Area: 9 363 350 km2
Population: 260 605 050


In the United States, both national (Federal) and State laws on weights and measures apply. The Federal commercial weights and measures laws concern particular products (for example, only meat and poultry) or groups of products (for example, only consumer packaged goods) and supersede State laws. State laws and regulations govern the vast bulk of commercial trade measurements.

The Federal laws on commercial trade, public and worker health and safety, and protection of the environment are contained in the U.S. Code and the regulations are contained in the U.S. Code of Federal Regulations. State laws and regulations are independent of each other. Often, local ordinances and regulations add additional complexity to trade measurement regulations.

At the State level, each State enacts its own laws and regulations that cover all commercial weights and measures including those matters covered by Federal law. This permits the States to enforce legal requirements on all weights and measures matters,

This decentralized structure and application of commercial weights and measures led to the establishment of the National Conference on weights and Measures (NCWM) in 1905 by the National Bureau of Standards; the NCWM is still sponsored by the National Institute of Standards and Technology (NIST), formerly the National Bureau of Standards. The Conference produces model laws and regulations and encourages their adoption by State and local agencies. All 50 States have adopted the NIST Handbook 44 "Specifications, Tolerances, and Other Technical Requirements for weighing and Measuring Devices " as has several agencies of the U.S. Department of Agriculture. These models are compatible with all Federal laws and thus a high degree of uniformity prevails.

1.1 Legal requirements for traceability

State laws require State primary standards to maintain traceability to the national standards in the possession of the National Institute of Standards and Technology.


The United States is signatory to the Treaty of the Meter (1875). The international meter and kilogram are the fundamental standards of the nation. The U.S. customary (inch-pound) system of weights and measures is defined in terms of the meter and kilogram.

The use of the customary system is provided for in Federal and State law; the use of the metric system is authorised by Federal and State law;

Information on units, systems, and tables of weights and measures is included in NIST Handbook 44 Specifications, Tolerances and Other Technical Requirements for Commercial weighing and Measuring Devices; To assist conversion to SI units, the Federal government now specifies its purchases in SI units, and the Federal Fair packaging and Labelling Act was revised to require metric (SI) units on consumer packages.


3.1 National organisation for legal metrology

On the Federal level, the main authority in matters of commercial weights and measures is:
Weights and Measures program (also known as the Office of weights and Measures OWM)
A357 Physics Building
National Institute of standards and Technology
Gaithersburg, MD 20899-0001
Telephone: 1-301-975-4004
Fax: 1-301-926-0647
NIST OWM is responsible for the distribution and calibration of the physical reference standards used by each State (State standards). Also, NIST OW M provides the secretariat for the National Conference on weights and Measures (NCWM), and therefore provides the technical and administrative assistance to the National Conference in the drafting of model laws and regulations. NIST publishes annual editions of NIST Handbooks 44 and 130 and periodically publishes other handbooks on laboratory and field procedures.

A separate office within NIST has responsibility for all OIML activities and manages U.S. representation and participation under the terms of the Convention of the Treaty. The manager of the program is the U.S. member of the International Committee of Legal Metrology (C1ML). Information on the NIST program may be obtained from:
The Standards Management Program
Office of Standards Services
National Institute of Standards and Technology
Gaithersburg, MD 20899-0001
Telephone: 1-301-975-4023
Fax: 1-301-963-2871
In the U.S.A., the responsible authorities for non-traditional metrology services such as occupational health and safety, medical applications and pollution measurement and control exist in various Federal and State departments and agencies. Information on specific U.S. national regulations (standards) in these areas may be obtained from:
National Center for Standards and Certification Information (NCSCI)
TRF Building, Room A 163
National Institute of Standards and Technology
Gaithersburg, MD 20899-0001
Telephone: 1-301-975-4040
Fax: 1-301-926-1559

3.2 Custodian of National Standards

For All Physical Quantities:
Office of Measurement Services, Calibrations program
National Institute of Standards and Technology
Gaithersburg, MD 20899-0001
Main Publications:

The following publications by NIST have contents of particular interest to metrologists:

3.3 National organisation responsible for maintaining primary standards

The United States Primary Standards are held and maintained by the National Institute of Standards and Technology!

3.4 Regional and local verification organisations

Each State has one or more regulatory bodies in the field of weights and measures. In many States, these bodies are in the departments of agriculture.
Some States have local enforcement bodies at the county and city levels. A directory of these bodies is available from the NIST OWM (see clause 3.I). The OWM accredits State weights and Measures Laboratories in mass, volume, length, and temperature.

