This part of EN 1335 specifies the mechanical safety requirements for office work chairs. The requirements are based upon use for 8 h a day by persons weighing up to 110 kg. For more severe conditions of use, increased requirements will be necessary. Annex A (normative) includes loads, masses and cycles for safety tests. Additional loads, masses and cycles for functional tests can be found in EN 1335-3:2009, Annex C.