Skip to content

Safety Moment #63: Happy Motoring

Happy Motoring and the Hubbert Curve

There is no shortage of written material to do with technical topics, including process safety management. But only a tiny number of papers or articles establish a place for themselves in history. Virtually all that we read or write is evolutionary rather than revolutionary.

There are a few exceptions to this generalization. Occasionally someone writes a paper or article that changes the way in which we view the world. And one of those seminal publications was, in my opinion, a paper published in the year 1956 by Dr. M. King Hubbert of Shell Oil.

One may reasonably ask how a paper that was written over 60 years ago can affect our lives now. Indeed, in the short-term Hubbert’s paper is not going to change the manner in which we design and operate process facilities. But in the medium to long-term — say within the next 25 years — his insights will, I believe, have a dramatic impact on all aspects of life, including the energy and process industries.

Nuclear Energy and the Fossil Fuels

M. King Hubbert (1903-1989)M. King Hubbert (1903-1989)

The word “genius” is bandied about all too frequently. But one man who could well qualify for the term is M. King Hubbert  Not only did he come up with extraordinary insights to do with the end of the oil age, he did it in a time of “Happy Motoring” when what he was talking about seemed to be unbelievable. And he had the courage of his convictions — he talked about these issues against the will of his employer (Shell Oil), and he continued to speak out until the end of his life.

Of Dr. Hubbert’s publications, probably the most important was the paper Nuclear Energy and the Fossil Fuels presented at an API (American Petroleum Institute) conference in San Antonio, Texas in March 1956. At the time he was a Chief Consultant (General Geology) with the Shell Oil company. (In other words, he was an authoritative figure working for a major oil company speaking at an API conference — he was not some fringe oddball. He was very much mainstream. )

As its title suggests, the paper has two major sections. The first section is to do with fossil fuels — specifically conventional oil in the United States. The second section is to do with his predictions regarding a transition to nuclear energy. In this Safety Moment I will focus on the fossil fuels section of the paper. We can discuss his thoughts to do with nuclear power in a later Safety Moment.

Put a Tiger in Your Tank

Put a tiger in your tank

1956 was a long time ago — a time that seems rather innocent now. It was the age of ‘Happy Motoring’. The oil fields of Texas were producing at full throttle and new sources of oil, particularly in the Kingdom of Saudi Arabia, were coming into play. Limits — what limits?

Socially, the world was much different from ours. For example, as Hubbert was presenting his paper it is probable that at least half the people in the room would have been smoking. And look closely at the ‘Happy Motoring’ advertisements. The people in the cars are not wearing seat belts, and their cars are being refueled by a uniformed attendant — no self-service in those days).

More fundamentally, we in our time are sensitized to issues such as climate change and resource constraints. These issues were only on the horizon in 1956.

Humble Oil glacier melting

These are the reasons I give for stressing Hubbert’s courage. It was as if he was speaking a foreign language to the people of his time. (The Shell Oil company attempted, at the last minute, to stop him giving the paper. But he went ahead anyway.)

The Hubbert Curve

In his paper Hubbert presented a curve showing the production rate of conventional oil in the United States. It is reproduced below. (It is important to understand that Hubbert was focused not on the amount of oil being produced, but on the number of discoveries that were being made. In other words, he wanted to know if future production could adequately replace current production.)

The Hubbert Curve
The Hubbert Curve

This model provided the technical basis for what later became known as “Peak Oil”.

His basic idea was that the discovery and exploitation of oil follows a pattern on the following lines:

  1. The initial discoveries are made.
  2. Further exploration in the same area finds more oil.
  3. Production of oil from that area increases rapidly.
  4. Eventually production reaches a peak as the number of new discoveries declines.

The graph (hand drawn, these are the days before personal computers) shows the production of petroleum in the United States starting around the year 1900. There is a steady rise (with a dip due to the depression of the 1930s) up until 1956 — the year of publication of his paper.

Hubbert then projects future production rates. He shows oil production from conventional wells in the United States peaking around the year 1970, and then steadily, but irrevocably, declining. (He anticipated that the total quantity of oil production in his estimate was on the low side, as indeed it was. He was looking at timing.)

It was this forecast that made the paper so controversial. Nevertheless, he was remarkably prescient. The production of land-based conventional oil did, in fact, peak at the time he forecast it to do so.

Although Hubbert’s paper was focused on the production of conventional oil in the United States, his basic idea was rapidly adopted to the production of oil world-wide, and then to the discovery and exploitation of other natural resources.

Offshore and Tight Oil

Although Hubbert’s forecast to do with the timing of the production of conventional oil in the United States was accurate, he did not consider new sources of oil, particularly the huge wells in the Gulf of Mexico, and tight oil. Hence the total production of oil from all sources in the United States has not declined as fast as the production from just conventional fields.

