Can't exceed. In the current Code for Catering Industry, the stipulation of "connecting hose between gas appliance and pipeline" is firstly quoted from the Technical Code for Compulsory Standard of Town Gas (GB 50494-2009), and the interpretation of its provisions points to the Code for Design of Town Gas (GB50028-2006). When the hose is connected to the household gas appliance, its length should not exceed 2m, and there should be no interface.