Pressurisation System in Buildings

• In a multi-storey buildings , stairways and lobbies may be air pressurised to clear smoke  and provide an unimpeded escape route . 
• It is installed to keep protected escape routes of a building clear of smoke . 
• It inroduces fresh air to maintain a postive pressure in the protected area . 
• May be omitted if there is sufficient provision of natural ventilation . 
• It is important to provide openings ( window ) so that smoke is displaced from the escape routes to the outside air .