This part of EN 13384 specifies methods for calculation of the thermal and fluid dynamic characteristics of chimneys serving more than one heating appliance. This part of EN 13384 covers both the cases, either (1) where the chimney is connected with more than one connecting flue pipe from individual or several appliances in a multi-inlet arrangement or (2) where the chimney is connected with an individual connecting flue pipe connecting more than one appliance in a cascade arrangement. The case of multiple inlet cascade arrangement is covered by the case (1). This part of EN 13384 deals with chimneys operating under negative pressure conditions (there can be positive pressure condition in the connecting flue pipe) and with chimneys operating under positive pressure conditions and is valid for chimneys serving heating appliances for liquid, gaseous and solid fuels. This part of EN 13384 does not apply to: - chimneys with different thermal resistance or different cross-section in the various chimney segments. This part does not apply to calculate energy gain. - chimneys with open fire places, e. g. open fire chimneys or chimney inlets which are normally intended to operate open to the room - chimneys which serve a mixture of fan assisted or forced draught burners or natural draught appliances. Fan assisted appliances with draught diverter between the fan and the chimney are considered as natural draught appliances. - chimneys with multiple inlets from more than 5 storeys. (This does not apply to balanced flue chimney.) - chimneys serving heating appliances with open air supply through ventilation openings or air ducts, which are not installed in the same air supply pressure region (e. g. same side of building). For positive pressure chimneys this part only applies if any heating appliance which is out of action can be positively isolated to prevent flue gas back flow.