This is the fourth edition of CSA Z259.10, Full body harnesses. It supersedes the previous editions published in 2012, 2006, and 1990. The purpose of this Standard is to specify requirements for the design, testing, performance, marking, and instructions for use of full body harnesses. Major changes to this edition include the following: a) the addition of a new Class of full body harnesses, Class R: Arc resistant; b) the addition of a new requirement to ensure all full body harnesses permanently incorporate a waist belt or back strap or other means of controlling the separation of the shoulder strap on the back of the full body harness (Clause 4.5); c) the addition of a new informative annex (Annex A) providing guidance on the sample requirements for full body harnesses; d) the dynamic drop test procedure for Classes A, D, E, L and P have been updated allowing for flexibility in free-fall height while maintaining the 16 kN (3600 lbf) maximum arrest force to allow for more rigid materials and constructions; and e) the references (Clause 2) and definitions (Clause 3) have been updated.