The fully vented one-pipe system

• This system is used in buildings where there are a large number of sanitary appliances in ranges  , example factory , schools , offices and hospital
• The trap on each appliance is gitted with vent pipe. 
• Individual vent ppes combine in a common vent for the range , which is inclining until it meets the vertical vent stack . 
• This vent stack may be carried to outside air or it may connect to the discharge stack at a point above the highest appliance. 
• The base at the vent stack should be connected to the discharge stack close to the bottom rest bend relieve any compression at this point .