Legal Metrology Section


Inspectors must be able to apply relevant metrological legislation in accordance with local administrative procedures and with reference to national, European and international guidance. They should be able to link metrology law to other relevant consumer legislation and operate in the light of the strategies of metrological institutions. They must be able to test and verify individual types of weighing and measuring equipment as required by their role, using suitable data processing equipment and drawing on their understanding of traceability and their knowledge of mathematics, statistics and physics, particularly in relation to uncertainties of measurement. They should be able to work with regard to national frameworks for quality management, accreditation, certification and verification.

Core Learning Resources


International Organisation of Legal Metrology (OIML)

These are model regulations specifying the metrological characteristics of measuring instruments and methods and equipment for checking their conformity. Inspectors will need to refer to them as required by their role and the expectations of their enforcing authority, but some are generally applicable and are listed below.

See in particular:

  • R24 Standard one metre bar for verification officers, 1975
  • R34 Accuracy classes of measuring instruments, 1979
  • R35 Material measures of length for general use, 2007
  • R40 Standard graduated pipettes for verification officers, 1981
  • R41 Standard burettes for verification officers, 1981
  • R42 Metal stamps for verification officers, 1981
  • R43 Standard graduated glass flasks for verification officers, 1981
  • R47, Standard weights for testing of high capacity weighing machines, 1979
  • R49 Water meters for cold potable water and hot water, 2013
  • R50 Continuous totalizing automatic weighing instruments (belt weighers), 2014
  • R51 Automatic catchweighing instruments, 2006
  • R52 Hexagonal weights – Metrological and technical requirements, 2004
  • R60 Metrological regulation for load cells, 2000
  • R61 Automatic gravimetric filling instruments, 2004
  • R76 Non-automatic weighing instruments, 2006
  • R79 Labelling requirements for prepackages, 2015
  • R87 Quantity of product in prepackages, 2004
  • R98 High-precision line measures of length, 1991
  • R106 Automatic rail-weighbridges, 2011
  • R107 Discontinuous totalizing automatic weighing instruments (totalizing hopper weighers), 2007
  • R111 Weights of classes E1, E2, F1, F2, M1, M1-2, M2, M2-3 and M3, 2004
  • R117 Dynamic measuring systems for liquids other than water, 2007
  • R138 Vessels for commercial transactions, 2007


British Standards Institution (BSI)

See in particular:

  • BS EN ISO 9000:2015 – Quality management systems: fundamentals and vocabulary
  • BS EN ISO 9001:2015 – Quality management systems: requirements
  • BS EN ISO/IEC 17025:2017 – General requirements for the competence of testing and calibration laboratories
  • BS EN ISO/IEC 17020:2012 – Conformity assessment: requirements for the operation of various types of bodies performing inspection
  • BS EN ISO/IEC 17065:2012– Conformity assessment: requirements for bodies certifying products, processes and services
  • BS EN 45501:2015 – Metrological aspects of non-automatic weighing machines

 Directive 2014/31/EU Non-automatic weighing instruments

 Directive 2014/32/EU Measuring instruments

Both Europa

 Enforcement of the Weights and Measures Act 1985

Office for Product Safety and Standards (OPSS), 2018

Includes guidance on completing section 70 returns and specifications for weights and measures

 Weights and measures regulations guidance

OPSS, 2016

Guidance for inspectors and manufacturers of weights and measures equipment

 Packaged goods: weights and measures regulations

OPSS, 2015

Includes guidance for business on the Weights and Measures (Packaged Goods) Regulations 2006

 Notified bodies: appointment and co-ordination

 Approved verification: guidance, application form and stickers

Both OPSS, 2017

Includes the local authority notified body protocol

 Enhanced consumer measures: guidance for enforcers of consumer law

Department for Business, Energy & Industrial Strategy (BEIS), 2015

 Consumer Rights Act 2015

BEIS, 2015

Policy paper describing what the Act aims to achieve

 Consumer protection from unfair trading

 Business to business marketing

 Price marking of goods for retail sale

All Business Companion

Background on the Consumer Protection from Unfair Trading Regulations 2008, the Business Protection from Misleading Marketing Regulations 2008 and the Price Marking Order 2004

 Weights and Measures Act 1985

 Consumer Rights Act 2015

 Deregulation (Weights and Measure) Order 1999

 Legislative Reform (Verification of Weighing and Measuring Equipment) Order 2008


Training Courses

 Training Services

United Kingdom Accreditation Service (UKAS)

 E-Learning College

Chartered Trading Standards Institute (CTSI)

 Training Courses

National Physical Laboratory (NPL)

 Training Services

National Measurement & Regulation Office (NMRO)

Further Reading



These give advice on harmonising and improving legal metrology work.

See in particular:

  • D2 Legal units of measurement, 2007
  • D14 Training and qualification of legal metrology personnel, 2004
  • D23 Principles for metrological control of equipment used in verification, 1993
  • D31 General requirements for software controlled measuring instruments, 2008



These give guidelines for the application of certain requirements to legal metrology.

See in particular:

  • G7 Guide to calibration, 1989
  • G10 Verification equipment for national Metrology Services, 1986
  • G14 Density measurement, 2011


European Cooperation in Legal Metrology (WELMEC)

These give advice for manufacturers and notified bodies on what the organisation considers as best practice.

See in particular:

  • 2 Series (2, 2.1 through to 2.8) for weighing instruments
  • 5.2 Market surveillance guide (NAWI and MID), 2015
  • 7.2 Software guide (MID 2014/32/EU), 2015
  • 8.0 Directives 2014/31/EU and 2014/32/EU: assessment and operation, 2016
  • 8.21 Guidance to the application of the MID 2004/22/EC, 2012
  • Links to other member states for access to TECs issued in those countries

 Guide to the expression of uncertainty in measurement

International Bureau of Weights and Measures (BIPM), 2008

 The expression of uncertainty and confidence in measurement

UKAS, 2012

 The ‘Blue Guide’ on the implementation of EU product rules

European Commission, 2016

 Measurement Good Practice Guides

  Metrology for the 2020s

Both NPL

Other Information

 International vocabulary of legal metrology


 Code of Practice: Calibration of Non-Automatic Weighing Instruments

UK Weighing Federation (UKWF), 2016

The national trade association for manufacturers, system integrators, distributors, repairers, installers and service organisations involved in the weighing industry

 Local Government Legal Metrology Expert Panel

Knowledgehub (subscription required)

Supports coordination in matters of strategy, policy and operational practice within UK legal metrology, offering specialist and expert advice to all members of the UK legal metrology community