[EN 12792:2003, 31]:component of a ventilation installation which is designed with the purpose of achieving the predetermined movement of air into or from a treated space. They can be divided into the following categories:automatically controlleddevices having moving parts which interact with a change in local conditions,such as temperature, humidity, CO2 concentration, pressure difference, airflow rate, etc.fixeddevices without any adjustable partsmanually adjustabledevices having adjustable parts which can be manually adjusted(see also components of air diffusion)