when things went wrong. I was moved by the size and scale of disasters where I witnessed the aftermath. When I saw the pain and devastation of these disasters my way to personally change the world as an engineer was to focus my little business on creating systems to make sure these kinds of disasters would never happen again.

The company I founded and nurtured for over 28 years, CEC Combustion Safety, inspected and tested thousands of fuel trains at over 500 plant sites in dozens of countries. We trained tens of thousands of people in how to recognize fuels and combustion systems hazards and how to operate and maintain this equipment safely. This was done with a very unique and rigorous protocol that embodied applicable codes and lessons learned. This work has been and is today being done for the world's most widely known and successful companies, including U.S. Steel, Ford Motor Co., General Motors, ConAgra, Tyson Foods, Pfizer, Owens Corning, Alcoa and dozens of others throughout the world. Although I am no longer associated with the firm, (selling it in 2011 to Eclipse Inc.), Lach and Doug Perks, owners of Eclipse, a worldwide leader in combustion systems and burner technologies, are continuing to pursue the company's core safety message.

I am proud of what was accomplished from an idea and the difference the dedicated staff has made in the lives of many throughout the years. After witnessing deaths, horrible injuries, personal tragedies, lawsuits, plant closings, and the blanket destruction of lives, my former staff and I had dedicated ourselves to doing our part to prevent these things from ever happening again. This one desire, to help people with our knowledge and skills, drove us all every day. There's nothing else that can motivate the dozens of staff to have given up time with their families to be on the road 5 days a week for years in hot boiler rooms and industrial plants all over the world. I cannot name them all but my most sincere thanks go out to every CEC employee through the years. I know they got their motivation daily in the eyes of everyone they helped when they left every plant and gave operating staff peace of mind.

My boys, John and Zack once asked me, Dad, so what is life all about? Is it just that we work every day and have a family and that's it? I told them that at the end of the day you need to leave the world a better place than you found it. Find something to do that will be your legacy that improves society as a whole. Leave your mark. And so I say to you reading this book, if you can apply even some of the most basic knowledge you find here and prevent even one minor incident, you will have helped to make my life even more worth living. I hope that this book in some small way contributes to the greater good, and I thank God for the opportunity that He has given me to put it together.

I have dedicated this book to the thousands of people who have been injured or have lost their lives in tragic fuel or combustion equipment-related incidents. This book contains over 50 stories and real-life incidents to provide practical learning experiences. These incidents resulted in 46 deaths, hundreds of serious injuries, and billions of dollars in economic losses. It is not an attempt to scare you, nor is it an attempt to point fingers. The stories you will read are meant to help you understand that bad things can happen to anyone operating fuel systems and combustion equipment if the proper (PPE) people, policies, and equipment countermeasures are not in place.

The stories that are presented in this book are not extreme or rare cases. For every incident that results in injury or death, there are dozens of incidents you do not hear about. With this type of work, if just a few things do not go your way, you too can be part of another tragedy. Your best defense is knowledge: knowing about fuels, piping, combustion, controls, and risks. This book is just a start. As you read on, I hope you will see that ensuring fuel systems and combustion equipment safety is an ongoing process and journey, one that takes real time, effort and teamwork in order to be successful.

I owe a great debt to many friends and colleagues in industry and elsewhere who have supplied the information and ideas that are discussed in this book. I especially want to thank the people at Ford Motor Company and the United Auto Workers and the members of their fuel-fired combustion equipment safety program. When I look back on my life, being able to work with these fine people in the aftermath of an incident there I realize it changed me forever. Some of these people included Scott Bell, Danny Berry, Dwayne Atkins, Hank Budesky, Bob Konicki, Don Schmid, Chris Petersen, Dr. Greg Stone, and many others. We worked together for more than 10 years almost weekly to develop programs that I am confident are the best in the world.

