Engineering in an Age of Limits

Discusses the role of engineers as society enters an Age of Limits — particularly with oil supplies.

The One-Legged Stool


We are currently writing a series of posts to do with systems analysis and how process safety expertise can help contribute to an understanding of such systems. The first two posts in this series are:

  • APEC Blue which discussed the ignored, yet very real, costs of externalities; and
  • The Cloud which pointed out that externalities go beyond simple environmental issues, and that, sooner or later, we — all of us — will have to pay for them.

The background to this series is that we have entered an Age of Limits (economic, energy and environmental). Like it or not our world is going to get much simpler. It behooves those of us who are aware of this wrenching change to get out ahead of the curve. (An excellent introduction to these three topics is provided by Chris Martenson in his ‘Crash Course’. It consists of 26 presentations, each of which lasts for ten minutes. Time spent listening and watching these presentations is time very well spent.) And, I would like to think that that those trained in process safety management already have a good grasp of systems thinking.

In the previous paragraph I used the phrase ‘Like it or not’. Our world is going to get simpler. We can deny the changes that are taking place; we can believe that “they” (whoever “they” are) will come up with something; or we can just hope for the best. None of these reactions make any difference: “Nature bats last”. Moreover, simplification is not going to be pretty — a topic we will discuss in future posts. But it would be irresponsible to deny the existence of the predicament in which we find ourselves. We need to take action — time is not on our side.

Collapse Now and Avoid the Rush

John Michael Greer

John Michael Greer

In previous posts I have cited the works of John Michael Greer. Since the year 2006 he has been writing a remarkable and very successful weekly blog entitled The Archdruid Report in which he clearly spells out the dilemmas that we face. In one of his posts he reports that, when speaking at one conference, he spontaneously came up with the phrase, “Collapse Now and Beat the Rush”. It is useful to provide the context in which he made the remark.

One of my presentations to that conference was a talk entitled “How Civilizations Fall;” longtime readers of this blog will know from the title that what I was talking about that afternoon was the theory of catabolic collapse, which outlines the way that human societies on the way down cannibalize their own infrastructure, maintaining themselves for the present by denying themselves a future.  I finished talking about catabolic collapse and started fielding questions, of which there were plenty, and somewhere in the conversation that followed one of the other participants made a comment. I don’t even remember the exact words, but it was something like, “So what you’re saying is that what we need to do, individually, is to go through collapse right away.”

“Exactly,” I said. “Collapse now, and avoid the rush.”

Outside of that conversation, I doubt I would have thought of the phrase at all. By the end of the conference, though, it was on the lips of a good many of the attendees, and for good reason: I can’t think of a better way to sum up the work ahead of us right now, as industrial society lurches down the far side of its trajectory through time.

In other words, society as we know it — including the energy and process industries — is going to collapse (or at least change radically, whether we like it or not) and it us up to use to take charge of our destinies.

Greer’s theory to do with ‘catabolic collapse’ is fascinating and deserves a thorough treatment in future posts in this blog series. But Greer and most of his readers are not, like most of the readers here, engineers or process safety specialists. His audience tends to focus on how individuals can respond to the dilemmas that we face or how political and social systems need to change. The challenge that faces those of us who work in industry  is how to simplify industrial processes while maintaining our standards of safety and environmental responsibility.

Which brings us to Trevor Kletz and his one-legged stool.

The One-Legged Stool

I haveKletz-Trevor-1 had occasion on a number of times to refer to Trevor Kletz and his ability to tell stories (see my post That would be telling.) One of his better known stories was to do with the one-legged stool.

Early in the 20th century a factory in England manufactured the dangerous explosive nitro-glycerine. The worker in charge of this process (the rather stout gentleman shown in the picture at the head of this post) was allowed to sit down but only on a one-legged stool. Hence if he dozed off he would fall and wake up. (Further information to do with this primitive, yet effective safety technique is provided at the Wat Tyler Country Park site.) The following is a quotation from that site.

Highly unstable nitro-glycerine was the main ingredient of explosives made at the Pitsea factory. Making nitro-glycerine was very dangerous. Concentrated acids were mixed with glycerine in huge vats. If too much glycerine was added too quickly to the mixture, it would become unstable, and a large valve would have to be opened to quickly dump the whole batch into a large vat of water. Failure to do this quickly could have led to a catastrophic explosion.

Mostly, though it was very dull. The operator would sit at the mixing machine for long hours just looking at the dials to make sure the machine was working OK, and there was a good chance they could fall asleep on the job. A one-legged stool made sure they had to perch to stay awake. At Pitsea it seems this was very effective, because in all the years the factory operated they never once had to dump the Nitro-Glycerine mixture.

Strapping-Gauge-1It might be thought that the time and place of this example is so distant as to be not pertinent to modern industry. But I recall, early in my career, working at chemical plants in south-east Texas and in Europe where the clients made large quantities of ethylene oxide (EO) — a chemical that is both toxic and highly flammable. EO was stored in a large intermediate tanks (I would say at least 15 meters tall) that had absolutely no instrumentation at all — none, zippo. The only way of measuring the level was with a manual strapping gauge. To modern eyes this situation sounds extraordinarily hazardous, yet it worked — in many years of operation neither facility had a spill or any other type of incident to do with intermediate tanks.

But the modern safety engineer could not live with such a situation, not least because it probably contravenes some industry standard or regulation. So he or she would carry out lengthy and expensive “studies” and determine that “something must be done” — even though there really isn’t a problem to be solved. The final recommendation will be that a sophisticated level control system be installed, backed up with a high-integrity Safety Instrumentation System.

This new system may or may not make the operation of the tank more safe but it will most certainly increase capital and maintenance costs by orders of magnitude. And, more important, a complex system such as this is vulnerable to the Law of Unintended Consequences. If something can break it will. But with the one-legged stool, all that can break is the leg of the stool itself, and that can be fixed in no time flat.

The increased complexity of the solution to the “Nitro-Glycerine (non-) problem” shows up in the elements of process safety.

  • Process Safety Information.
    Stool: Very little information needed and none of it needs to be written down; stools have been in used for millennia; we know how they work and what they do.
    Instrumentation: Extensive; subject to error; out of date almost immediately; expensive to record and keep up to date.
  • Operating Procedures
    : Short — keep an eye on the level and temperature and level in the vessel; turn one valve if things go awry.
    Instrumentation: Extensive; complex; expensive.
  • Maintenance
    : Negligible – the workshop can fix any problems in minutes.
    Instrumentation: Complex, subject to error and vulnerable to lack of skilled personnel; expensive.
  • Prestartup Review
    Stool: Sit on it, the test is complete in seconds.
    Instrumentation: Lengthy, needs checklists; leads to acrimonious meetings; expensive,

Of course, the above is written somewhat tongue-in-cheek. But the attractiveness of simple solutions cannot be denied yet it invariably avoided.

Back to Trevor — he and his colleagues recognized the value and elegance of simplicity. They made it the fifth leg of the stool of Inherent Safety.

  1. Eliminate
  2. Minimize
  3. Substitute
  4. Moderate
  5. Simplify

But there is a profound difference between what Trevor propounded and what we are discussing in this blog series.

In Trevor’s day simplification was a choice. In the Age of Limits simplification is going to happen — like it or not. The challenge that we are faced with is not “How do we make our processes simpler?” but “Given that our processes are going to become simpler how do we manage this transition and still maintain our standards of safety and environmental performance?”


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