This International standard applies to the BASIC SAFETY and ESSENTIAL PERFORMANCE of FUNCTIONAL NIRS EQUIPMENT, as defined in 201.3.205, intended to be used by itself, or as a part of an ME SYSTEM hereinafter referred to as ME EQUIPMENT. HAZARDS inherent in the intended physiological function of ME EQUIPMENT or ME SYSTEMS within the scope of this document are not covered by specific requirements in this document except in IEC 60601-1:2005, IEC 60601-1:2005/AMD1:2012 and IEC 60601-1:2005/AMD2:2020, 7.2.13 and 8.4.1. NOTE – Additional information can be found in IEC 60601-1:2005, IEC 60601 1:2005/AMD1:2012 and IEC 60601-1:2005/AMD2:2020, 4.2. This document is not applicable to – equipment for the measurement of oxygen saturation of the haemoglobin in the micro vessels (capillaries, arterioles and venules), i.e. tissue oximeters. – frequency-domain and time-domain equipment for functional near-infrared spectroscopy. – equipment for the measurement of changes in the concentration of chromophores other than oxy- and deoxy-haemoglobin. – equipment for the measurement of changes in the concentration of oxy – and deoxy- haemoglobin in tissues other than the brain. This document does not specify the requirements for: – cerebral tissue oximeter equipment, which are given in ISO 80601 -2-85; and – pulse oximeter equipment, which are given in ISO 80601 -2-61.