A minimum standard of medical fitness is prescribed for personnel who apply for re-engagement in the Permanent Defence Force. The prescribed minimum keenness of hearing standard for extension of service for personnel who enlisted on five year service engagements in 1994, is Grade 2 as prescribed in Defence Force Regulations A. 12. This standard requires that an individual's keenness of hearing must be not worse than the age related warning level prescribed in the guidelines on hearing checks and audiometry issued by the health and safety authority. Personnel who do not meet the prescribed standard will not be permitted to extend their service.