SuitabilityU.K.
9.—(1) A meter measuring system shall have no feature likely to facilitate fraudulent use, whereas possibilities for unintentional misuse shall be minimal.
(2) A meter measuring system shall be suitable for its intended use taking account of the practical working conditions and shall not require unreasonable demands of the user in order to obtain a correct measurement result.
(3) Where a measuring system is designed for the measurement of values of the measurand that are constant over time, the instrument shall be insensitive to small fluctuations of the value of the measurand, or shall take appropriate action.
(4) A meter measuring system shall be robust and its materials of construction shall be suitable for the conditions in which it is intended to be used.
(5) A meter measuring system shall be designed so as to allow the control of the measuring tasks after the instrument has been placed on the market and put into use. If necessary, special equipment or software for this control shall be part of the instrument. The test procedure shall be described in the operation manual.
(6) When an instrument has associated software which provides other functions besides the measuring function, the software that is critical for the metrological characteristics shall be identifiable and shall not be inadmissibly influenced by the associated software.
(7) For any measured quantity relating to the same measurement, the indications provided by various devices shall not deviate one from another by more than one scale interval where devices have the same scale interval. In the case where the devices have different scale intervals, the deviation shall not be more than that of the greatest scale interval.
(8) It shall not be possible to divert the measured quantity in normal conditions of use unless it is readily apparent.
(9) Any percentage of air or gas not easily detectable in the liquid fuel shall not lead to a variation of error greater than—
(a)0.5 % for liquid fuel of a viscosity not exceeding 1 mPa.s; or
(b)1 % for liquid fuel of a viscosity exceeding 1 mPa.s,
but the allowed variation shall never be smaller than 1% of the minimum measured quantity. This value applies in the case of air or gas pockets.
(10) Instruments for direct sales—
(a)A meter measuring system for direct sales shall be provided with means for resetting the display to zero.
(b)It shall not be possible to divert the measured quantity.
(c)The display of the quantity on which the transaction is based shall be permanent until all parties in the transaction have accepted the measurement result.
(d)Meter measuring systems for direct sales shall be interruptible.
(e)Any percentage of air or gas in the liquid fuel shall not lead to a variation of error greater than the values specified in sub-paragraph (9).