This manual provides much needed guidance on the longevity and maintenance requirements of mechanical and electrical plant (Ma&En). It sets out typical life spans of building service components– boilers, pipes, ventilating systems, hydraulic lifts, etc. These are ranked according to recognised benchmarks of specification, together with adjustment factors for differing environments, use patterns and operating regimes. Summaries of typical inspection and maintenance requirements are provided, along with specification guidance and references to further sources of information.