Certification and calibration of weighing and measuring instruments including quality management systems

Application forms, services available and guidance information.


Testing, accreditation and calibration

NMO Certification and Technical Services, which is part of the Office for Product Safety and Standards (OPS&S), operates as a notified body providing a range of conformity assessment procedures (PDF, 113KB, 1 page) activities under the European Non-Automatic Weighing Instruments (NAWI) Directive 2009/23/EC and the European Measuring Instruments Directive (MID) 2004/22/EC. We also provide training courses and international consultancy services in support of national and international competency and capability requirements.

Under the New Legislative Framework (NLF) new versions of the European Directives have been published: 2014/31/EU for NAWI and 2014/32/EU for MID which came into force on 20 April 2016.

NMO is responsible for the national type approval of certain instruments regulated by UK weights and measures legislation, is an Issuing Authority for certification of instruments conforming to certain International Organisation of Legal Metrology (OIML) International Recommendations, and is an Issuing Participant under the OIML Mutual Acceptance Arrangement.

In addition to the conformity assessment activities under NAWI and MID, NMO is an accredited certification body for certifying International Standards Organisation (ISO) 9001:2008 Quality Management Systems and assessing the quality management systems under the Deregulation (Weights and Measures) Order 1999 (SI 1999 No 503).

The weighing and measuring instruments that we can certify range from precision balances and supermarket scales to railway weighbridges, beer glasses to fuel dispensers, and taximeters to utility meters.

Access the EC Type examination and management systems declarations of conformity (PDF, 247KB, 2 pages) to see the full list of NAWI and MID instruments, and their respective conformity assessments, for which we are authorised to issue certificates.

These services are available to manufacturers, installers and repairers to enable them to legally place weighing and measuring instruments, that are used in legally controlled applications, on to the European and UK market.

Access the Guide to Certification Services (PDF, 774KB, 58 pages) to see what we provide, including additional information relating to type examination / approval and management system certification.

Read on to find out more about the NMO services for product certification and quality management systems, or please contact:

Head of Technical Services

Mannie Panesar
Office for Product Safety and Standards
Stanton Avenue

TW11 0JZ

Health and Safety

OPS&S recognises that the work of NMO services contains hazards relating to its laboratory based activities and for that reason, OPS&S is committed to achieving certification of our approach to managing those hazards through the British Standard for Occupational Health and Safety 18001 Management System. Please read NMO's health and safety policy and objectives (PDF, 32.3KB, 1 page) .

Product certification (type examination/approval)

Organisations wishing to get the design of their instrument certified, in accordance with MID, NAWI, OIML or UK regulations, will need to have their product conformity assessed.

To receive a quotation or make an application for assessment and certification of your weighing or measuring instrument please apply online for type examination/approval of your weighing or measuring instrument and someone will respond to you quickly.

Management system certification

Organisations that wish to conduct the conformity assessment of a weighing or measuring instrument with the relevant modules making up the procedures as described in annexes A to H1 in accordance with MID, or annex II, 2 for NAWI or to self verify or re-verify under UK regulations must be certified to do so.

NMO offers certification to the following relevant standards and regulations:

  • quality management systems to ISO 9001
  • declaration of type conformity (guarantee of production quality) to NAWI
  • manufacturers declaration of conformity to MID
  • management system certification for self verifiers under section 11a of the Weights and Measures Act

To make an enquiry regarding certification in these areas please email the NMO ACB.

To receive a quotation, or if you require any of the certifications listed above, please apply online for management system certification and someone will respond to you quickly.

You can also apply online to request an Changes to ACB certification including extension of scope (MS Word Document, 581KB) , or to amend your current NMO authorisation or for any other change(s) to your registration, eg change of address. Please download the application form, enter the details into the relevant areas using a text editor (eg MS Word etc), and then email the completed application form, as a text document, to the NMO ACB.

NMO clients who have been certified to ISO 9001 are permitted to use the NMO certification mark to demonstrate this achievement. For further information about the marks and the restrictions for use, access certification marks and restrictions of use (MS Word Document, 6.05MB) .


Organisations that are unsure if their product or management system will satisfy the requirements for certification may find benefit in a pre-assessment.

Should you wish to discuss the benefits of a pre-assessment, please email to certification services.

To get a quote please apply online for pre-assessment. You can also use the on line application if you are unsure if your instrument will satisfy the requirements for certification, or to use the NMO pre-assessment service prior to submitting an application for certification.

