UL 1738 and ULC-S636 Venting Systems and the Fuel Gas Codes
2020-11-20
UL 1738, Venting Systems for Gas-Burning Appliances, Categories II, III, and IV, and ULC-S636, Standard for Type BH Gas Venting Systems, cover vents in the USA and Canada for a subset of gas-fired products where flue gas temperatures are typically reduced. Energy conservation initiatives and principles intended to make more efficient use of resources require that certain gas-fired appliances operate with unique venting materials that are more resistant to corrosion and degradation.
