This Part of the European Standard EN 13445 specifies requirements for the design of unfired pressure vessels covered by EN 13445-1:2009 and constructed of steels in accordance with EN 13445-2:2009. EN 13445-5:2009, Annex C specifies requirements for the design of access and inspection openings, closing mechanisms and special locking elements. This Part applies to design of vessels before putting into service. It may be used for in service calculation or analysis subject to appropriate adjustment.