The Weighing Equipment (Non-automatic Weighing Machines) Regulations 1988

(Regulation 9)

SCHEDULE 2 ACCURACY CLASSIFICATION OF NON-AUTOMATIC WEIGHING MACHINES

PART I GENERAL

1.  Non-automatic weighing machines are divided into four classes of accuracy according to specifications set out in Parts II to V of this Schedule. The division depends on their characteristics as well as the provisions relating to maximum capacity, the lower limit of the minimum load, the number of scale intervals and the scale interval itself.

2.  Where self and semi-self indicating machines are provided with an indicating device on which the last figure is clearly differentiated from the other figures, the classification of the machines into accuracy classes, their number of scale intervals and their minimum load shall be determined by reference to the verification scale interval.

3.  In each weighing mode of a machine each of the tare, weight indicating and printing devices operable in that mode has an associated verification scale interval. In a different weighing mode the same devices may have different verification scale intervals. When testing a machine it is therefore necessary to determine the verification scale interval for each device in each of the weighing modes in which it is operable.

4.  A weight indicating or printing device which, in any single weighing mode, has its weighing range divided into parts, each part having a different scale interval, will also have a different verification scale interval for each part. When testing in a particular weighing mode the relevant verification scale intervals are those associated with those devices in that mode.

5.  Each verification scale interval is—

(a) marked on the machine in accordance with the published particulars of the approved pattern or, if there are no such markings,

(b) specified in the relevant Table in Parts II to V.

6.  The presence of a tare device or of a verification device on the machine does not affect the classification of the machine, which depends on its own characteristics. These devices are considered as belonging to the class of accuracy of the machine to which they are attached irrespective of their own characteristics.

7.  For machines provided with several weight indicating or printing devices, each of the devices—

(a) has its own minimum load, the value of which is determined from the appropriate Table in Parts II, III, IV or V, depending on its metrological characteristics; and

(b) has the same digital scale interval, which must be at most equal to the smallest of any analogue scale interval.

8.  For machines provided with graduated tare devices the smallest scale interval of the devices must be equal to the smallest scale interval of the machine to which it is fitted.

The verification scale interval of these devices shall be equal to the smallest verification scale interval of the machine.

9.  For machines fitted with a graduated verification device the scale interval of such an incorporated device must be at most equal to one-fifth of the scale interval of the machine.

PART II MACHINES DESIGNATED CLASS I

10.  A machine made in accordance with an approved pattern and marked

in accordance with the published particulars of that pattern is a Class I machine.

11.  The specifications for non-graduated and graduated Class I machines are given in Table 1.

Table 1

Maximum capacity “Max”	Lower limit of the minimum load “Min”	Scale interval “d”	Number of scale intervals “n”	Verification scale interval “e”
Notes 1. When a machine is provided with a rider its verification scale interval shall be the smaller of the following— (i) the verification scale interval of the machine not taking into account the rider, or (ii) the scale interval of the rider device. 2. When graduated machines of the self and semi-self indicating type are provided with a device for interpolation of reading, this shall not be taken into account when determining the verification scale interval of the machine. 3. When graduated machines of the self or semi-self indicating type are provided with an indicating device on which the last figure is clearly differentiated from the other figures, the verification scale interval shall correspond to the last but one figure of the indication. 4. In the case of machines where the weight indicating or printing is in carat (metric) units or units of the imperial system the relevant capacity and verification scale interval shall be the amounts in carat (metric) or imperial units respectively which are equivalent to those specified in the Table in terms of mg, g and kg. 5. Where the equivalent metric value for an imperial scale interval falls between ranges then the value shall be considered as belonging to the lower range.
Non-graduated machines
100 mg ≤ Max ≤ 1 g	10 e			0.1 mg
1 g < Max < 10 g	50 e
10 g ≤ Max < 100 g	50 e			1 mg
100 g ≤ Max	50 e
Graduated machines
0.5 mg ≤ Max	d	d ≤ 0.005 mg	10 ≤ n	d
1 mg ≤ Max	10 d	0.01 mg ≤ d ≤ 0.05 mg	100 ≤ n	d
10 mg ≤ Max	50 d	0.1 mg ≤ d ≤ 0.5 mg	100 ≤ n	d
100 g ≤ Max	50 d	1 mg ≤ d	100 000 ≤ n	d

PART III MACHINES DESIGNATED CLASS II

12.  A machine which is:

(a) made in accordance with an approved pattern and marked

in accordance with the published particulars of that pattern, or

(b) first stamped before 1st November 1988 and marked “Class B” in accordance with the provisions for beam scales in the Weights and Measures Regulations 1963,

is a Class II machine.