Does this mean that Peak Oil has gone away for ever? Can we assume that we will continue to find new sources of oil ad infinitum? We so easily fall into the trap of straight line thinking — the future, we so blithely assume, will simply be a continuation of the present.

Well, maybe. Our world is very different from the world of 1956. Can we be so sure that the world a generation from now will look just like ours?

Safety Moment #63: Happy Motoring

Copyright © Ian Sutton. 2018. All Rights Reserved.

Safety Moment #64: Hydrocarbon Storage Tank Spacing

Tank Farm Spacing


The material in this safety moment is taken from the book Plant Design and Operations and from the ebook Siting and Layout. Further discussion to do with layout and spacing issues is provided in the article Siting and Layout of Process Facilities.

In Safety Moment #57: Equipment Spacing (Pumps/Fireproofed Pipe Racks) we started a discussion to do with the layout of equipment in a process or energy facility. In it we noted that there are many codes and standards that cover this topic. To supplement those codes we provided some guidance regarding the layout of pumps, given that they are a source of high pressure leaks.

Continuing the discussion in Safety Moment #64: Hydrocarbon Storage Tank Spacing, we look at hydrocarbon storage tanks, sometimes known as “API Tanks”. The following general guidance is provided.

  • Tanks should be located at a lower elevation than process areas so that if one of the tanks leaks and the secondary containment is not effective, flammable and toxic materials will not flow into the process areas. (The same argument holds if the spilled liquid could create a vapor that is denser than air and that could then flow downhill).
  • For the same reason tanks should not be located above populated areas.
  • Where it is not feasible to locate tank farms at elevations lower than process areas, increased protection measures may be required to offset the increased potential for ignition. These measures may include:
    • Diversion diking
    • High-capacity drainage systems
    • Vapor detection placed near potential release points
    • Increased fire protection
  • Spacing between tanks should be great enough to contain a fire, prevent spread of the fire to other tanks, and to allow sufficient access for firefighting crews.
  • Equipment other than associated piping should not be located within the diked area of storage vessels.
  • Flammable gas detection is not usually required for open tank areas unless a potential for gas accumulation has been identified.
  • Toxic gas detection should be installed if the potential exists for gas accumulation in a tank area. Alternatively entry into a bermed area must be treated as a confined space entry.
  • Fire detectors should be provided for tanks containing combustible or flammable liquids.

Secondary containment is frequently installed around tanks and tank farms. It generally consists of a containment or bund wall around equipment or tanks containing large volumes of liquid. If the equipment leaks or the tank is over-filled the liquid is contained and thus prevented from flowing into other parts of the facility, where it could create a safety and environmental problem.

Such a system, which is illustrated in Figure 2.3, is totally passive and therefore inherently safe. It requires neither instrumentation nor human intervention to be effective.

Figure 2.3
Secondary Containment

Tank with bund wall

The general rule is that the secondary containment should have a volume equal or greater to 110% of the volume of the largest tank being protected. If multiple tanks are enclosed, then only a spill from one tank need be considered.

Although a system such as that shown in Figure 2.3 is inherently safe, the drain valve in the wall has to be checked. It is needed because in order to drain accumulated rainwater from the contained area. But, if the valve is left open or if the drain line is broken, say by a passing vehicle or by someone treading on it, then any tank leak will bypass the secondary containment.

Copyright © Ian Sutton. 2018. All Rights Reserved.

Safety Moment #57: Equipment Spacing (Pumps/Fireproofed Pipe Racks)

Pump in process plant

One of the most difficult challenges faced by process safety professionals is that of equipment spacing. On most facilities, especially offshore, space is at a premium and there is a lot of economic pressure to place items close to one another. Doing so not only saves space but reduces the costs to do with long pipe runs.

On existing facilities where the equipment is already in place, a process safety analysis may recommend that additional safeguards, such as an automatic deluge system, be installed if it determined that items are too close to one another.

But, in general, keeping items well away from one another improves safety for the following reasons:

  • A fire is less likely to spread.
  • There is less likelihood of someone injuring themselves during routine operations or maintenance.
  • There is more access space for the emergency response team and their equipment.

There are many regulations, codes and standards to do with equipment spacing and layout. Examples are:

  • API Recommended Practice 752 —Management of Hazards Associated with Location of Process Plant Buildings
  • The National Electrical Code 70; and
  • API Recommended Practice 14J — Design and Hazards Analysis for Offshore Production Facilities.

In addition, many companies have their own standards and guidance.

