Re: [SystemSafety] Risk Based Planning and Assessment - tank farms

From: Carl Sandom < >
Date: Tue, 18 Dec 2012 10:12:07 -0000


You're definitely not alone in your thinking. An interesting book on the topic of risk assessment which is in agreement with your view is: The Black Swan: The Impact of the Highly Improbable by Nicholas Taleb. I presented a paper at the Australian System Safety Conference in 2011 where I raised some of the problems I have encountered relating to risk assessments, one problem typically being an over reliance on 'expert judgement' (you can find the paper at if you're interested). In my experience there is nearly always a need to improve the validity of safety assurance (i.e. risk assessment) claims through the use of meta-evidence (e.g.. present evidence about evidence to answer questions such as: who made the expert judgements?, how competent were they to do so? etc.).  

Best Regards


Dr. Carl Sandom PhD CEng FIET MIEHF

Director and Consultant

iSys Integrity Limited

10 Gainsborough Drive


Dorset, DT9 6DR

United Kingdom


From: systemsafety-bounces_at_xxxxxx
[mailto:systemsafety-bounces_at_xxxxxx Ronback
Sent: 18 December 2012 04:34
To: systemsafety_at_xxxxxx Subject: Re: [SystemSafety] Risk Based Planning and Assessment - tank farms  


Thanks for your thoughts on the subject.

In addition to natural hazards, I'm also interested in how effectively city planning departments make use of risk based planning and assessment for developing industrial areas near residential ones, e.g. jet fuel tank farms. I gather some recommendations were made in the UK after the Buncefield incident in 2005, but regulations are still in the works in the UK since nothing has been published yet.


COMAH - Buncefield: Why did it happen? - HSE

Learning the Lessons from Buncefield 0/Sevesokonferansen%202010%20-%20Learning%20the%20lessons%20from%20Buncefiel d.pdf


RE: [SystemSafety] Risk Based Planning and Assessment


Mon, 17 Dec 2012 10:51:41 -0500


Loebl, Andy <mailto:loeblas_at_xxxxxx


James Ronback <mailto:jim_ronback_at_xxxxxx  

My experience in the United States is with the Department of Homeland Security and the Nuclear Regulatory Commission. To me risk based planning and assessment processes to not hold my confidence. Even probabilistic risk assessment methods, as employed here, seems both weak and unsubstantiated. To me, the practice is based on "expert judgment" which I interpret as someone, somewhere, is guessing and somehow this is codified and legitimatized. Unless, of course, there is someone higher up in the decision making process who disagrees with the expert judgment, for personal, political, or even professional reasons and decides to change that judgment, which in turn becomes
codified and legitimatized.  

For example, regardless of the probability, how many mega-quakes, like Yellowstone, are we willing to accept? Since the average frequency has been ~600,000 years between eruptions and the last one was 640,000 years ago,
does that mean we should move out of the areas likely to be affected or what should those people living in the
affected areas do? Mt. Fugi is another example. People in Japan have populated the hillsides of the volcano, and like Mt. St. Helens, Fugi will erupt certainly soon, in geologic time, but what should be done today?  

In short, the only way to really have confidence in the guessing that goes into even the best risk assessments,
users of those assessments cannot be allowed to use those assessments at a scale for which it is not intended.
Determining risk values, as the U.S. Coast Guard and homeland security does, and quantifies the results at an
interval scale, to my way of thinking, is taking 'judgment' too far.  

I think I am alone at this thought. I also have not studied my objections enough to offer alternatives. I hope
all this makes sense to you.  


-----Original Message-----
From: systemsafety-bounces_at_xxxxxx
[mailto:systemsafety-bounces_at_xxxxxx On Behalf Of James Ronback
Sent: Sunday, December 16, 2012 5:17 PM
To: systemsafety_at_xxxxxx Subject: [SystemSafety] Risk Based Planning and Assessment    

Which countries have risk based planning and assessment processes that you would recommend or deprecate?  

Jim Ronback, P. Eng. (System Safety Engineer - retired)    

No virus found in this message.
Checked by AVG -
Version: 2013.0.2805 / Virus Database: 2634/5954 - Release Date: 12/12/12  

The System Safety Mailing List

No virus found in this message.
Checked by AVG -
Version: 2013.0.2805 / Virus Database: 2637/5965 - Release Date: 12/16/12

The System Safety Mailing List
systemsafety_at_xxxxxx Received on Tue Dec 18 2012 - 11:12:45 CET

This archive was generated by hypermail 2.3.0 : Tue Jun 04 2019 - 21:17:05 CEST