3.5 Instrument calibration and evaluation systems

Together with the NCWM, the NIST OWM sponsors the National Type Evaluation Program (NTEP) for evaluating commercial measuring devices. Application forms, criteria, and test procedures for type evaluation are available from:
NTEP Administrator
A357 Physics Building
National Institute of Standards and Technology
Gaithersburg, MD 20899-0001
Telephone! 1-301-975-4013
Fax: 1-301-926-0647
Measuring devices which are not commercial trade devices can be calibrated by NIST, by laboratories traceable to NIST, or by service companies using other standards calibrated by NIST or by secondary laboratories.

In addition NIST has a program for producing and Marketing?Standard?Reference?Materials.?
Information on calibrations and standard reference materials may be obtained from:
Office of Measurement Services
Technology Services
National Institute of Standards and Technology
Physics Building, Room B 354
Gaithersburg, MD 20899-0001
Telephone: 1-301-975-4861
Fax: 1-303-948-3825
A great number of metrology laboratories (about 500) are members of an Association called the National Conference of Standards Laboratories (NCSU. Its aims are to solve problems common to calibration laboratories, in particular, by organising symposia and training courses. NIST is a member of NCSL. Information about these activities may be obtained from:
National Conference of Standards Laboratories
Suite 305 B
1800 30th Street
Boulder, Colorado 80301
Telephone: 1-303-440-3339


In general, all instruments or measuring systems for weighing or measuring in commercial transactions are subject to legal control. Legal control over devices is largely exercised by the States. The types of devices are those covered in NIST Handbook 44.

Other instruments, such as gas and electrical energy meters, instruments used in health care and protection, etc., may also be subjected to regulation by governmental agencies other than the weights and measures service.


5.1 Legal and technical requirements for type approval

The National Type Evaluation program is operated by NIST in co-operation with the National Conference on weights and Measures, the States, and the private sector for determining, on a uniform basis, the conformance of a "type" of device or system with the relevant provisions of NIST Handbook 44. Evaluations are conducted on a fully cost-reimbursable basis. If the device or system meets all of the requirements, NIST issues a Certificate of Conformance, copies of which are sent to the manufacturer and to each State; States, in turn, accept these certificates as evidence of compliance with State laws and regulations requiring type approval.

5.2 Authority responsible for issuing type approval

Under the National Type Evaluation program, NIST is the authority responsible for issuing type approval certificates.

5.3 Recognition/acceptance of OIML Certificates

This subject is under development at the current time. NTEP has been named the responsible authority for conducting OIML Certificate evaluations for the United States for R76 for non-automatic weighing devices and R60 for load cells.

5.4 Authority responsible for testing for type approval

The type evaluation testing process is conducted by NIST, in other NTEP authorised Federal and State laboratories, and for certain devices, by the Legal Metrology Branch, Industry Canada.

5.5 List of major test facilities available

NTEP authorised U.S. test facilities are located at NIST, the U.S. Department of Agriculture's Federal Grain Inspection Service, and the States of California, Maryland, New York, and Ohio.

5.6 Fee structure

Type evaluations are conducted on a cost-reimbursable basis; therefore, the fees vary according to the time spent on the evaluation and the costs associated with the particular testing laboratory. Additionally, an annual maintenance fee of $100.00 per certificate is until the device is no longer manufactured.


6.1 Legal and technical requirements for verification and reverification

The type evaluation is the first step of the regulatory process, Further steps include initial and subsequent verification by the States or local weights and measures agencies of the production devices or systems manufactured in conformance with the "type" described in a Certificate of Conformance and installed in a commercial application,

6.2 Range of equipment verified and reverified and any statistical information available

In general, all instruments or measuring systems for weighing or measuring in commercial transactions are subject to initial verification and periodic reverification by the States.
Some statistical information is currently gathered by the States. A national data gathering system is under development.

6.3 Fee structure

Fees are charged in some States to recover the costs or a portion of the cost of the verification system In some cases these fees are in the form of licensing or registration programs. In other cases direct "fee for service" programs exist.


7.1 Accreditation systems for legal metrology, calibration and testing laboratories. Traceability to national, regional, international or foreign measurement standards

Within the U.S.A., many sectors of the economy look to laboratory accreditation and related efforts to provide some assurance of the technical proficiency and competence of an entity to assess a product's or service's conformance to a set of prescribed standards. Requirements and assessment criteria vary by program and according to the product, system, or service being assessed. Federal, State, local and city governments have various laboratory accreditation programs as well as private-sector professionals and trade organizations.

