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Investigation Committee of Safety Standards

Purpose and Progress of Safety Quantification Proposal
- Rank Matrix Method for Safety Diagnostics of Complex Systems -


To develop a technical guideline for system safety by using the Rank Matrix Method


In the case of safety issues, inherent safety has been emphasized for the mechanical systems since 1989, and no effort for the quantification of safety has been made.

However, systems containing electronic control devices and software systems have remarkably increased recently and their safety could not be expressed in the inherent safety.
As one of the quantification standards for the safety related to electronic systems (IEC61508)(functional safety) was published in 1998, which evaluates safety with risks.

When analyzing accidents of a complex system, it is usual that human being get involved in them. With such the complex system, it is recommendable to study associated primary causes with matrix comprehensively and try to obtain the optimum state resulting from quantifying evaluation with all elements of the matrix.
For this reason, we Investigation Committee of Safety Standards, proposed Rank Matrix Method as an evaluation method for complex systems to the IEC, international organization. Since no organization of TC was available with this issue, we intended to archive the Rank Matrix Method as a TTA(Technical Trend Assessment - a kind of international standards documents).

PDF File

In 2001, a document titled Matrix Rank Method for safety evaluation of complex systems completed and after review of domestic IEC committee members, it was offered to IEC Central Office as a level of TTA, which means Technical Trend Assessment, a kind of international standard category.
Acceptance as TTA of IEC standards for this unique proposal took a voting methods by member of SMB(standards management Boards of IEC) and this proposal was rejected by the result that positive vote in not over 2/3, but over 1/2. (Oct.2002)

However, we believe that proposed idea on safety evaluation, that is a way of quantitative on safety significance, was evaluated as an excellent application method for complex systems safety under the modern industries.

Continuing Efforts

The sub-committee intends to develop a new technical guideline which is included into enhancement and expansion of Matrix Rank Method based on the original document. The title of document was revised to "Rank-Matrix Method for safety diagnostics of complex systems", and its contents are structured as follows ;

1. General concept,
2. Requirement,
3. Application for integrated manufacturing systems,
4. Application for building s and facilities.

The subcommittee is encouraging new safety experts from different industries to participate in this task to obtain the new promising goal.

MEMBER of safety diagnostics method special working group of IEICE

Yoshihisa Suzuki
Yoshiyuki Mineo
Takeshi Natsume
Kazuhiro Hayashi
Yasuko Orihara
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