Legal Metrology

NSAI; National Metrology Laboratory

Measurement functions at National Standards Authority of Ireland (NSAI) are split across two divisions within NSAI; Legal Metrology and National Metrology Laboratory.

The National Metrology Laboratory maintains, establishes, and develops the Irish National Measurement Standards for physical quantities.  It maintains standards in the area of electricity, frequency, length, acoustics, mass, pressure, force, temperature, humidity and torque.

The National Metrology Laboratory issues calibration certificates approved for International Standards under the CIPM (International Committee for Weights and Measures) (CIPM) Mutual Recognition Arrangement (MRA).  These calibration certificates are recognised by equivalent authorities worldwide.

The National Metrology Lab is a member of the European Association of National Metrology Institutions (EURAMET). The National Standards maintained by NML and the calibration certificates issued are approved under the CIPM MRA. NSAI NML is also certified to ISO9001. Calibration certificates issued under the CIPM MRA are fully recognised and accepted by accreditation bodies and regulatory authorities worldwide.


The Legal Metrology Service enforces the legal metrology and packaging legislation. The Legal Metrology Service has powers to inspect premises and test instruments to verify compliance with the Legal Metrology Act and the Packaged Goods (Quantity Control) Act.

Their inspectors visit several thousand premises annually and inspect over ten thousand instruments. The Service takes a risk-based approach to enforcement.  It undertakes a targeted inspection campaigns.  It undertakes prosecutions.

The Legal Metrology Service undertakes the EU verification program.  This is undertaken across a range of sectors including small and large retailers, public houses, large industrial weighing machines, vehicle weighbridges, animal weighing, forecourt dispensers, petrol and diesel dispensers, taximeters, road tanker systems, milk metres, and capacity measures in licensed premises and others.

The NSAI operates an authorised verifier scheme by which third-party operators may be authorised to carry out verification.  They may be authorised in respect of particular categories of instrument.

Measuring Instruments

Measuring instruments in trade use are regulated to ensure compliance and performance with and the relevant standards.  This is in order to ensure public confidence.

The NSAI undertakes testing and certification through an examination process.  This leads to the issue of a type approval certificate or design approval certificate.  This is required before a manufacturer may sell instruments to a trader.  Each instrument must be checked in terms of the relevant performance criteria.  This is “verification”.

Manufacturers of measuring and weighing equipment and instruments must apply for the required type-approval certificate or design approval certificate under the Non-Automatic Weighing Instruments Directive or the Measuring Instruments Directive.  They may apply to any authority in the EU.

The CE mark is applied to instruments to show that they comply with the requirements of the EU directive.  Non-automatic weighing machines must be marked with a green ‘M’, other measuring instruments are marked with an ‘M’ in a box.

Measuring Equipment Standards

The technical and metrological standards are described in technical terms in the EU legislation and supporting documents.  In the case of modern “new” approach directives, the specifications are not described in the legislation to the same extent.  European standards or OIML recommendations may be followed. The EU standard must adopt the requirements of the directive in respect of the instruments covered.

In principle, national laws may deal with other issues and measuring instruments not covered by the EU legislation.  However, when a State plans to introduce a national law, it must inform the EU Commission. The Commission keeps an online database of such regulations.

Verifying & Testing Measuring Equipment

Suppliers and traders must ensure that measuring instruments are verified before being put in trade use. Traders have a duty to ensure that measuring instruments work properly and are kept in good condition.  This entails a duty to have them maintained and repaired as necessary.

Supplying and using a non-conforming instrument which has not completed the conformity assessment procedure is an offence. If an instrument is adjusted or repaired, it must be re-verified.

Seals are often used on measuring instruments for security purposes in the verification process.  Any interference with a seal or any other aspect of the mechanism of the instrument may invalidate its original verification.  Breaking a security seal automatically invalidates verification so that the instrument must be reverified.

Application of EU Standards

Only instruments meeting the requisite EU Standards in relation to non-automatic weighing instruments, may be placed on the market or put into service for use.  Placing on the market includes importation, offering for sale, distribution or supply by a manufacturer.  Breach constitutes an offence.

The Directive and regulations apply to

  • water meters;
  • taximeters;
  • gas meters;
  • active electrical energy meters;
  • certain liquid measuring meters;
  • automatic weighing machines;
  • material measures of length;
  • capacity serving measures;
  • exhaust gas analyzers; and
  • dimensional measurement instruments.

Measuring instruments must meet the detailed technical requirements set out in the Directive.  Manufacturers may use any technical solution that complies with the essential requirements provided for it.

