We have seen some inconsistencies in acoustic noise measurements for TCO Certified Notebooks 5.0, TCO Certified All-in-one PCs 4.0 and TCO Certified Desktops 5.0.
Therefore, we will include the following clarification (in red) in our next generation of TCO Certified. We are already using this principle:
A.4.1 (For Notebooks) A.4.3( For AIO and Desktop) Acoustic noise
To be able to provide information about acoustic noise levels that permits comparison between different Notebook computers the declared A-weighted sound power level (LWAd) in operating and idling mode shall be measured in accordance with ISO 7779:2010 and reported in accordance with ISO 9296 p.4.4.1 in bels (B). As these standards do not include any clear definition of operating and idling mode, the following definitions appy for these modes and for the declared sound values:
Sound power level (LW):
Total emitted sound power from a sound source, given in bels (B) and with the reference 1 pW.
The measured linear sound level (sound pressure or sound power) weighted against the sensitivity of the human ear for different frequencies (A-curve).
Declared A-weighted sound power level (LWAd): in bels (B). Defined in accordance with ISO 9296 3.2.5.
Operating mode. A condition in which the system and hard disk drive shall be operated, at a load equal to or higher than “operating mode” for personal computers and workstations, as defined in ECMA-74.
Idling mode. A condition in which the system shall be operated, at a load equal to or higher than “idling mode” for personal computers and workstations, as defined in ECMA-74.
For Notebook, Desktop and All-in-on applications we will from now on require that the measured idling mode and operating mode levels are declared on the emissions Verification of Conformity. If applying through our online application system, we request that you report the worst case sound level, which in most cases will be “operating mode”.