The use of standards can also be supplemented by vapor dispersion analysis and other types of modeling.

Within this framework of regulations and engineering standards it is useful to have general guidance to do with acceptable spacing. We will be publishing the occasional safety moment on this topic. The first of these is Safety Moment #57: Equipment Spacing (Pumps/Fireproofed Pipe Racks).

Pumps are a frequent source of leaks, and they are often located close to piping, so their location is important.

Air coolers are also included in the Safety Moment because they can draw leaking vapors into their suction and disperse them over a wide area.

Safety Moment #62: From Complicated to Complex

Foggy window representing the uncertainty to do with complex, as distinct from complicated, systems

The material presented here is taken from Safety Moment #62: From Complicated to Complex.

The discipline of process safety management is mature. And, as discussed in posts such as Safety Moment #31: The 26-Year Old HAZOP and Where Then Shall (Process Safety) Wisdom Be Found?, many process safety professionals are looking for new areas in which to apply their skills and knowledge.

In any performance-based program such as process safety, the work is never finished — there is always room for improvement. Nevertheless, the developments that are being made are mostly to do with improving existing programs or techniques. For example, the hazards analysis technique LOPA (Layers of Protection Analysis) has seen widespread application in recent years. Yet it is basically a development of the well-established Fault Tree and Event Tree techniques.

What we have done is to develop a better understanding of complicated systems, and how they can be controlled. Maybe the next line of attack could be to work on complex systems. So, let’s look at the words ‘Complicated’ and ‘Complex’ — words that are often used interchangeably, but which actually have different meanings.

A complicated, but not complex, system

A complicated, but not complex, system


Process facilities consist of thousands of items that are connected to one another and that interact with one another. Yet, in spite of their size they are fundamentally understandable and predictable. For example, if a company builds a gas processing plant that operates successfully, then the owners know that a second plant built to the same design will also operate successfully.

Most process safety work aims to understand and control this complication. The aim is to develop solutions that are both successful and repeatable. For example,

  • Once a method for writing operating procedures has been developed, then that method can be used throughout the organization for writing procedures for all types of facility and activity.
  • Once a hazards analysis team has identified how a pressure vessel may rupture they can apply that insight into the operation of all other pressure vessels.
  • Once an effective technique for analyzing incidents has been developed, that technique can be used for all future incident investigations.

The key words here are ‘understandable’ and ‘repeatable’.

  • A complicated system is predictable; it can be understood by breaking it down into smaller parts, by determining how those parts work and how they interact with one another.
  • A complicated situation can be quantified and understood through the use of metrics.
  • A Command and Control management structure is effective at managing complicated systems.

By and large process safety professionals aim to reduce the risk associated with complicated system. And, on the whole, their efforts have been successful. Process facilities are much more complicated than they were a generation ago — but the complication is understood and it is successfully managed.


A complex system is based on relationships, interconnection and evolution. It is fundamentally unpredictable. (Any system which involves human behavior — particularly the behavior of people in groups — will be complex.)

Complex systems do not have to be complicated — although most are.

Key aspects of a complex situation include the following.

  • It comprises relationships that cannot be understood just by breaking a system into its component parts.
  • The situation is fluid — surprises happen.
  • ‘Command and Control’ structures will be limited in their effectiveness.
  • It cannot be easily quantified — there are no effective metrics.
  • It will often involve the unpredictable behavior of human beings, both as individuals and in groups.

Climate change is an excellent example of a complex system. The models that have been developed are increasingly accurate at forecasting what the climate will look like in coming years. But factors such as the following cannot be effectively modeled by a computer program.

  • The response by people, both as individuals and as part of larger groups such as nation states.
  • The impact of resource depletion. For example, if oil supplies start to dwindle, will the amount of CO2 being pumped into the atmosphere go down? Or will reduced oil supplies lead to increased coal consumption, thus increasing the amount of CO2 we generate?
  • The impact of increased methane emissions from the tundra.
  • The success or failure of efforts to reduce population growth.

Jevons Paradox

William Stanley Jeavons

William Stanley Jevons

I was prompted to write this Safety Moment after reading Kurt Cobb’s Seawalls for oil refineries and other ironies of climate change adaption. In his post Kurt discusses Jevons Paradox, which is an excellent example of complexity (and also of the Law of Unintended Consequences).

In the 19th  century the economist William Jevons (1835-1882) noted that, as the efficiency with which a resource is used increases, so its consumption goes up.

To what extent this paradox universally applies is a matter of debate (something that is true of all economic issues). But Kurt’s post did prompt me to write to write a response, from which the following is an extract. It is, of course, written somewhat tongue in cheek.

