# The Weights and Measures (Local and Working Standard Weights and Testing Equipment) Regulations 1986

S.I. 1986/1685 · made 29 September 1986

These Regulations replace the Weights and Measures (Local and Working Standard Weights and Testing Equipment) Regulations 1983. They prescribe the methods of testing and adjusting, and the limits of error for, working standard weights and certain testing equipment used for weighing by inspectors of weights and measures. They also make provision for limits of error for local standard weights and for the period of validity of certificates of fitness of those local standards.

PDFs: Printed copy https://openlegislation.uk/weights-and-measures-local-and-working-standard-weights-and-testing-equipment-regulations-1986/pdf/uksi_19861685_en.pdf

## Introductory text

WEIGHTS AND MEASURES
Made 29th September 1986
Laid before Parliament 9th October 1986
Coming into Operation 1st November 1986
The Secretary of State, in exercise of powers conferred on him by sections 4(5) and (6), 5(9), 86(1) and 94(1) of the Weights and Measures Act 1985 (hereinafter referred to as “the Act”) and of all other powers enabling him in that behalf, hereby makes the following Regulations:—

## Citation, commencement and revocation

## 1 

(1) These Regulations may be cited as the Weights and Measures (Local and Working Standard Weights and Testing Equipment) Regulations 1986 and shall come into operation on 1st November 1986.
(2) The Weights and Measures (Local and Working Standard Weights and Testing Equipment) Regulations 1983 are hereby revoked.

## Interpretation

## 2 

(1) In these Regulations—
“analogue” means capable of assigning any value or position within a continuous range;
“digital” means capable of assigning only certain discrete values or positions within a continuous range by a series of discontinuous steps;
“discrimination threshold” means, in the case of testing equipment with a digital indicator, the weight which produces a change of reading of one digit from one change point to the next change point, and in the case of testing equipment with an analogue indicator, the weight which produces a 1 millimetre apparent movement of the pointer;
“non-automatic weighing machine” means a machine which requires the intervention of an operator during the weighing process, especially to deposit loads on, or remove loads from, the part of the machine on which loads are placed for the purpose of their being weighed and to determine the result of the weighing process;
“repeatability” means the ability of weighing equipment to indicate, under defined conditions of use, closely similar quantities on repeated weighings; and
“95 per cent. confidence interval” means the range of values within which the true value may be expected to lie with a 0.95 level of probability.
(2) The symbols for, and abbreviations of, units of weight used in these Regulations refer to the relevant units set out in Schedule 1 to these Regulations.

## Testing

## 3 

(1) Working standard weights and test weights and egg grading machine test poises shall have been tested within twelve months before use and, where an inspector has reasonable cause to believe that any such weight or poise is not accurate within the relevant limit of error, he shall test it before use.
(2) Where a test reveals an error exceeding the relevant limit of error the weight or poise shall not be further used until it has been so adjusted that any error is within that limit.

## 4 

Working standard weights shall be tested against local standard weights by the method of substitution.

## 5 

Test weights and egg grading machine test poises shall be tested by either:
(a) the method of substitution, or
(b) the method of comparison against either:
(i) local standard weights; or
(ii) working standard weights or test weights,
provided that in the opinion of the inspector the necessary accuracy can be achieved.

## 6 

(1) Testing equipment consisting of weighing equipment shall have been tested for repeatability and for discrimination threshold within six months before use and shall not be used for testing working standard weights, test weights or egg grading machine test poises unless it complies with the requirements of Regulation 7 below.
(2) Where an inspector has reasonable cause to believe that any testing equipment referred to in this Regulation is not accurate within the relevant limit of error, he shall test it before use.

## Testing Equipment

## 7 

Testing equipment consisting of weighing equipment used for testing working standard weights, test weights and egg grading machine test poises shall comply with the following requirements:
(a) the discrimination threshold of the testing equipment used shall not exceed one-fifth of the relevant amount specified in Tables 1 to 6 in Schedule 2 to these Regulations as the limit of error for the weight being tested, or, in the case of an egg grading machine test poise, 7 mg, and
(b) the repeatability of the testing equipment shall be such that the 95 per cent. confidence interval of a single reading does not exceed one-fifth of the relevant amount specified in Tables 1 to 6 in Schedule 2 to these Regulations as the limit of error for the weight being tested, or, in the case of an egg grading machine test poise, 7 mg.

## Prescribed limits of error

## 8 

(1) The prescribed limits of error relating to local and working standard weights and test weights shall be those set out in Tables 1 to 6 in Schedule 2 to these Regulations.
(2) The prescribed limit of error relating to egg grading machine test poises shall be 35 mg.

## Period of validity of certificates of fitness of local standards

## 9 

The period of five years is hereby prescribed in the case of a weight for the purpose of section 4(6) of the Act (which relates to periods of validity of certificates of fitness of local standards) running from the date of issue of the certificate.

## Signature

Michael Howard
Parliamentary Under-Secretary of State
Department of Trade and Industry
29th September 1986

## Schedule 1 

Symbols and abbreviations of units of weight
Imperial
Metric
pound
lb
kilogram
kg
ounce
oz
gram
g
milligram
mg
carat (metric)
C.M.