13.  The specifications for non-graduated and graduated Class II machines are given in Table 2.

Table 2

Maximum capacity “Max”	Lower limit of the minimum load “Min”	Scale interval “d”	Number of scale intervals “n”	Verification scale interval “e”
Notes 1. When a machine is provided with a rider its verification scale interval shall be the smaller of the following— (a) the verification scale interval of the machine not taking into account the rider, or (b) the scale interval of the rider device. 2. When graduated self or semi-self indicating machines are provided with a device for interpolation of reading, this shall not be taken into account when determining the verification scale interval of the machine. 3. When graduated self or semi-self indicating machines are provided with an indicating device on which the last figure is clearly differentiated from the other figures, the verification scale interval shall correspond to the last but one figure of the indication. 4. Machines of a maximum capacity equal to or greater than 1 kg of an actual scale interval of 100 mg and of a verification scale interval of 1 g may belong to this class of machine, provided that the last figure is clearly differentiated from the other figures. 5. In the case of machines where the weight indicating or printing is in carat (metric) units or units of the imperial system the relevant capacity and verification scale interval shall be the amounts in carat (metric) or imperial units respectively which are equivalent to those specified in the Table in terms of mg, g and kg. 6. Where the equivalent metric value for an imperial scale interval falls between ranges then the value shall be considered as belonging to the lower range.
Non-graduated machines
1 g ≤ Max < 5 g	10 e
5 g ≤ Max < 100 g	10 e			5 mg
100 g ≤ Max < 200 g	10 e
200 g ≤ Max	50 e
Graduated machines
Non-self indicating machines
1 g ≤ Max < 50 g	10 d	1 mg ≤ d ≤ 5 mg	200 ≤ n < 50 000	d
10 g ≤ Max < 50 g	50 d	10 mg ≤ d ≤ 50 mg	1 000 ≤ n < 5 000	5 mg
50 g ≤ Max ≤ 500 g	10 d	1 mg ≤ d ≤ 5 mg	10 000 ≤ n ≤ 100 000	d
50 g ≤ Max < 5 kg	50 d	10 mg ≤ d ≤ 500 mg	1 000 ≤ n < 10 000
100 g ≤ Max ≤ 50 kg	50 d	10 mg ≤ d ≤ 500 mg	10 000 ≤ n ≤ 100 000	d
5 kg ≤ Max	50 d	1 g ≤ d	5 000 ≤ n < 10 000
10 kg ≤ Max	50 d	1 g ≤ d	10 000 ≤ n ≤ 100 000	d
Self and semi-self indicating machines
1 g ≤ Max ≤ 500 g	10 d	1 mg ≤ d ≤ 5 mg	200 ≤ n ≤ 100 000	d
10 g ≤ Max ≤ 50 kg	50 d	10 mg ≤ d ≤ 500 mg	1 000 ≤ n ≤ 100 000	d
5 kg ≤ Max	50 d	1 g ≤ d	5 000 ≤ n ≤ 100 000	d

PART IV MACHINES DESIGNATED CLASS III

14.  A machine which is—

(a) made in accordance with an approved pattern and marked

in accordance with the published particulars of that pattern, or

(b) first stamped before 1st November 1988 and marked “Class C” in accordance with the provisions for beam scales in the Weights and Measures Regulations 1963, or

(c) of a type referred to as “common form” and which was first stamped before 1st November 1988,

is a Class III machine.