Others who have contributed greatly to this book include Bryan Baesel of CEC Combustion Safety Inc., who worked with me proofreading manuscripts and helping to suggest information that would improve this book. Other who have been influential in my journey include Joel Amato State of Minnesota Boiler Chief, David Douin Executive Director National Board of Boiler and Pressure Vessel Inspectors, Dave Peterson, Loss Engineer Cincinnati Insurance, Al Sobol Combustion Engineer, Walt Luker former President of Matrix Risk Consultants, and Steve Mezsaros of Pfizer were all friends and colleagues that contributed greatly throughout my career. I also want to thank my friend Sean George whose life was changed by a personal tragedy related to this topic. Instead of leaving the world he spent his life advocating for things that would help avoid others from experiencing what he went through.

Other organizations that helped with the book and that continue to contribute daily to the body of work related to fuels and combustion equipment safety are the U.S. Chemical Safety Board, the National Fire Protection Association, the American Society of Mechanical Engineers, and the National Board of Boiler and Pressure Vessel Inspectors. I interfaced with Dan Tillema from the U.S. Chemical safety board on a number of occasions. He has helped me to locate several sources of information and has been unwavering in his support for anything that can improve safety. John Bresland former Chairman of the U.S. Chemical Safety Board provided a foreword for the book and has also been an inspiration. NFPA, ASME, and NBBI have responded enthusiastically for the many requests I have made for materials and extracts to be used in this book. They have also published many of my articles through the years and have accepted me as a speaker at dozens of conferences.

Richard Hoffmann, a metallurgist provided assistance in the materials area, and his contributions are appreciated. Ted Lemoff, recently retired from NFPA has been a longtime friend and contributor to everything about fuels and combustion safety. He assisted me in finalizing the book and made contributions in the fuel gas and purging areas, and with the artwork. Ted is truly a competent, caring and very special person I am lucky to be able to call a friend. The following members of the NFPA Technical Committee on Ovens and Furnaces reviewed and improved parts of the book related to their expertise; Franklin Switzer of S-Safe, Tom George of Tokio Marine Insurance, and Ted Jablkowski of Fives North American Combustion Inc. Also, Tom Witte contributed to the information on nitrogen for purging.

Thank you also to the following who provided photos and drawings that make sometimes difficult concepts easier to understand to many readers; Tony McErlean of Air Products; Jim Griffin of Emerson Process Management; Stephanie Taylor of Dwyer Instruments; Chad W. Bryan, Chief Boiler Inspector, Tennessee Department of Labor & Workforce Development; George Nichols Technical Illustrator, John Finn, FEBA Technologies; Robert Ratkus, DCP Midstream; and Paul Wehnert, Heath Consultants.

I hope that this book inspires you to truly change the culture at your organization and introduce these important topics as a means to enhance the overall safety. I hope you are not picking this up after a tragedy. If you are, then it is not too late to avoid another one. If your site or sites have not had issues, consider yourself lucky. Do not wait until it is too late, start now and start the journey to address People, Policies, and Equipment in this fuels and combustion systems world.

Last but certainly not least, my special thanks also go to the love of my life, Lisa Roe. I remember turning to her in 2009 and saying from the basement of our home, Hey, today I am starting this book thing. That launched literally a couple thousand hours of work and her being patient with me and supportive through all the toil.

John R. Puskar

Foreword

During my tenure as a board member and chairman at the United States Chemical Safety Board (CSB) from 2002 to 2012, the CSB investigated several incidents involving releases and explosions of flammable gases. Earlier, while I was an executive at Honeywell, for several years I had responsibility for the operation of three natural-gas-fired boilers. Both of these professional experiences have reinforced to me how critically important it is to understand the hazards of flammable gases and to be certain that all appropriate safety precautions are taken whenever anyone is working with and around flammable gases.

