Dr Takashi Usuda CCAUV and CCPR President CIPM Member Report to the CCU meeting 2016 from Consultative Committee for Acoustics, Vibration and Ultrasound (CCAUV) and Consultative Committee for Photometry and Radiometry (CCPR) Dr Takashi Usuda CCAUV and CCPR President CIPM Member

CCAUV 17 members and 2 liaisons (ISO and IEC) Related units Pa (bel, neper) in acoustics associated its frequency Hz m/s2 as acceleration in vibration associated its frequency Hz W as ultrasonic power associated its frequency Hz Agreements and recommendations in the past meetings bel and neper be kept as “non SI units” the statement that the reference value of the quantity should always be stated in SI units whenever the decibel is used encourage the use of the SI in preference to the decibel (while it　would be extremely difficult to change long-standing habits relating to the use of the dB)

CCPR (1) 23 members and 2 liaisons (CIE and WMO) Related units luminous flux (lm) Illuminance (lx) detector based metrology Luminous intensity (cd) source based metrology Luminance (cd/m2) source based metrology Agreements and recommendations in the past meetings A change from Candela to Lumen has no real practical benefit, in contrary, the geometrical aspects of photometry becomes hidden. In the absence of compelling reasons to change from the candela to the lumen as the base SI unit, it is highly recommended to maintain the status quo.

CCPR (2) In 2015 the CCPR finalized the “Mise en pratique for the definition of the candela and associated derived units for photometric and radiometric quantities in the International System of Units (SI)”. The CIPM welcomed the document at its 104th meeting in 2015 (Decision CIPM/104-45) The document is now available as an open access document in SI section of the BIPM HP http://www.bipm.org/utils/en/pdf/SIApp2_cd_en.pdf A joint WG of CCPR and CIE is preparing a more extensive publication “Principles Governing Photometry”

CCAUV and CCPR Both CCs deal with physiological quantities. No special requests or opinions to include description of physiological quantities in the next version of SI Brochure from both CCs. In conclusion Related contents in the 9th SI Brochure draft are fully consistent with our agreements and recommendations. Note New units on non-visual effects of light are invented (relating to the specified human photopigment, …) in CEN Draft Standard (2014). This will be monitored and discussed at CCPR.