1.1 The requirements given in Clause 1 of the General Standard apply with the following additions and modifications:

1.1.1 Replace 1.1 with the following:

1.1.1.1 This specification includes requirements for the safety and performance of active vaporizing and nebulizing humidification systems, as defined in 3.6, suitable for inclusion in breathing systems (both intubated and nonintubated patients).

1.1.1.2 This specification also includes requirements for breathing tubes, including heated breathing tubes (heated-wire breathing circuits), and devices intended to control these heated breathing tubes, heated breathing tube controllers.

1.1.1.3 Heat and moisture exchangers (HMEs) are outside the scope of this specification. However, it is recognized that their safety and performance may affect that of humidification systems. Numerous studies have been published citing the benefits and risks of HMEs used in conjunction with humidification systems. It is advisable to review the instructions for use provided with the humidification systems and HMEs and the available literature for more details.

1.1.1.4 Devices commonly referred to as "room humidifiers," humidifiers used in heating, ventilation, and airconditioning systems and humidifiers used to condition the environment within infant incubators are outside the scope of this specification.

1.1.1.5 It has not been found possible to include guidance on the matter of droplet size in the case of nebulizing humidifiers.

1.1.1.6 Gas-powered nebulizers used for the delivery of drugs to patients through their respiratory system are outside the scope of this specification.

1.1.1.7 Appendices in this specification are not mandatory unless made so by an explicit statement in the main text.

1.2 The values stated in SI units are to be regarded as the standard.