The IEC-standards 61508 (”Functional safety of safety-related systems”) and IEC 61511 (Functional safety — Safety instrumented systems for the process industry sector) provide useful information and guidance on safety requirements regarding the use of Safety Instrumented Systems (SIS). In the latest "PDS Method Handbook" the notation has been further updated in order to be in line with the IEC standard. The objective has been to “keep the best of the PDS method and at the same time to adapt the method to terms and requirements in IEC”.

New features of this 2010 Edition of the PDS Method Handbook include:

• A general review and update of the methodology and the formulas, including a more in depth discussion of the assumptions underlying the formulas;
• An update of the model for common cause failures (CCF) in multiple redundant systems;
• A discussion on the use of the method for continuously (high demand mode) operating systems;
• Some new and revised terminology.

An electronic version (in PDF-format) of the first three chapters of the PDS Method Handbook can be viewed here.