EU Standards for Weighing and Measuring Instruments

EU Directive provides for free movement within the European Union of instruments weighing and measuring instruments, approved under the Act.  The Directive sets out the essential requirements for the relevant categories of instruments. The essential requirements can be met through the adoption by a manufacturer of a normative document containing technical specifications, recognized by the international metrology organization, in accordance with the procedure in the Directive.

Notified bodies may carry out various functions, such as type approval, verification, and quality assistance approval.  There are obligations on manufacturers in relation to the conditions on which they may issue a declaration of conformity and attach the CE marking and the supplementary metrology marks.

There are provisions for withdrawal from the market and the imposition of restrictions on instruments that bear the mark but do not meet the requirements of the regulation.

The Legal Metrology Services is the Irish authority under the Directive. It must assist the authorities in other states on request, in relation to market surveillance.  It must provide information to other EU states.

Conformity Assessment I

Certain prescribed types of instruments, are subject to conformity assessment requirement procedures on the manufacture and regularly thereafter. There are differing assessment procedures prescribed, for various types of equipment.  They include type verification and unit verification.

Certificates of conformity attest conformity. Instruments which have been assessed for conformity, are subject to further inspection from time to time. Certificates may be revoked where they cease to conform.

Instruments which are subject to conformity assessment and inspection procedures must bear a verification mark in the form prescribed.  It is an offence to possess such an instrument or to use it for a prescribed purpose, where it fails to comply with the conformity conditions.

Calibration devices and instruments are to be secured so as to enable any adjustment in them to be detected, insofar as possible.  Facilities for the security feature must be provided by the manufacturer, supplier or user.  The Legal Metrology Service may prescribe requirements for sealing and securing instruments.

Conformity Assessment II

The conformity assessment of a measuring instrument is carried out by the manufacturer by the application of one of a number of conformity assessment procedures.  There are separate procedures for each instrument. Where the conformity assessment procedure requires that the manufacturer provides technical documentation for specifications, that documentation is to contain prescribed information.

Instruments are presumed to comply with the essential requirements if they comply with the elements of the relevant national standards for the essential requirement concerned. It is presumed that measuring instruments comply with the appropriate tests if the corresponding test program has been performed which conforms with the essential requirements.

Application of CE Mark to Measuring Instruments

National legislation must not prohibit or restrict the marketing or use of measuring instruments that properly bear the requisite CE markings from other EU states.  Non-conforming measurement instruments may be seized by the national metrology office.

The application of the CE marking and supplementary metrology marking is to indicate conformity with the prescribed requirements. The marking is to be affixed under the control or responsibility of the manufacturer.  Where an instrument is too small to carry the markings, they may be put on the packaging.

The Minister may designate bodies for the purpose of performing tasks relating to conformity assessment. Each EU state is to notify other states of the nominated bodies.  The relevant legal metrology services are to notify each other of their certificates and quality approval systems issued or withdrawn, evaluation reports and certain other documents in connection with the performance of obligations under the Directive.

Verification Markings

The forms of CE marking are designated by law.  The design of the verification mark, non-conformity mark, obliteration mark and security seal are provided. Instruments intended to be used for the purpose of a trade, must not be used for the trade unless they have undergone the verification procedure and are stamped with the verification mark.

An inspector or authorised person may apply the verification mark to an instrument, where he has ascertained that it is in compliance with a valid and subsisting type-approval certificate, the tolerance for errors and other provisions applicable to verification.

An instrument intended to be used for a trade which is exempt from type approval is not to be used for the trade unless it has undergone a verification procedure and has been stamped with the verification mark.

An instrument intended for use for a trade which is of a type listed in the certificate or type approval granted or deemed to be granted, may not be used for the trade unless it has undergone a verification procedure and has been stamped with the verification mark.

A Verification mark may be refused if the inspector or authorised person believes the instrument is not sufficiently strong to withstand wear and tear for its normal use, is not suitable for use, is not clean or is not presented in a manner to facilitate testing.

Inspection of Instruments Used in Trade

Unless otherwise provided, instruments used in a trade must be inspected at least every two years.  The inspection period may be extended or reduced by the Metrology Service.  Surprise inspections may take place from time to time.

Inspectors may inspect instruments with EU and other verification marks.  They may prohibit continued use of instruments for the purpose of trade, where

  • the relevant tolerances / permissible errors are exceeded;
  • the instrument is no longer compliant with the applicable performance requirements;
  • the instrument has been repaired, altered or adjusted since verification;
  • the instrument has been broken or damaged;
  • the instrument is being used for a purpose for which it is not intended;
  • the instrument is not presented in a manner to facilitate testing;
  • the instrument bears an unprescribed mark;
  • the instrument fails to comply with the provisions of the regulations.