## Schedule 2 

TABLE 1
IMPERIAL SYSTEM Avoirdupois weights
Limit of error in milligrams
Local or working standards of—
Local standard
Working standard
56 lb
400
1250
28 lb
200
650
14 lb
100
320
7 lb
50
160
4 lb
30
90
2 lb
15
45
1 lb
7
20
8 oz
3
10
4 oz
2
6
2 oz
1
3
1 oz
0.8
2.5
1/2 oz
0.7
2
1/4 oz
0.5
1.5
1/8 oz
0.5
1.5
1/16 oz
0.4
1.2
1/32 oz
0.3
1
50 lb
350
1100
20 lb
150
450
10 lb
70
220
5 lb
35
110
TABLE 2
Weights expressed as multiples or fractions of 1/7000 lb
Local standard of—
Limit of error in milligrams
100
0.53
50
0.44
30
0.40
20
0.33
10
0.27
5
0.22
3
0.20
2
0.17
1
0.13
0.5
0.11
0.3
0.10
0.2
0.09
0.1
0.06
0.05
0.06
0.03
0.06
0.02
0.06
0.01
0.06
TABLE 3
Troy weights
Local standard of ounces troy—
Limit of error in milligrams
500
250
400
200
300
150
200
100
100
50
50
25
40
20
30
15
20
10
10
5
5
2.5
4
2.0
3
1.5
2
1.0
1
1.0
0.5
0.7
0.4
0.6
0.3
0.6
0.2
0.5
0.1
0.4
0.05
0.4
0.04
0.3
0.03
0.3
0.025
0.3
0.02
0.25
0.01
0.22
0.005
0.18
0.004
0.16
0.003
0.15
0.002
0.13
0.001
0.11
TABLE 4
METRIC SYSTEM Metric weights other than carat (metric) weights
Limit of error in milligrams
Local or working standards of—
Local standard
Working standard
20 kg
300
1000
10 kg
150
500
5 kg
75
250
2 kg
30
100
1 kg
15
50
500 g
7.5
25
200 g
3.0
10
100 g
1.5
5
50 g
1.0
3
20 g
0.8
2.5
15 g
0.7
2.2
10 g
0.6
2.0
5 g
0.5
1.5
4 g
0.5
1.5
3 g
0.4
1.2
2 g
0.4
1.2
1 g
0.3
1.0
500 mg
0.25
0.8
400 mg
0.25
0.8
300 mg
0.25
0.8
200 mg
0.20
0.6
150 mg
0.20
0.6
100 mg
0.15
0.5
50 mg
0.12
0.4
20 mg
0.10
0.3
10 mg
0.08
0.25
5 mg
0.06
0.20
2 mg
0.06
0.20
1 mg
0.06
0.20
TABLE 5
Carat (metric) weights
Local standard of— C.M.
Limit of error in milligrams
500
1.5
200
0.93
100
0.80
50
0.60
20
0.47
10
0.40
5
0.30
2
0.23
1
0.20
0.5
0.15
0.25
0.12
0.20
0.11
0.10
0.10
0.05
0.08
0.02
0.06
0.01
0.06
TABLE 6
Test weights
Imperial weight
Limit of error
Metric weight
Limit of error
11200 lb
500 g
4480 lb
200 g
5000 kg
500 g
2240 lb
100 g
2000 kg
200 g
1120 lb
50 g
1000 kg
100 g
1008 lb
50 g
500 kg
50 g
560 lb
20 g
250 kg
20 g
448 lb
20 g
200 kg
20 g
224 lb
10 g
100 kg
10 g
112 lb
5 g
50 kg
5 g

## Explanatory note

These Regulations replace the Weights and Measures (Local and Working Standard Weights and Testing Equipment) Regulations 1983. They prescribe the methods of testing and adjusting, and the limits of error for, working standard weights and certain testing equipment used for weighing by inspectors of weights and measures. They also make provision for limits of error for local standard weights and for the period of validity of certificates of fitness of those local standards.
The Regulations make the following changes of substance:
(a) test weights may be tested by either the method of substitution or the method of comparison (previously by substitution only) (Regulation 5);
(b) testing equipment consisting of weighing machines shall be tested for repeatability and for discrimination threshold within six months before use (previously 12 months) (Regulation 6);
(c) the requirements for testing equipment consisting of weighing machines have been changed so that the inspector has a wider choice, provided requirements as to repeatability and discrimination threshold are met (previously the minimum sensitiveness for balances, beamscales and platform machines was prescribed) (Regulation 7); and
(d) the prescribed limits of error for test weights in excess of 56 lb or 20 kg are doubled (Regulation 8 and Schedule 2, Table 6).

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Source: https://www.legislation.gov.uk/uksi/1986/1685 (the official version)
Page: https://openlegislation.uk/weights-and-measures-local-and-working-standard-weights-and-testing-equipment-regulations-1986
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.