I live in a small town — I can reach most places either by walking or bicycling. This action draws applause from my environmentally concerned friends. But when I point out that the net effect of what I am doing is to increase overall gasoline consumption they simply don’t get it.

I posted an article on this topic about year and a half ago (Jevons Paradox). In it I point out that the dramatic widening of the Katy Freeway (I-10) through Houston has led, paradoxically, to increased traffic congestion. The reason being is that the extra freeway capacity led to the building of new subdivisions in the Katy area. So there are more cars on the road.

I guess it’s a form of Catch 22:

  • If you drive more, or if you drive a larger car, gasoline consumption will increase.
  • If you drive less, or if you drive a smaller car, gasoline consumption will increase.

The essential point is to understand that climate change is a topic of great complexity. Our responses should incorporate an understanding that there are surprises in store for us.

Process Safety Management

So where does this discussion take the discipline of process safety management?

If we are to manage complex situations effectively I suggest that issues such as the following should be considered.

  • Notice new and unexpected emergent directionsNot all events are predictable; we need to adapt appropriately to unexpected situations.
  • Learn from new experiencesLearning, in this context, is quite different from training or from education. It is based on an understanding that unexpected events will happen and the need to figure out why.
  • Factor in the vagaries of human behaviorThose of you who are regular readers of these Safety Moments know that, of all the elements of a process safety management system, the one that I regard as being the most important is Employee Participation. The catch is that people are inherently unpredictable. For example, an Asset Integrity program may be able to predict with a high level of confidence when an equipment item may fail. But no process safety program can predict if and when the workforce will initiate industrial action.

Copyright © Ian Sutton. 2018. All Rights Reserved.

Catalog of Publications from Sutton Technical Books

Catalog of publications from Sutton Technical Books

In addition to our printed books and ebooks from Science Direct we offer the following ebooks and presentation slide packs.

Title Format Price
(U.S. $)
52 Process Safety Moments .pdf 19.50
A Brief History of Process Safety Management .pdf 9.50
PowerPoint Presentations
Presentation: Management of Change — Defining Change .pptx 9.50
Presentation: Operating Procedures — Defining Terms .pptx 9.50


CSB Releases Factual Update on Blowout and Fire at Pryor Trust Gas Well

Pryor Trust Gas Well Blowout

The Chemical Safety Board (CSB) has released information to do with this blowout (

Safety Moment #61: Hard Times for These Times

Hard Times for These Times

We have just released the ebook A Brief History of Process Safety Management.

The first chapter shows how safety became a value within industry. No matter how poor a facility’s safety performance may be, no one ever says, “Safety doesn’t matter”. But this attitude did not always hold true.

In the year 1843 Charles Dickens wrote his book Hard Times for These Times (later shortened to just Hard Times). Using the weapons of satire and irony (weapons in almost complete disuse in the current process safety world) he challenges the industrialists of his time and gives powerful impetus to the idea that safety does matter, that safety is a value.

The following passage is from the first section of the ebook. In this passage Dickens not only raises up safety as being a value, he also challenges the response that “safety is too expensive — we can’t afford it”.


Hard Times for These Times


The historical journey starts in the year 1854 with the publication of the book Hard Times by the famous author Charles Dickens. The book is set in the fictional Coketown. Dickens satirically attacks the industrialists who operate the industries of that town. Of them he says,

They [ the industrialists ] were ruined when they were required to send labouring children to school; they were ruined when inspectors were appointed to look into their works; they were ruined, when such inspectors considered it doubtful whether they were quite justified in chopping people up with their machinery; they were utterly undone, when it was hinted that perhaps they need not always make quite so much smoke . . .

In other words, the industrialists of his time did not treat safety as being a value — and definitely not the top priority.

The weapon that Dickens and his fellow authors used was satire. This weapon has now fallen out of use — modern professional safety workers rarely attempt the use of irony; nor do they write fiction. This is to be regretted.

When faced with the cost of implementing safety programs and standards, the response of industrialists and facility managers is often that such programs are too expensive. Dickens had no problem with challenging this point of view either.

Whenever a Coketowner felt he was ill-used-that is to say, whenever he was not left entirely alone, and it was proposed to hold him accountable for the consequences of any of his acts – he was sure to come out with the awful menace, that he would ‘sooner pitch his property into the Atlantic.’ This had terrified the Home Secretary within an inch of his life, on several occasions.

However, the Coketowners were so patriotic after all, that they never had pitched their property into the Atlantic yet, but, on the contrary, had been kind enough to take mighty good care of it.

You are welcome to use our Safety Moments in your workplace. But there are restrictions — please read Use of Safety Moments.

Copyright © Ian Sutton. 2018. All Rights Reserved.