Information on the scopes of all certifications offered by NMO (type examination/approval and management systems).

See which instruments are included in the scope of :

Certificates issued by NMO

Access copies of the following certificates:

UK national type approval certificates

EEC type examination certificates

NAWI type examination certificates (2009/23/EC and 2014/31/EU

MID type examination certificates(2004/22/EC and 2014/32/EU)

Several old approach directives were revoked under the MID. EEC certificates, which have been issued under these old approach directives, continue to be valid until their date of expiry but cannot be renewed. These certificates continue to apply to instruments that have been verified and are in use.

Useful information, guidance and FAQs

Information on the MID and the instruments covered

Read information relating to

MID and type examination (PDF, 229KB, 3 pages) to assist you when considering making an application

Water meters (PDF, 182KB, 2 pages)

Gas meter and volume conversion devices (PDF, 210KB, 3 pages)

Active electrical energy meters (PDF, 248KB, 3 pages)

Heat meters (PDF, 163KB, 1 page)

Liquids other than water (PDF, 235KB, 3 pages)

Automatic weighing instruments (PDF, 287KB, 3 pages)

Taximeters (PDF, 139KB, 2 pages)

Material measures of length (PDF, 370KB, 2 pages)

Dimensional measuring instrument (PDF, 229KB, 2 pages)

Information on non-automatic weighing instruments

Read information relating to Non-automatic weighing instruments (PDF, 236KB, 2 pages) to assist you if you are considering making an application.

Information on OIML approvals

Access information from the OIML web site on the Basic Certificate System and MAA certificates under the OIML Mutual Acceptance Arrangement (OIML MAA).

Approval certificates are registered with the OIML and published on the OIML web site Registered OIML Certificates and can be accessed by completing the search/selection criteria.

Information on UK national approvals

Read information relating to:

Intoxicating liquor measuring equipment (PDF, 150KB, 1 page)

Cubic measures (PDF, 121KB, 1 page)

Dynamic axle weighers road vehicles (PDF, 193KB, 1 page)


The Non-Automatic Weighing Instruments (NAWI) Directive (2009/23/EC)

The Measuring Instruments Directive (MID) (2004/22/EC)

The Gas Act

The Electricity Act 1989 (Schedule 7)

CE symbol and proportional sizing

Read a copy of the requirements relating to the CE symbol CE mark and proportional sizing (PDF, 1.24MB, 1 page) , as defined the MID Article 17 Markings, which shall be in accordance to the design laid down in paragraph I.B(d) of the Annex to Decision 93/465/EEC.

Frequently asked questions

Access information from Frequently asked questions (PDF, 322KB, 2 pages)

International agreements

NMO has bilateral agreements with approval bodies in China, Australia and New Zealand. These agreements support manufacturers who wish to gain approval in those countries and vice-versa. These agreements are available to download:

Australia mutual recognition agreement (PDF, 31.5KB, 5 pages) (MRA) between NMO and Australia

China- mutual acceptance agreement (PDF, 124KB, 5 pages) (MAA) between NMO and China

Impartiality committee

Access information about the role of NMO Impartiality committee (PDF, 173KB, 1 page) .

Complaints and appeals

NMO operates complaints and appeals procedures.

Access information about how to make a complaint (PDF, 68.9KB, 1 page) .

Access information about how to make an appeal (PDF, 95.8KB, 1 page) .

Calibration and testing of weighing and measuring equipment

NMO technical services also provide a calibration and testing service for local authorities and businesses working with weighing and measuring equipment. Read on to find out more about this service or contact:

Head of Technical Services

Mannie Panesar
Office for Product Safety and Standards
Stanton Avenue

TW11 0JZ

Published 2 April 2014
Last updated 1 December 2017 + show all updates
  1. Video added introducing NMO Certification and Technical Services.
  2. The document "A guide to NMRO Certification Services" has been updated to revision 2 and is now called "A guide to NMO Certification Services" dated (27 July 2017).
  3. Addition of a guidance publication relating to the activities of the NMRO Certification Services, and link to weights and measures technical updates.
  4. Addition of information regarding the complaints and appeals processes
  5. Amended to include information on management system certification marks and restrictions of use.
  6. This Guide has been updated to include a link to Legal metrology training: support of national competency for UK trading standards officers, and international consultancy services
  7. First published.