Hello, A top vent can be ON A kitchen, at the statutory height? Does the gas stopcock of the cabinet of a hot water tank that is outside must be on the external side? At what height? On the other hand, I would like to know if it has vents, in addition to the chimney. In addition I have to cover 1mt of SIGAS pipe and I have Poliguard, I would like to know if it works or is there any alternative, or yes or yes is the coating that they sell for hot melt. Thanks in advance, regards!