Here are three examples of what can happen if such safeguards are not taken:

In Connecticut, a major gas-fired electric power generating facility was under construction and within a few weeks of starting up. To clean their newly installed gas inlet lines, workers blew natural gas through the lines at high pressure, venting the gas to the atmosphere. Unfortunately, the gas came in contact with an ignition source and exploded. Six workers were killed and the explosion caused catastrophic damage to the almost-completed facility. Following its investigation, the CSB recommended that natural gas be banned as a cleaning agent for utility piping.

In West Virginia, a propane explosion occurred at a convenience store when a 500-gallon propane tank was being taken out of service so that it could be replaced with a new tank. During the tank switchover, propane leaked from a valve on the older tank. Emergency crews were called but the convenience store was not evacuated. The propane seeped into the store, found an ignition source, and exploded. Two emergency responders and two propane technicians were killed, the convenience store was demolished, and workers in the convenience store were injured. All of this could have been avoided if the area had been evacuated when the propane leak was first detected.

In Garner, North Carolina, a new industrial water heater was being installed in a meat factory. It was to be heated with natural gas. A newly installed natural gas line was being purged to remove air from the line. The purging agent was natural gas and it was directed into an enclosed room in the factory. The concentration of natural gas built up in the room, contacted an ignition source, and exploded. Four workers died and dozens of other were injured in the collapse of sections of the factory. Upon completion of its investigation, the CSB recommended that when facilities are purging gas piping, the purged gas should be directed to a safe location outdoors.

Each of these terrible accidents could have been avoided by applying common sense prevention techniques: don't clean process lines with high pressure natural gas, use a safer alternative; know the appropriate safety precautions when you are working with propane tanks and evacuate to a safe distance at the first sign of a leak; don't vent a natural gas line into an enclosed space.

More generally, how do companies prevent catastrophic accidents that kill and injure employees, destroy facilities, and cause untold damage to finances and reputations? There are no simple answers but here are some practical suggestions: provide active leadership on process safety at all levels of the company, hire and educate the right people, understand and control your hazards, focus on both personal safety and process safety, develop and analyze process-safety metrics.

In short, companies need to understand the hazards in their operations and take the necessary steps to control those hazards.

If your industry's hazards include the use of combustible gases, John Puskar's book will point you in the correct direction. John has spent many years in the business of helping clients and companies understand and deal with flammable gases in their facilities. He has 30 years of experience dealing with combustion systems and he is a well-known and respected expert in the investigation of combustion incidents like the ones described above. We are very fortunate that he has taken the time to put his knowledge and expertise into writing. This book will be a very valuable asset for industry professionals.

In particular, John's book should be read by anyone involved in the natural gas business, whether as a producer or as a consumer. There is no room for complacency in dealing with flammable gases. It is especially important that company executives read some of the fifty case histories in the text. They need to understand what the hazards and risks are in dealing with this very important energy source. Quoting Carolynn Merrit, the late chair of the Chemical Safety Board: If you think safety is expensive, try having an accident.

John Bresland

Shepherdstown, West Virginia

May 2013

1

What You Don't Know Can Kill You

How the Book is Structured and What This Chapter is About

Most chapters in this book begin with a small introduction and then a story that provides the flavor of an experience related to the topics in that chapter. These stories introduce real concepts that under certain conditions can lead to devastation.

The book also features a number of emphasis boxes that give key concepts special attention. In many cases the boxes describe seemingly obvious and simple, but nonetheless vital, issues. In this chapter we give you a flavor of some high-level concepts involved in the fuels and combustion systems safety world. We form a basis for an understanding of the more technical issues presented in later chapters.

There's something in this book for everyone: from operators of equipment and hands-on maintenance personnel to corporate risk managers and global safety directors. The book's perspective switches frequently and addresses issues of concern for all these groups. This chapter will mean more to corporate staff, managers, and those in charge of fuel and combustion equipment safety and risk management programs. It is my hope that many of you will read the chapter and realize the importance of this topic. This will give you the perspective to be supportive of, and wanting to implement, the concepts and strategies presented in subsequent chapters.

