Within the modern built environment, advanced engineering systems allow us to go about our daily lives in a relative degree of safety, comfort and security. Often, we do not give too much thought about what is happening behind the scenes. Every engineering system needs an energy source and control input to provide the service it is designed for. Without some degree of management, those engineering systems may not perform quite as intended. It is often unreliable to depend solely on building occupiers to satisfactorily control these engineering systems purely by manual means, and hence make the best use of the engineering systems for the benefit of all. The aim of this Code of Practice is to provide knowledge, understanding and good practice guidance on the design, evaluation, implementation and improvements on the use of automated controls used in mechanical and electrical engineering systems within the built environment. The Code of Practice also aims to provide clear and concise information on building automation and control systems that can be developed and applied to several different installations. There is often no single solution and therefore building controls must be specifically tailored to meet specific user needs, local technical requirements and the constraints of budget and resources.