Where an inspector determines that an instrument exceeds the prescribed maximum permissible error, but by no more than 10 percent, or that the degree of noncompliance is not such that it should be immediately taken out of service, he may issue a notice giving reasons for the decision and require rectification within 20 working days.  If the rectification is undertaken, the nonconformity mark will not be applied.

Prohibition of Use of Instruments

An instrument may not be used for the purpose of a trade, where there is a nonconformity mark, where the verification mark has been obliterated or deemed invalidated or where the instrument has not undergone the verification procedure and been marked with the verification mark.  An instrument which must be verified and stamped must be re-stamped if it is dismantled and reinstalled.

An instrument may not be used for the purpose of a trade, other than in environmental conditions and in a manner which is intended in accordance with information supplied by the manufacturer or a supplier. An instrument must not be used in circumstances in which it may be prevented from operating consistently or accurately or which are likely prematurely to degrade its metrological characteristics.

Verification Procedures

Fees may be charged for verification and testing if goods in use in a trade. Persons wishing to have their measuring and weighing equipment verified, may pass it to an officer of the authority and pay the requisite fees.  The methods to be used for testing and the criteria are prescribed in detail in regulation.

The authority must test the equipment by reference to local or working standards or using testing equipment, as is considered appropriate. If the equipment falls within the prescribed limits of error, it is deemed to confirm.  Generally, a stamp must be applied and a record must be kept.

Enforcement of Legislation re Measuring Equipment

EU States must appoint persons for the purpose of undertaking market surveillance and ensuring compliance.  Authorised officers have substantial powers, similar to those granted to other investigatory and enforcement authorities, for the purpose of undertaking market surveillance.

Where the authority suspects that measuring instruments do not conform with the essential requirement, it notifies the manufacturers and its invites representations and submissions.  The authority, having been given the opportunity for making representations, provides a report to the Minister, a copy of which is also furnished to the manufacturer.

Any person selling, importing or distributing measuring instruments or having them in his possession, must ensure that the required conformity assessment procedure has been applied.  Failure to do so is an offence.  Where compliance with the requirements for stamping or approval of instruments is impractical, the service may dispense with them, subject to such conditions as may be applied.

Powers of Inspectors

Inspectors appointed by the Legal Metrology Office have power at all times to enter premises, vessels, and vehicles where they believe instruments of the relevant type, are in use or where they are manufactured, supplied, imported or distributed.  They may inspect and examine instruments or goods for the purpose of establishing conformity with legislation. Non-conforming instruments may be marked as non-conforming.

Inspectors may require owners and employees to provide all reasonable assistance.  The production of books and records may be required. Instruments may be taken away and examined off the premises.   A receipt shall be given for goods removed. In certain circumstances, the owner of the premises may require the Office to buy the goods concerned.

Vehicles may be required to be brought to an appropriate centre for inspection and testing. Inspectors may seize and detain instruments, stamps, and goods which contravene the legislation.

It is an offence to obstruct or impede an inspector in carrying out a function or to fail to comply with a requirement to give reasonable assistance as required.  It is an offence knowingly to mislead an inspector in carrying out his functions.

Where a person is aggrieved by a seizure of goods under the powers conferred by the legislation, he may appeal to the District Court.  If the District Judge is satisfied that the procedure was carried out lawfully, he will confirm the seizure and retention.  Otherwise, he shall order the return of the goods and payment of compensation and expenses, if any, as is considered reasonable.

Orders re Conformity and Termination of Infringement

If the authority is of the opinion that the marking and metrology marks have not been properly affixed, it may give a direction in writing to the manufacturer requiring conformity and termination of the infringement. Where a person persists in failing to comply with a direction, the authority may report to the Minister, setting out its opinion and a recommendation as to action. The person aggrieved by the direction may appeal to the Minister.

Where the Minister having considered the authority’s report, considers it appropriate and agrees with the opinion of the authority, it may prohibit the placing of the instruments in the market.  He may impose restrictions or require the relevant entity or persons to take steps to withdraw the goods in the market.  They must comply with the direction. The direction may state whether noncompliance is systematic or incidental.

Where noncompliance is systematic, the EU Commission is immediately informed. Where a direction is not complied with, the Minister may apply summarily to the High Court for orders to give effect to the direction.

When the Minister proposes to revoke a designation or issue a direction by way of enforcement, he must give notice of the proposal to the person concerned.  There is an appeal mechanism set out in the legislation.  The Minister appoints an officer to hold an enquiry in relation to the appeal.  An assessor may be appointed in order to assist him in making a report. The assessor is to be independent.  There is provision for an appeal to the High Court by persons aggrieved by decisions by way of enforcement.

Offences I

The legislation creates various offences. Several of the more significant offences are mentioned above.

A person who has in his possession, any trade or weighing equipment which is false and unjust is guilty of an offence.

