Re: [SystemSafety] words you cannot use at GM

From: Maier, Thomas < >
Date: Wed, 21 May 2014 08:14:51 +0000

A correction regarding IEC 615011:
That minimum failure rate per IEC 61511 is specified in Part 1 clause 8.2.2: “The dangerous failure rate of a BPCS (which does not conform to IEC 61511) that places a demand on a protection layer shall not be assumed to be better than 10-5 per hour.”

A question regarding legal damages by non-zero risk statements: The US National Electrical Code for machinery (standard NFPA 79) normatively requires: “Where failures or disturbances in the electrical equipment cause a hazardous condition or damage to the machine or the work in progress, measures shall be taken to minimize the probability of the occurrence of such failures or disturbances.” It informatively refers to IEC 61508, IEC 62061, ISO 13849 in this context, i.e. to standards which are based on probabilistic quantification of risk. How much legal protection do you actually get as a manufacturer in a liability law suit under US jurisdiction by showing compliance to NFPA 79? And in the automotive domain: How about ISO 26262, which also allows quantitative arguments in the safety case for programmable electronic controls on board road vehicles, and which has been written and is supported by the global automotive industry as state-of-science-and-art?

A comment regarding the qualification as “Orwellian” of the 69 words (by the way I was only aware of the “Milwaukee 7” so far, should these be called the “Detroit 69”? …☺): Even though the list looks a bit funny to me, I think this is the kind of language regulation you generally want for technical / scientific writing. I cannot see any corporate agenda of truth-hiding or any other evil intention behind. And please note also that the word “safety” is not forbidden. Guidance is provided, very much in line how “safety” is used in functional safety standards.

Med venlig hilsen / Best regards / Mit freundlichen Grüßen

Thomas Maier
E: Thomas.Maier_at_xxxxxx T: +45 42 13 74 52

Fra: systemsafety-bounces_at_xxxxxx Sendt: 21. maj 2014 09:20
Til: systemsafety_at_xxxxxx Emne: Re: [SystemSafety] words you cannot use at GM

This would seem to be one of the disadvantages of not taking IEC/ISO standards seriously. In European arbitration, the claim "the applicable international standard says...." is mostly taken very seriously by the arbitrators, I understand.

Not that the standards are perfect, or even wonderful..... :-) But they do tend to say " there is no such thing as zero risk". Indeed, in IEC 61511 you're only "allowed" to assume that an otherwise-unqualified process control system has a failure rate of 1 in 10 ophours or worse.

PBL Prof. Peter Bernard Ladkin, University of Bielefeld and Causalis Limited

On 21 May 2014, at 00:02, Eric Scharpf <EScharpf_at_xxxxxx Unfortunately this is not surprising. I have dealt with other US companies which have indicated that any statement acknowledging a non-zero risk from their equipment invites legal damages in potential product liability lawsuits.

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systemsafety_at_xxxxxx Received on Wed May 21 2014 - 10:15:19 CEST

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