This International Standard specifies requirements for adult and paediatric tracheostomy tubes and connectors. Such tubes are primarily designed for patients who require anaesthesia, artificial ventilation or other respiratory support. This International Standard is also applicable to specialized tracheostomy tubes that share common attributes, for example, those without a connector at the machine end intended for spontaneously breathing patients and those with reinforced walls or tubes made of metal or tubes with shoulders, tapering tubes, tubes with provision for suctioning or monitoring or delivery of drugs or other gases. Flammability of tracheostomy tubes is a well recognized hazard (for example, when electrosurgical units or lasers are used with flammable anaesthetic agents in oxidant-enriched atmospheres) that is addressed by appropriate clinical management and is outside the scope of this International Standard. NOTE ISO/TR11991 gives guidance on avoidance of airway fires.