This Technical Specification sets out the framework and structure for the standard related to ventilation in hospitals. It gives the requirements for the drafting of the parts of the standard, including preliminary terms and definitions. The standard for ventilation in hospitals is intended for all healthcare premises where healthcare services are delivered. It is applicable for healthcare services located in a hospital, clinic or other premises. This includes general and specific risk areas, within healthcare and provides defined levels of air quality/cleanliness for classification of these areas. The standard addresses the minimum requirements for ventilation systems. It specifies the design, installation, operation, qualification process and maintenance of the ventilation systems. The standard describes the following hygienic issues related to the ventilation system: a) air quality (e.g. cleanliness levels, temperature, humidity, air quantity); b) the protection of patients, staff and visitors against harmful agents; c) reducing the growth of microorganisms (e.g. clean-ability, accessibility, wet surfaces, accumulation of particles); d) control of the airflow direction (e.g. tightness of systems and constructions, pressure difference). The standard describes a structured approaches for all phases from design up to and including maintenance and requalification and gives minimum requirements for the ventilation systems: a) minimum user requirement specification (URS); b) functional design requirements (FD); c) requirements for components in the detailed design (DD). This standard is intended for healthcare ventilation system project managers, designers, construction and commissioning engineers, estates managers and operations/facilities managers.