The ideal minimum size of the vent hole is 12 mm. The vent hole should be at least 8 mm. About 200 g of zinc ash will be produced for every square meter of the galvanized steel surface. Since ash is ...

“B” vent is double-wall. It is galvanized steel on the outside, with an aluminum inner pipe. B vent is rated only for gas appliances. It is used as a vent connector for all 78 percent and 80 percent ...