In the Gas Distribution business Unaccounted Gas is referred to by various names or terms such as:
Lost and Unaccounted-For, LUG, L&U, and UAF. In simplest terms, Unaccounted Gas is the result of the formula “gas receipts minus gas deliveries”. For the Measurement Group the process amounts to a “gas inventory reconciliation” based on the recorded volumes into the system(s) less the sum of the volumes out of the system(s). This can be a town by town or a total-system reconciliation.