Re: [SystemSafety] Functional hazard analysis, does it work?

From: Matthew Squair < >
Date: Tue, 19 Jan 2016 13:20:49 +1100


Thx Andy,

Though I'm not a Dr, that's the wife. :))

Matthew Squair

MIEAust, CPEng
Mob: +61 488770655
Email; Mattsquair_at_xxxxxx
Web: http://criticaluncertainties.com

> On 19 Jan 2016, at 12:25 PM, andy <loeblas_at_xxxxxx >
> Dr. Squire;
> I have had these same kinds of questions in the past. I have studied the relationship between probabilistic and non-probabilistic risk assessment mostly as a result of a project I worked on for the U.S. Nuclear Regulatory Commission regarding digital systems reliability versus non-digital systems for safety critical power reactor control. I have also studied the statistical work executed by the London folks on common cause failure and defense in depth. I believe probabilistic risk assessment is a bureaucratic, reductionist, and none to complete analysis of risk assessment focused on a “guns and guards” mentality dominant in the USA. I have written, 3 or 4 years ago, white papers on my conclusions and readings and done some graphic representations of the NRC regulations on common cause failure. I have studied Nancy Leveson’s systems approach and taken her week long course, also 3 or 4 years ago, and I have developed a favorable disposition towards her conclusions. My white papers were written to keep my own thinking organized and I can look for any of the products I developed for this purpose as well as share my bibliographies with you, although some of the documents from the city college folks in England were given to me as a professional courteousy and these references might be listed but not available for re-distribution according to my agreement.
>
> Let me know if any of this would be useful to you. It will take me a week or two to relocate the digital versions of this stuff.
>
> andy
>
>
>
> From: systemsafety-bounces_at_xxxxxx > Sent: Monday, January 18, 2016 7:43 PM
> To: systemsafety_at_xxxxxx > Subject: [SystemSafety] Functional hazard analysis, does it work?
>
> A question to the list.
>
> Does the process of functional hazard analysis 'work' in terms of identifying all functional hazards that we are, or should be, interested in?
>
> The way the FHA process is defined in the various standards seems IMO to be very reductionist in nature, fine for identifying the specific consequences of a single functional failure mode, but what about functional interactions, multiple functional failures, the interaction of modes with functions and so on.
>
> The background to this is that the project I'm working with is about to commit to a significant campaign of 'FHA'-ing. So we're engaged in a little bit of professional navel gazing about the efficacy of the technique before we commit to the campaign.
>
> --
> Matthew Squair
>
>
> BEng (Mech) MSysEng
> MIEAust CPEng
>
> Mob: +61 488770655
> Email: MattSquair_at_xxxxxx > Website: www.criticaluncertainties.com
>



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systemsafety_at_xxxxxx Received on Tue Jan 19 2016 - 03:21:19 CET

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