It is an offence to

  • tamper with any plug or seal for reception of a stamp;
  • to deface or alter a stamp;
  • to remove a stamp
  • to alter any equipment after it has been stamped to make it false and unjust or
  • to sever or tamper with any wires or means by which a stamp is attached.

Offences II

Forgery or counterfeiting of a mark, the application of a mark or the use of an instrument with a forged or counterfeit mark, is an offence.  It is an offence, knowingly to render an instrument inaccurate or to use, supply or dispose of an instrument rendered inaccurate. It an offence knowingly, to mark any plug or plate intended for use for the reception of a mark, to remove any mark or plate from an instrument, or to insert such mark, plug or plate into another instrument other than that for which it is lawfully inscribed.

It is an offence, falsely to represent that an instrument is in accordance with a type approved in a conformity assessment or that an instrument in use is type approved. It is an offence to remove, obliterate or deface any marking or tag or wilfully break any seal attached to a prescribed instrument, if the marking, tag or seal has been placed by an inspector or by authorised body.

It is a defence if the person removes the marking or tag, or breaks the seal for the purpose of altering, adjusting or repairing an instrument provided the user is informed.  The user must as soon as practicable, re-verify the instrument.

Offences III

Where an offence is committed by a corporate body under the legislation and it is shown to be committed with the consent, or attributable to neglect on the part of any director, manager, secretary or similar officer or person purporting to act in such capacity, that person is also deemed guilty of an offence.

An offence committed by an employee or agent of the accused is attributable to the employer or principal unless the accused established that it was committed without his or her knowledge, and he exercised all due diligence to prevent its commission.

A person convicted of an offence under the legislation on indictment may be subject to a fine up to €12,700 or at the discretion of the Court, two years’ imprisonment or both. A person found guilty of an offence prosecuted summarily, is subject on conviction to a fine up to £1,500 and 12 months’ imprisonment and to forfeiture of the goods and instruments.

If the contravention continues, a person is liable for a further offence, subject to a fine of up to €127 per day. Offences triable summarily under the legislation, may be prosecuted within 12 months.  They may be prosecuted by the Director of the Legal Metrology Service.

References and Sources

Irish Texts

Consumer Law Rights & Regulation    Donnelly & White (2014)

Consumer Protection Act 2007 Annotated  Bird (2008)

Consumer Rights Long (2004)

Commercial & Consumer Law: Annotated Statutes O’Reilly, P (2000)

UK Texts

Consumer Sales Law: The Law Relating to Consumer Sales and Financing of Goods 3rd ed

John MacLeod, James Devenney (2019)

Electronic Consumer Contracts in the Conflict of Laws 2nd ed Zeng Sophia Tang (2018)

The Law of Consumer Redress in an Evolving Digital Market: Upgrading from Alternative to Online Dispute Resolution Pablo Cortes (2017)

Blackstone’s Statutes on Commercial & Consumer Law 2017-2018 Francis Rose

Consumer and Trading Standards: Law and Practice 2017 Bryan Lewin, Jonathan Kirk

Woodroffe and Lowe’s Consumer Law and Practice Woodroffe and Lowe’s Consumer Law and Practice 10th ed Geoffrey Woodroffe, Chris Willett, Christian Twigg-Flesner (2016)

Butterworths Trading and Consumer Law Looseleaf Annual Subscription Deborah L. Parry, Roland Rowell (2016)

Butterworths Commercial and Consumer Law Handbook 8th ed Richard B. Mawrey, Tobias Riley-Smith (2015

Consumer and Trading Standards: Law and Practice 4th ed

References and Sources

Metrology Act 1996

 Weights and Measures (General) Regulations 1928 [Vol. XXII p.

249] S.R.& O. No. 71 of 1928

 Weights and Measures (Departmental Fees) Order 1928 [Vol.

XXII p. 333] S.R.& O. No. 78 of 1928

 Gas Meters (Stamps) Regulations 1958, S.I. No. 138 of 1958457

 Weights and Measures (Taximeter : Section 136 of the Road

Traffic Act, 1933) (Amendment) Regulations 1958, S.I. No. 139

of 19584

 Weights and Measures (Metric Equivalents) Order 1976, S.I. No.

91 of 1976

 Metrology Act, 1996 (Commencement and Establishment Day)

Order 1997, S.I. No. 177 of 1997

 Legal Metrology (Type Approval) Regulations 2006, S.I. No. 207

of 2006

 Legal Metrology (European Conformity Assessment of

Measuring Instruments) Regulations 2007, S.I. No. 160 of 2007


 Legal Metrology (General) Regulations 2008, S.I. No. 323 of 2008

 Legal Metrology (European Conformity Assessment of Measuring Instruments) (Amendment) Regulations 2010, S.I. No. 543 of 2010