Single Fault Condition – Clause 4.7 of Third Edition IEC 60601-1 – Part 1

25 Apr 2011

This month, several of the blog topics explored the risk management policy as it relates to Third Edition IEC 60601-1. Specifically, these blog entries took a closer look at Clause 4.2 – the policy for determining acceptable risk and the acceptability of residual risk(s) shall be established by the manufacturer. As a result, these entries highlighted how important it is for the manufacturer to submit the appropriate RMF checklists and supporting documentation to a third-party testing company before submitting the device for evaluation. But why is this important?

Clause 4.7 of Third Edition IEC 60601-1 is the policy clause on single fault condition for medical device equipment. The risk needs to remain acceptable as determined through the application of Clause 4.2. That said, medical equipment has to be designed and manufactured so there are no unacceptable risks after single fault are applied. Both Clause 4.2 and 4.7 work in tandem to ensure that the risk management files are acceptable

Medical equipment is considered free of unacceptable risk by the following criteria:

• The device/equipment employs a single means for reducing risk that has a negligible probability of failure; and/or
• A Single Fault Condition occurs, but: the initial fault will be detected during the Expected Service Life of the ME Equipment and before a second means for reducing a Risk fails or – the probability that the second means of reducing the RISK will fail during the Expected Service Life of the ME Equipment is negligible

"If a single fault condition occurs and there is no unacceptable risk, it can be considered comply with the standard." said Todd Konieczny North American Medical Technical Leader. "

During any test under single fault condition, only one fault at a time shall be applied. On May 9, we will explore how risk analysis shall be used to determine which failures shall be tested.

To learn more about Third Edition and or to speak with an Intertek expert on this subject matter, e-mail us at ThirdEdition@intertek.com