The standard specifies the basic terminology and methodology, and sets out principles of risk assessment and risk reduction to help designers in achieving safety in the design of machinery. This document combines the contents of the previous standards DIN EN ISO 12100-1:2004 and DIN EN ISO 12100-2:2004, including the 2009 Amendments to both standards and the standard DIN EN ISO 14121-1:2007. According to the decision of ISO/TC 199, the technical amendments with regard to the previous documents are limited exclusively to contents, which are related to the revised Machinery Directive 2006/42/EC. For this reason, documentation (for example, for risk assessment or type-C standards) based on the previous documents need not be updated solely because this new edition has been published. The International Standard on which this standard is based has been prepared according the Vienna Agreement by Working Group 5 "General principles for the design of machinery and risk assessment" of ISO/TC 199 "Safety of machinery", in collaboration with CEN/TC 144 of the same name (all secretariats: DIN). The responsible German standardization committee is Joint Working Committee NA 095-01-01 GA "Allgemeine Grundsätze und Terminologie" ("General principles and terminology") of NASG with NAM and DKE.