Metrological requirements

The units of mass used shall be the legal units within the meaning of Council Directive 80/181/EEC of 20 December 1979 on the approximation of the laws of the Member States relating to units of measurement OJ L 39, 15.2.1980, p. 40. . Subject to compliance with this condition, the following units are permitted: SI units: kilogram, microgram, milligram, gram, tonne; imperial unit: troy ounce, if weighing precious metals; other non-SI unit: metric carat, if weighing precious stones. For instruments that make use of the imperial unit of mass referred to above, the relevant essential requirements specified below shall be converted to that unit, using simple interpolation. 2.1. The following accuracy classes have been defined: I special II high III medium IIII ordinary The specifications of these classes are given in Table 1. Table 1 Accuracy classes Class Verification scale interval (e) Minimum capacity (Min) Number of verification scale intervals n((Max)(e)) minimum value minimum value maximum value I 0,001 g ≤ e 100 e 50000 — II 0,001 g ≤ e ≤ 0,05 g 20 e 100 100000 0,1 g ≤ e 50 e 5000 100000 III 0,1 g ≤ e ≤ 2 g 20 e 100 10000 5 g ≤ e 20 e 500 10000 IIII 5 g ≤ e 10 e 100 1000 The minimum capacity is reduced to 5 e for instruments in classes II and III for determining a conveying tariff. The actual scale interval (d) and the verification scale interval (e) shall be in the form: 1 × 10^(k), 2 × 10^(k), or 5 × 10^(k) mass units, k being any integer or zero. For all instruments other than those with auxiliary indicating devices: d = e. For instruments with auxiliary indicating devices the following conditions apply: e1 10k g; d < e ≤ 10 d. Those conditions do not apply for instruments of class I with d < 10^(–4) g, for which e = 10^(–3) g. Instruments equipped with an auxiliary indicating device shall belong to class I or class II. For these instruments the minimum capacity lower limits for these two classes are obtained from Table 1 by replacement in column 3 of the verification scale interval (e) by the actual scale interval (d). If d < 10^(–4) g, the maximum capacity of class I may be less than 50000 e. Multiple weighing ranges are permitted, provided they are clearly indicated on the instrument. Each individual weighing range is classified according to point 3.1. If the weighing ranges fall into different accuracy classes the instrument shall comply with the severest of the requirements that apply for the accuracy classes in which the weighing ranges fall. Instruments with one weighing range may have several partial weighing ranges (multi-interval instruments). Multi-interval instruments shall not be equipped with an auxiliary indicating device. Each partial weighing range i of multi-interval instruments is defined by: — its verification scale interval e_(i) with e_((i + 1)) > e_(i) — its maximum capacity Max_(i) with Max_(r) = Max — its minimum capacity Min_(i) with Min_(i) = Max _((i – 1)) and Min_(1) = Min where: i= 1, 2, … r, i= partial weighing range number, r= the total number of partial weighing ranges. All capacities are capacities of net load, irrespective of the value of any tare used. The partial weighing ranges are classified according to Table 2. All partial weighing ranges shall fall into the same accuracy class, that class being the instrument’s accuracy class. Table 2 For i = r, the corresponding column of Table 1 applies, with e replaced by e_(r.) Multi-interval instruments i= 1, 2, … r i= partial weighing range number r= total number of partial weighing ranges Class Verification scale interval (e) Minimum capacity (Min) Number of verification scale intervals Minimum value Minimum value n((Max_(i))(e_((i 1)))) Maximum value n((Max_(i))(e_(i))) I 0,001 g ≤ e_(i) 100 e_(1) 50000 — II 0,001 g ≤ e_(i) ≤ 0,05 g 20 e_(1) 5000 100000 0,1 g ≤ e_(i) 50 e_(1) 5000 100000 III 0,1 g ≤ e_(i) 20 e_(1) 500 10000 IIII 5g ≤ e_(i) 10 e_(1) 50 1000 On implementation of the procedures laid down in Article 13, the error of indication shall not exceed the maximum permissible error of indication as shown in Table 3. In the case of digital indication the error of indication shall be corrected for the rounding error. The maximum permissible errors apply to the net value and tare value for all possible loads, excluding preset tare values. Table 3 Maximum permissible errors Load Maximum permissible error Class I Class II Class III Class IIII 0 ≤ m ≤ 50000 e 0 ≤ m ≤ 5000 e 0 ≤ m ≤ 500 e 0 ≤ m ≤ 50 e ± 0,5 e 50000 e < m ≤ 200000 e 5000 e < m ≤ 20000 e 500 e < m ≤ 2000 e 50 e < m ≤ 200 e ± 1,0 e 200000 e < m 20000 e < m ≤ 100000 e 2000 e < m ≤ 10000 e 200 e < m ≤ 1000 e ± 1,5 e The maximum permissible errors in service are twice the maximum permissible errors fixed in Section 4.1. 5. Weighing results of an instrument shall be repeatable, and shall be reproducible by the other indicating devices used and in accordance with other methods of balancing used. The weighing results shall be sufficiently insensitive to changes in the position of the load on the load receptor. 6. The instrument shall react to small variations in the load. Instruments of classes II, III and IIII, liable to be used in a tilted position, shall be sufficiently insensitive to the degree of tilting that can occur in normal use. The instruments shall meet the metrological requirements within the temperature range specified by the manufacturer. The value of this range shall be at least equal to: 5 °C for an instrument in class I; 15 °C for an instrument in class II; 30 °C for an instrument in class III or IIII. In the absence of a manufacturer’s specification, the temperature range of – 10 °C to + 40 °C applies. Instruments operated from a mains power supply shall meet the metrological requirements under conditions of power supply within the limits of normal fluctuation. Instruments operated from battery power shall indicate whenever the voltage drops below the minimum required value and shall under those circumstances either continue to function correctly or be automatically put out of service. Electronic instruments, except those in class I and in class II if e is less than 1 g, shall meet the metrological requirements under conditions of high relative humidity at the upper limit of their temperature range. Loading an instrument in class II, III or IIII for a prolonged period of time shall have a negligible influence on the indication at load or on the zero indication immediately after removal of the load. Under other conditions the instruments shall either continue to function correctly or be automatically put out of service.

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Source: EUR-Lex (Cellar) · retrieved 2026-11-05 · Text as adopted (Official Journal); later amendments are not incorporated in this text.