This document has been produced by the convenors of CEN/TC158 working groups. It is intended to serve as a guide, to be consulted when drafting new EN standards for head protection and when revising or amending existing ones. Whilst implementation of its contents is not mandatory, working groups are urged not to make deviations from this guidance document without good cause. This is a living document - omissions will be covered in later issues. In this document, reference is made FprCEN/TR 16148, Head and neck impact, burn and noise injury criteria. This gives further guidance about the areas of the head which helmet standards should aim to protect, and about head and neck injuries. The working group should assess the foreseeable risks against which the helmet should provide protection. Each of the helmet standards should provide for a helmet, which will offer optimum protection to the head against these foreseeable risks and should satisfy the Basic Health and Safety Requirements of EU Directive 89/686/EEC to the extent indicated in annex ZA of the helmet standard. Helmet standards should indicate, in an informative annex, how the level of performance requirements specified relates to the severity of injury to be tolerated. Working groups should refer to FprCEN/TR 16148 when drafting this annex. Reference is also made to EN 13087, Protective helmets, Test methods. This standard provides harmonized methods of test for many of the topics listed below. The various parts of EN 13087 are listed in the Bibliography.