Gives a summary of the test methods that are used in the assessment of smoke obscuration. It presents a brief summary of static and dynamic test methods in common use, either as international standards or national or industry standards. It includes special observations on their relevance to electrotechnical products and their materials and to fire scenarios, and it gives recommendations on their use. The main changes with respect to the previous edition are listed below: - updated normative references; - expanded terms and definitions; - numerous editorial changes of a technical nature throughout the publication. Has the status of a basic safety publication in accordance with IEC Guide 104.