Real-Life Story 1: Innocent Lives Lost from a Hot Water Heater Explosion

A lot can be learned from reviewing a terrible disaster that left five children and one teacher dead at an elementary school in Spencer, Oklahoma, in 1982.¹ A hot water heater explosion changed the town, and many families, forever. Shedding light on the underlying causes behind the explosion at Star Spencer Elementary School provides an opportunity to review your own combustion equipment testing, repair, and preventive maintenance schedules and to reframe your thinking about which of your combustion systems may be important.

It was shortly after noon in a busy school cafeteria on an average day. Children were seated at tables enjoying lunch when their secure little world was torn from them. Suddenly, a concrete wall that separated the lunchroom from the kitchen blew in as an 80-gallon water heater exploded and launched itself skyward. The children seated nearest the wall were crushed and killed as concrete and steel were propelled from the epicenter of the blast. In all, seven people died and 36 were injured.

Tragic warning signs at Star Spencer screamed out loudly to those trained to listen. Sadly, most building managers and facility staff would never have heard them. For example, would you know that when people complain that the water is too hot in the sinks, it could be a sign that you are about to have an explosion in your building? What about that safety relief valve that keeps dripping, or the little gas leak? It was a combination of issues as subtle as these that contributed to the deaths and injuries that day.

The first employees arrived at the school at 7:00 A.M. The cafeteria workers noticed that the domestic hot water was much hotter than normal. The custodian was called, and the gas water heater was shut down to await the arrival of a maintenance technician. The technician's fix was to replace the gas valve and relight the water heater. He replaced the valve with the only valve immediately available, a used valve that had been sitting on the shelf in the maintenance shop. The technician returned within the hour and noted that the water heater seemed to be working normally.

The cafeteria workers soon noticed that the water temperature was again much too hot, and getting hotter. They placed another call for service, which tragically went unanswered. At 12:13 P.M., the explosion ripped through the school.

Investigators found that the hot water heater's burner would not shut off. The used replacement gas valve was defective. These have been the subject of safety recalls. It is recommended that you check the Consumer Products Safety Commission website (www.cpsc.gov) to see if you might have one of these at your facility or even at home.

Hot water heaters are also required to have safety relief valves, which are supposed to relieve water if an excess temperature or pressure condition occurs. The safety relief valve on the water heater was found to be altered and could not function as designed. Someone had cut off the temperature probe part of the device, rendering this part of the protection ineffective.

Because the water had no place to go, it continued to increase in temperature and pressure as the heater continued to fire and store the energy input. At some point the limits of the strength of the steel and its connections were reached and the tank tore itself apart. At failure, when the tank gave way, all the water inside expanded at 1600 times its volume in an instant. This created a pressure pulse that blew out walls and moved anything in its path, sending debris flying in all directions.

Had the proper procedures and inspections been put in place, this accident could have been prevented. If there was a preventive maintenance schedule in this case, it was ineffective. The safety relief valve was installed incorrectly, the high-temperature-limit shutoff did not function, and the gas valve was defective. These problems were all avoidable.

Oklahoma's boiler inspection law at the time covered high-pressure steam boilers but not smaller equipment such as water heaters. This situation was not unique to Oklahoma. Most states do not provide much in the way of inspections for certain classes of combustion equipment, even in educational facilities or places of public assembly. The school system, then, had to determine what would constitute adequate inspection, maintenance, and repair of the water heater. This is an often-overlooked responsibility. Most facility managers do not understand that they are responsible for proper inspections and maintenance when it comes to fuel systems and combustion equipment. They often think that an insurance or state boiler inspector is providing some overall safety evaluation, but generally this is not the case. In most states, boiler inspection laws call for inspecting only the pressure vessel part of each boiler system, and not for looking at combustion issues.

