For most individuals, the average time for alcohol to leave your body is around an hour per one unit you consume. Though this statistic is different for addiction suffers who build up a high tolerance to alcohol and will subsequently be able to eliminate it from their system a lot more quickly. Other factors such as weight, age, gender, the strength of alcohol consumed and how much food you have eaten can also have an effect on how quickly you are able to remove alcohol from your system.
1 unit of alcohol is approximately 10ml of alcohol, to put that into perspective there are 2 units in an average pint of beer. So, based on the estimates above it can take up to 10 hours for 5 pints beer to leave the average person's system after consuming.