The purpose of an air gap is not really to allow air to escape but rather to keep dirty water from back flowing into the DW. An autovent allows air into the system to allow for proper drainage and an air gap is not dependant on one or vice versa. The autovent takes the place of a vent stack to the roof.
Sudan is a member of the United Nations, the African Union, the Arab League, the Organisation of Islamic Cooperation and the Non-Aligned Movement, as well as an observer in the World Trade Organization. Its capital is Khartoum, the political, cultural and commercial centre of the nation.
It is located in north east Africa. Sudan's land borders are with Egypt, Eritrea, Ethiopia, Kenya, Uganda, Democratic Republic of Congo, Central African Republic, Chad and Libya. To the east, it is bordered by the Red Sea. Sudan has an area of 2.5 million square kilometres. The area of the UK is 250,000 square kilometres. Sudan is roughly 10 times larger in land area than the UK. The official name of Sudan is Republic of the Sudan. Sudan's landscape is generally flat and featureless.