Boiler inspectors (who are often hired by insurance companies or are employees of the state) have their hands tied when it comes to what they can ask someone to do. They have little enforcement authority. What they are inspecting for is often limited to exactly what is called for by the letter of the law. For example, in many cases they can only evaluate equipment for code compliance based on when it was installed even though important code changes occur almost annually because of advances in knowledge and experience.

Typically, there is no screening for how far away the grandfathered technology is from the most recent codes. This type of inspection sometimes means that archaic and antiquated equipment that has little in the way of modern safety features could technically be in compliance.

Lessons Learned

You as a safety, risk, or maintenance professional and your facilities staff are responsible for all fuel lines, boilers, and hot water heaters, regardless of size and fuel source (even electric). You are responsible even if they are inspected annually by an outside entity and even if there are no local or state requirements to do so. Your guide must be that of standards and codes that exist relative to this equipment. This book gives you a chance to discover these requirements and apply them to your facilities and equipment before an incident occurs and lawyers tell you that you should have been fulfilling these requirements. Ignorance is not a defense.

Equipment does not have to be massive in size or Btu capacity to cause death and destruction. I began the chapter with this story to bring the reality of this type of small often overlooked equipment directly into view. It is my hope that at some point someone will go down to their basement and change out a safety relief valve or locate a problem on a hot water heater that will save a life.

The energy that can be stored in water is incredible. Check out the popular television show Mythbusters's video of blowing up a water heater² to see what can happen. This video shows a water heater launching through a simulated house roof hundreds of feet into the air when the tank ruptures. You must, on a regular basis, review these often ignored pieces of equipment and replace the safety relief valves. This is an inexpensive task that is simple to do. If you review the manufacturers' instructions for most small relief valves, you will see that they call for regular inspections. In most cases this inspection is supposed to include their removal to look inside. Rather, given their cost, you might as well replace them. Be careful lift-testing these; I have often found that they do not reseat effectively. Again, replacement on a schedule is your best option, whether or not they need to be serviced. Also make sure that the burners on hot water heaters are evaluated periodically. Their flames need to be reviewed to see that they are burning cleanly, and drafts need to be checked. It is also important to ensure that over-temperature shutoff safety devices are functional.

1.1 Knowledge Gaps in Operating Fuel Systems and Combustion Equipment

Even though humankind has used fire for millions of years, a continuing pattern of accidents, deaths, and injuries tells us that there is still a long way to go when it comes to fuel systems and combustion equipment safety. You just read a story about how a simple hot water heater in a school cost six lives because of seemingly simple issues. And this equipment was not nearly as large or complex as that at most industrial sites.

My 30 years in the business has shown me that many incidents happen because personnel at industrial sites are often not trained adequately in the safe startup and shutdown of combustion equipment, daily operations, or proper testing of safety devices and maintenance of critical systems. Very few formal classes exist regarding burners, gas piping, safety systems, or fuel/air ratio controls. The fuel and combustion equipment industry itself is very fragmented. Although there are numerous technical books and articles on the subject and codes and standards provide safety information, much of the knowledge in use seems to be tribal, passed on from person to person from word of mouth among those who operate and maintain combustion equipment. Much of this information is wrong and misinterpreted.

To be sure, most companies attempt to maintain their equipment. However, the maintenance is usually done by someone with little formal training, and equipment is often far removed from its optimum configuration after years of being cobbled together so as to just run. Over the years, while inspecting thousands of pieces of equipment, I've experienced my share of horror stories—and not just the kind that end in explosions. I've witnessed alarms ignored and safety devices turned off. I've even seen wooden sticks and cardboard shoved into relays and safety devices to keep the safety interlocks from shutting equipment down—a potentially deadly fix.