15.  The specifications for non-graduated and graduated Class III machines are given in Table 3.

Table 3

Maximum capacity “Max”	Lower limit of the minimum load “Min”	Scale interval “d”	Number of scale intervals “n”	Verification scale interval “e”
Notes 1. In the case of machines where the weight indicating or printing is in units of the imperial system the relevant capacity and verification scale interval shall be the amounts in imperial units which are equivalent to those specified in the Table in terms of g, kg and t. 2. Where the equivalent metric value for an imperial scale interval falls between ranges then the value shall be considered as belonging to the lower range.
Non-graduated machines
20 g ≤ Max < 100 g	50 e			0.1 g
100 g ≤ Max < 1 kg	50 e
1 kg ≤ Max < 2 kg	50 e			1 g
2 kg ≤ Max	50 e
Graduated machines
Non-self indicating machines
20 g ≤ Max < 100 g	10 d	0.1 g ≤ d ≤ 0.2 g	200 ≤ n < 1 000	0.1 g
100 g ≤ Max < 1 kg	20 d	0.2 g ≤ d ≤ 1 g	200 ≤ n < 1 000
100 g ≤ Max ≤ 10 kg	20 d	0.1 g ≤ d ≤ 1 g	1 000 ≤ n ≤ 10 000	d
400 g ≤ Max < 5 kg	50 d	2 g ≤ d ≤ 5 g	200 ≤ n < 1 000
2 kg ≤ Max ≤ 50 kg	50 d	2 g ≤ d ≤ 5 g	1 000 ≤ n ≤ 10 000	d
5 kg ≤ Max < 10 t	50 d	10 g ≤ d ≤ 10 kg	500 ≤ n < 1 000
10 kg ≤ Max ≤ 100 t	50 d	10 g ≤ d ≤ 10 kg	1 000 ≤ n ≤ 10 000	d
15 t ≤ Max < 100 t	1 000 kg	20 kg ≤ d ≤ 100 kg	750 ≤ n < 1 000
20 t ≤ Max ≤ 1 000 t	1 000 kg	20 kg ≤ d ≤ 100 kg	1 000 ≤ n ≤ 10 000	d
150 t ≤ Max	10 d	200 kg ≤ d	750 ≤ n < 1 000
200 t ≤ Max	10 d	200 kg ≤ d	1 000 ≤ n ≤ 10 000	d
Self and semi-self indicating machines
20 g ≤ Max ≤ 10 kg	10 d	0.1 g ≤ d ≤ 1 g	50 ≤ n ≤ 10 000	d
400 g ≤ Max ≤ 50 kg	20 d	2 g ≤ d ≤ 5 g	200 ≤ n ≤ 10 000	d
5 kg ≤ Max ≤ 200 kg	20 d	10 g ≤ d ≤ 20 g	500 ≤ n ≤ 10 000	d
25 kg ≤ Max ≤ 100 t	50 d	50 g ≤ d ≤ 10 kg	500 ≤ n ≤ 10 000	d
15 t ≤ Max ≤ 1 000 t	1 000 kg	20 kg ≤ d ≤ 100 kg	750 ≤ n ≤ 10 000	d
150 t < Max	10 d	200 kg ≤ d	750 ≤ n ≤ 10 000	d

PART V MACHINES DESIGNATED CLASS IIII

16.  A machine which is—

(a) made in accordance with an approved pattern and marked

in accordance with the published particulars of that pattern, or

(b) first stamped before 1st November 1988 in accordance with the provisions for crane weighing machines constructed upon the hydraulic principle in the Weights and Measures Regulations 1963, or

(c) of the type referred to as “approximate weighers” and first stamped before 1st November 1988,

is a Class IIII machine.

17.  The specifications for non-graduated and graduated Class IIII machines are given in Table 4.

Table 4

Maximum capacity “Max”	Lower limit of the minimum load “Min”	Scale interval “d”	Number of scale intervals “n”	Verification scale interval “e”
Notes 1. In the case of machines where the weight indicating or printing is in units of the imperial system the relevant capacity and verification scale interval shall be the amounts in imperial units which are equivalent to those specified in the Table in terms of g, kg and t. 2. Where the equivalent metric value for an imperial scale interval falls between ranges then the value shall be considered as belonging to the lower range.
Non-graduated machines
1 kg ≤ Max < 2 kg	10 e			5 g
2 kg ≤ Max	10 e
Graduated machines
Non-self indicating machines
1 kg ≤ Max < 2 kg	10 d	5 g ≤ d ≤ 10 g	100 ≤ n < 400	5 g
2 kg ≤ Max < 4 t	10 d	10 g ≤ d ≤ 10 kg	100 ≤ n ≤ 400
2 kg ≤ Max ≤ 10 t	10 d	5 g ≤ d ≤ 10 kg	400 ≤ n ≤ 1 000	d
4 t ≤ Max	10 d	20 kg ≤ d	200 ≤ n < 400
8 t ≤ Max	10 d	20 kg ≤ d	400 ≤ n ≤ 1 000	d
Self and semi-self indicating machines
1 kg ≤ Max ≤ 10 t	10 d	5 g ≤ d ≤ 10 kg	100 ≤ n ≤ 1 000	d
4 t ≤ Max	10 d	20 kg ≤ d	200 ≤ n ≤ 1 000	d