How High Should Sewer Vent Be Above Roof

I have a main vent and a sink vent and both are only 6 high above the roof.

How high should sewer vent be above roof.

If the roof area is for people then it is 7 ft above the roofing surface. Vent pipes shall terminate not less than 6 inches above the roof measured from the highest point where the vent intersects the roof. How high should the plumbing vents be above there roof. Does anyone know what legal height requirements there are for vent pipes from memory i m pretty sure that it must only be a minimum of 300mm above the gutters that s to ensure storm water does not get into the sewer system.

Where a roof is used for any purpose other than weather protection vents shall extend at least 7 feet above the roof and shall be properly supported. The slope is about 4 high for every 12 horizontal. All open vent pipes that extend through a roof shall be terminated at least 6 inches 152 mm above the roof and not less than 2 inches 51 mm above the invert of the emergency overflow except that where a roof is to be used for any purpose other than weather protection the vent extensions shall be run at least 7 feet 2134 mm above the roof. Some builders recommend a minimum of 30 cm 12 inches.

A vent terminal and depending if the roof is strictly for weather protection it terminates about 24 above the roof.