There seem to be two worlds out there: one where large organizations have enough of this equipment to have very good staff members and practices and another where there are just a few pieces of this equipment and no one with much knowledge of it. The more common situation is that fuel systems and combustion equipment are some small ancillary part of the operation and no one is really fully trained or completely understands the equipment or the hazards. Many of the tragedies related to fuels and combustion equipment throughout history could have been prevented with the right PPE. In this case I'm not referring to personal protective equipment but to people, policies, and equipment. In my opinion, every fuel or combustion equipment incident begins as a people, policy, or equipment issue. My goal is to provide you with knowledge of these PPE tools that will dramatically reduce the risks of an incident.

From my contacts in industries that use fuels and combustion equipment, I have found that most owners of fuel-fired equipment do not understand the obligations that they have for the safety of their workers and plants. Many professionals responsible for facilities with fuel-fired equipment work within a culture of ignorance, misunderstandings, or denial about the impact of an explosion or fire caused by the operation of this equipment. I am aware of numerous disasters from gas piping or equipment that failed or had not been installed correctly. Many of the real-life stories presented in this book are from my personal experience and witness.

According to the National Fire Protection Association (NFPA), large-loss fires between 2000 and 2009³ (the most recent statistics available at the time of publication) made for losses that averaged $1.1 billion per year during this 10 year period (Table 1.1). Most of these incidents occurred in manufacturing and industrial settings.

Table 1.1 Fires That Caused $10 Million or More in Property Damage, 2000–2009

Furthermore, NFPA reports that U.S. fire departments responded to an estimated annual average of 10,500 structural fires in industrial and manufacturing properties in 2005–2009. These fires caused annual averages of 11 civilian deaths, 254 civilian fire injuries, and $726 million in direct property damage. These types of losses have been experienced in the United States for many years, often resulting from fuel systems and combustion equipment issues that could easily have been prevented. These losses don't count the hundreds of other significant business interruptions, facilities damage, lawsuits, fines, litigation, and lost-market-share issues that have also occurred. Smaller but more frequent production outages also cost millions in business interruptions, supply chain delays, lost orders, and decreased competitiveness. These losses are often deemed to be culturally accepted as a general cost of doing business. It doesn't have to be this way.

Fuel systems and combustion equipment safety is critical to the daily operation of many facilities and their employees. Unfortunately, many companies act only when a very large and tragic event occurs. Many companies believe that explosions, fires, or outages from fuel-fired equipment only happen to others—that their company is immune. Only loss of life seems to make the 11 o'clock news. Headlines soon fade or rarely get the follow-up attention required to highlight the pitfalls of equipment that has been poorly maintained and operated. Today's corporate public relations departments are also very good at shutting down the flow of information that may leak to the media. My experience has been that little poofs,pops, bulging furnace walls, and pregnant boilers are more prevalent than not and imply that incident headlines are only the tip of the iceberg. For each incident reported there are undoubtedly many left unreported because they did not result in death, injury, or significant loss of production. Hence, they are never clearly researched and the lessons are not adequately learned.

1.2 Managing Fuel Systems and Combustion Equipment Risks

OK, so by now you accept that there is risk and possibly danger associated with fuel systems and combustion equipment. If you wanted to better understand how that applies specifically to your facilities and equipment, how would you know what safe is? In the fuel and combustion systems world, safe is not necessarily a destination but a journey. The state of the art is constantly evolving in the codes and standards world. These are documents and sources of information that are out there to help you better understand what level of safety your organization is at and the type of journey you should be considering. Many proactive corporations manage their fuel and combustion system risks successfully by creating programs that address people, policy, and equipment issues. They spend millions of dollars to develop, implement, and update ongoing programs.

The journey will also depend somewhat on your organization's culture. Culture can be described as the subconscious knowledge that is embedded in people without them even knowing. Culture is slowly absorbed through habits and regular reinforcement. It becomes the emotional guiding light in the presence of confusion, stress, and dangerous situations. It's what's there when subconscious thought must take over because things are happening too fast. Combustion equipment culture is no different.

