Ventilation is a key method of making the built environment into a comfortable space for users to exist in. It keeps a fresh flow of air into a building ensuring the partial removal of odour and excess heat. The collage above represents the basic air flow of a ventilated area.  It starts with the harvesting of fresh air into the space, this can be done using a number of methods; the most common being either having the air flow naturally in through an opening or by using fans to mechanically bring fresh cool air in. Once in the space the fresh air will stagnate and become stale, this is normally down to air usage of users in the space, smells in the space and heat which is normally given off by users and machinery. The stale air through heating up and fresh air being introduced into the space is forced upwards this is normally a suitable place for an opening to release the stagnant air out of the space and back into the atmosphere where it can be converted back into fresh air. 

These principles are split into three sections: