The National Fuel Gas Code is the result of the American Gas Association, the American Society of Mechanical Engineers, and the National Fire Protection Association joining together to combine various standards into a single entity. The code offers general criteria for the installation and operation of gas-fired equipment, including venting.
There are many reasons you should follow the guidelines of the National Fuel Gas Code when venting gas-fired appliances. First and foremost, the products of combustion include carbon monoxide (CO). When improperly vented from the building, these products could be potentially fatal to the building occupants-leaving you liable. In addition, improper venting could result in premature failure of both the vent and hydronic equipment from condensation formation inside the vent. These problems can be prevented by following all guidelines in the National Fuel Gas Code and the equipment manufacturer's installation requirements.