In some organizations the culture is such that there are willing and eager minds open to learning. Information is shared openly and there is little fear of retribution for making honest mistakes. These can be characterized as rapid acceptance cultures. In other cases, where someone will be harmed if even a slight mistake is perceived, acceptance and new thinking will be difficult. The following story demonstrates how culture might influence your experience in managing these risks.

Real-Life Story 2: The Bulge in the Boiler Firebox

I walked into the boiler room, took one look down the side of the boiler, and said to the boiler operator on duty: Excuse me, can you tell me anything about what happened here in the past to make that bulge? When looking down the side of what used to be a flat surface, it was clear that the side of the boiler bulged outward. Obviously, sometime in the past there was an explosion. It's not clear that anyone reported it. It's also not clear that there was damage beyond the outer boiler skin being deformed, but then how would anyone know? Remember, sometimes staff, even those who might be managing the boiler house facilities, might not want to report something like this and attract a lot of scrutiny. The culture may be that it's not a good career move for anyone to do so. When you review facilities, make sure to ask about anything you see, even if it's old or very obvious, as it may be the first time that it has really been brought to anyone's attention and been acted on.

The operator responded: Oh, that, that was a small poof we had. It just happened once at light-off but it went away. It was clear that this investigation now needed to focus on a few key issues, such as low-fire gas flow control valve positioning for light-off, malfunctioning gas pressure regulators, the possibility of leaking valves, faulty purge timing, and incorrect fuel/air ratios.

The investigation was begun using a combustion analyzer to check the flue products. This identified an excess of 1500 ppm carbon monoxide (CO) at a low fire level. The maximum CO expected for a well-tuned burner of this type for this application should have been less than 100 ppm. It got worse as the boiler moved off low fire and pegged the meter at over 2000 ppm CO. Significant levels of CO are an indicator of poor fuel/air mixing and incomplete combustion. No one could remember reviewing or adjusting the fuel/air ratio since the boiler was installed and commissioned over 10 years ago.

Many combustion analyzers can only read CO to about 2000 ppm. The generally accepted lower flammable limit of carbon monoxide is 12,500 ppm,⁴ or 12.5%. It would be rare to have an explosion due to accumulating this much CO. However, because CO can be read by an analyzer, it serves as a surrogate indicator of other additional combustibles present, including unburned fuels. Partially burned fuels represent things that come from the cracking of some of the hydrocarbon molecules when they are partially burned. The elevated temperatures and mixtures of fuels and fuel derivatives can have a wide range of ignition temperatures. It's these other combinations of things, not the CO, that usually end up being what ignites and makes for explosions.

Lessons Learned

Cultures must be such that personnel are not afraid to report issues. An unreported minor issue can easily degrade quickly and cost someone his or her life. Always question any damage you see to a firebox or fuel train. Never assume that since it looks old, everyone is aware of what happened and that the actual cause has been identified and the problem abated properly. Best-practice organizations conduct daily flame observations and logging of findings. They also conduct fuel/air ratio adjustments (burner tuning) at least annually.

Incomplete combustion can make for flammable mixtures in the firebox and flue passages of combustion equipment. If flue gas oxygen metering and reporting are part of the equipment instrumentation, be aware of the limitations of meters being used, exactly what they measure, and all of the implications of the meter readings. Train the staff and drill them about what levels of oxygen should be a cause for concern and what actions should be taken.

1.3 The Creation of Fuel Systems and Combustion Equipment Codes and Standards

Because of numerous tragedies and the continuing human desire to use heat processes to advance society, many smart people have gotten together over the years to learn from past mistakes and to create definitions and examples of what safe fuel and combustion systems should look like. Some of the most important of these documents are called codes and standards. Today's many codes and standards organizations consist primarily of volunteer experts working under well-defined protocols to assemble informative documents that include much hard-learned wisdom. It's your challenge to read and incorporate the knowledge and experiences contained in the applicable standards and codes and apply this information to enhance the level of fuel and combustion equipment safety within your organization.

