Risk analysis relevant for laser products under IEC 60825-1

Abstract

While there are deterministic rules laid down in IEC 60825-1 regarding how to determine the accessible emission for the nominal output and classify a laser product, there are also aspects where a probabilistic risk analysis is important. With the revision of IEC 60825-1 (third edition), the role of risk analysis will be emphasized and somewhat widened. Examples where risk analysis plays a role are: is a single fault relevant for classification (i.e. reasonably foreseeable); is additional functional safety (automated power reduction for case of fault) needed; is it permitted that automated power reduction is not fast enough to assure AEL is not exceeded; design of scanning safeguards; and reliability of interlocks. Also, independent of the above issues of functional safety, it should be noted that governmental market surveillance agencies in Europe use risk analysis to decide if a product (such as a Class 3R laser) is acceptable to be marketed as consumer product or not. In this paper, the principles of risk analysis will be discussed as well as examples given where risk analysis has an important role for the manufacturer of a laser product. This paper offers a first input to develop guidance how risk analysis and IEC 61508 in particular can be applied in the design of a laser product.While there are deterministic rules laid down in IEC 60825-1 regarding how to determine the accessible emission for the nominal output and classify a laser product, there are also aspects where a probabilistic risk analysis is important. With the revision of IEC 60825-1 (third edition), the role of risk analysis will be emphasized and somewhat widened. Examples where risk analysis plays a role are: is a single fault relevant for classification (i.e. reasonably foreseeable); is additional functional safety (automated power reduction for case of fault) needed; is it permitted that automated power reduction is not fast enough to assure AEL is not exceeded; design of scanning safeguards; and reliability of interlocks. Also, independent of the above issues of functional safety, it should be noted that governmental market surveillance agencies in Europe use risk analysis to decide if a product (such as a Class 3R laser) is acceptable to be marketed as consumer product or not. In this paper, the principles of ri...