This European Standard applies to the design, construction, equipping, marking and testing of air locks as defined in 3.3 including pressure bulkheads as defined in 3.4, which are to be used in tunnelling work. An oxygen breathing system used to provide the breathing supply necessary to conduct a safe decompression is also covered by this standard.This European Standard is not applicable to machinery and equipment which is manufactured before the date of publication of this document by CEN.NOTEAir locks can be connected to tunnelling machinery. This standard can help the design of air locks and bulkheads in other compressed air work in construction.This European Standard deals with all significant hazards, hazardous situations and events relevant to such machinery when they are used as intended and under conditions of misuse which are reasonably foreseeable by the manufacturer (see Clause 4).This European Standard does not cover the supply of services to the air lock.Vibration, noise and EMC (Electromagnetic compatibility) hazards are not significant hazards for air locks.This European Standard does not cover the hazards due to the mobility of the machinery.