To learn why these documents and organizations came into existence let's look at the history of combustion equipment in industry. During the nineteenth century, boilers and steam engines became the heart and soul of the industrial revolution. At the same time, accidents related to boilers and pressure vessels became commonplace. From 1870 to 1910 there were more than 10,000 recorded boiler explosions in North America⁵ (an average of 250 per year). By 1901, the rate had climbed to between 1300 and 1400 recorded boiler explosions per year. When these incidents occurred, they were often horrific and involved many people. There were public outcries for remedial action. It soon became clear that this technology needed to be made safer if it was to proliferate. The American Society of Mechanical Engineers (ASME), answered the call with groups of volunteer mechanical engineers coming together to create the first boiler code committee in 1911.⁶ The first ASME boiler code was published in 1914–1915. The code documents produced by ASME identified safe practices for the construction of boilers and pressure vessels and for pressure piping systems. These documents provided specifications for steels required, their thicknesses, welding practices, and many other fabrication and installation issues that enhance safety. ASME codes, standards, and more information about the group may be found at www.asme.org.

Once these documents were developed, industry experts realized that there needed to be another group that actually enforced the rules. This group would need to consist of paid professionals who could be on the job every day acting as code enforcers or inspectors. They would need to visit fabrication shops, review welds, and measure and verify thicknesses of pipes when boilers were being fabricated. Identifying this need gave birth to the National Board of Boiler and Pressure Vessel Inspectors (NBBI) in 1919.⁷ Headquartered in Columbus, Ohio, this group was created to promote greater safety to life and property through uniformity in the construction, installation, repair, maintenance, and inspection of pressure equipment, most of it boilers.

The National Board membership oversees adherence to laws, rules, and regulations relating to boilers and pressure vessels. The National Board members are chief boiler inspectors, representing most states and all provinces in North America, as well as many major cities in the United States. More information about the NBBI is available at www.nationalboard.org.

NBBI functions include the following:

Promoting safety and educating the public and government officials on the need for manufacturing, maintenance, and repair standards.

Offering comprehensive training programs in the form of continuing education for both inspectors and pressure equipment professionals.

Enabling a qualified inspection process by commissioning inspectors through a comprehensive examination administered by the National Board.

Setting worldwide industry standards for pressure relief devices and other appurtenances through operation of an international pressure relief testing laboratory.

Providing a repository of manufacturers' data reports through a registration process.

Accrediting qualified repair and alteration companies, in-service authorized inspection agencies, and owner–user inspection organizations.

Investigating pressure equipment accidents and issues involving code compliance.

Developing installation, inspection, repair, and alteration standards (the National Board Inspection Code).

As additional emphasis was put on having safe standards for the use of fuels such as natural gas, which led to a group called the National Fire Protection Association (NFPA) being created.⁸ The organization was formed by a group of sprinkler manufacturers, installers, insurance, and enforcement officials, who developed the first code for the installation of fire sprinklers, issued in 1896. NFPA's mission is to reduce the worldwide burden of fire and other hazards on the quality of life by providing and advocating consensus codes and standards, research, training, and education. NFPA publishes more than 300 codes and standards. Among them are codes and standards regarding the safe design and installation of fuel train controls and combustion systems. These include specific codes and standards for boilers and for devices other than boilers. The NFPA's website is www.nfpa.org.

Before describing some of the codes and standards developed by these organizations and others, it's important that you understand the difference between a standard and a code. A standard is prepared and presented by a recognized national organization that collaborates on technical issues and identifies state-of-the-art best practices for safety. A code, on the other hand, is intended to be adopted as a law. Standards usually say how to do something for safety, whereas codes require when and where to do something for safety.

Each code and standard is managed by a combination of staff and dedicated volunteer committees with members from among end users, insurance companies, manufacturers, testing laboratories, special experts, and trade associations. These groups usually meet several times a year and are responsible for maintaining, updating, and eventually gaining consensus