This Defence Standard specifies the standards for the power, water, waste and fuel infrastructure in an operational base or headquarters and for the interfaces to it. It includes the mechanical interfaces together with requirements for contractual information deliverables and verification. The data infrastructure and information requirements necessary to support Facilities Management in a base are included as guidance. When they are sufficiently matured the Def Stan will be updated to reflect this. The application of the GBA Approach is mandatory but is tailorable.