This standard specifies the requirements and test methods for positive pressure air/flue terminals with metal flue ducts for C62- and C63-type gas appliances, which convey air for combustion, and the products of combustion from appliances to the outside atmosphere.It also specifies the requirements for marking, manufacturer’s instructions, product information and evaluation of conformity.NOTEThe classification of gas appliances is according to CEN/TR 1749.