One such Federal program, the National Voluntary Laboratory Accreditation program (NVLAP) at NIST, is applicable to calibration and testing laboratories seeking accreditation based on compatibility with international standards. The program activities are operated in conformance with ISO/IEC Guides 58 and 25. Accreditation is available to commercial labs, manufacturer's in-house labs, university labs, and Federal, State and local government facilities. Information on the NVLAP may be obtained from:
National Voluntary Laboratory Accreditation Program
TRF Building, Room A 162
National Institute of Standards and Technology
Gaithersburg, MD 20899-0001
Telephone: 1-301-975-4042
Fax: 1-301-926-2884
Ordering information on the following NIST publications on U.S. accreditation activities may be obtained from the NCSCI (see clause 3.5 for address):

7.2 Legal and applied metrological activities in product certification

In the United States, the Trade Agreements Act of 1979 implemented U.S. acceptance of the Standards Code of the General Agreement on Tariffs and Trade (GATT). Title IV of the Act specifies obligations for the Federal government, including responsibilities with regard to certification. Moreover, the Federal government is required to take reasonable measures to assure compliance with the requirements of the Act by State governments and the private sector.

There are many private sector organizations that engage in product certification activities.
The U.S. Department of Commerce maintains at NIST the National Center for Standards and Certification Information (NCSCI) which serves as a center for information on standards, specifications and related materials and serves as a resource for information on certification programs and activities. Information on this subject as well as on the following publications are available from NCSCI (see clause 3.1):

7.3 Legal and applied metrological activities in ISO 9000 quality management systems

The ISO 9000 Standard Series was implemented in the United States through development of ANSI/ASQC (American National Standards Institute/American Society for Quality Control) Q90 Series and later changed to the ANSI/ASQC Q 9000 Series when the '1994 editions of the series were adopted. ANSI is the U.S. member organisation in ISO and, through its National Committee, IEC. Interest in quality improvement has become the focus in many Federal, States and local governmental agencies and a key business strategy among companies. Hence, some Federal agencies, such as the U.S. Food and Drug Administration's Center for Medical Devices and Radiological Health is in the process of harmonising its Good Manufacturing Practices guidelines with a supplemented version of ISO 9001 and the Department of Defense has adopted the ANSI/ASQC Q90 Standard Series for use as appropriate. The interest these standards have generated throughout the public and private sector has resulted in an increase in the number of U.S.-based organizations offering quality system registration. In 1989 the Registrar Accreditation Board (RAB) was established as an affiliate of ASQC to develop a program to evaluate the quality of services offered by registrars. RAB was later incorporated within the American National Standards Institute (ANSI).

The NIST Standards Code and Information program has been designated to serve as the clearing house for the dissemination of Federal agency activities related to the ISO 9000 Series.

Information on Federal activities may be obtained from NCSCI (see clause 3.1).



Approximately 3 600 State and local weights and measures officials reporting to about 775 independent agencies enforce the Federal, States, and local regulations and laws governing commercial transactions. Another 7000 Federal officials enforce meat and poultry regulations under the U.S. Department of Agriculture Food Safety and Inspection Service. Federal agents at the Food and Drug Administration, U.S. Treasury's Customs Service, Bureau of Alcohol, Tobacco, and Firearms, the Federal Trade Commission, and the U.S. Department of Commerce's National Fisheries Service all provide some commercial trade enforcement and regulatory services. Approximately 70 000 private service and repair agents are licensed by the States to install and place repaired devices into service without government presence.

8.2 Qualification/Training

Qualifications and minimum training varies depending upon the government agency or private company that employs the inspector. Minimum requirements for some State and Federal jurisdictions are a bachelors degree with approximately 9-12 weeks formal training, 6 months on-the-job training, and final examinations in specific core capabilities leading to formal licenses. In other jurisdictions, minimum requirements may only be a high-school diploma with several months on-the-job partnership with more experienced personnel, requiring no formal course work or examination.

8.3 Training organizations and courses organised

The NIST weights and Measures program has managed for the NCWM the development of weights and measures short courses culminating in the publication of "modules" of trainer and student manuals for 3 to 5 day courses. NIST weights and Measures program also provides training in weights and measures laboratory metrology and specialised training such as liquid propane gas meter testing and packaged commodity training. State weights and measures agencies provide their own training to their staff, and contract for training from their sister agencies, local colleges, and management training providers. For example, the Institute of Weights and Measures is a small training organisation that provides short courses to State and local weights and measures agencies on an as-requested basis. The U.S. Department of Agriculture operates a meat and poultry inspector school in Denton, TX.

8.4 Range of functions

weights and Measures organizations in the U.S.A.:


9.1 Legislative control for packaging

The NCWM Uniform packaging and Labelling Regulation serves as the basis for individual State legislation and has been adopted in most States. It is updated annually and has been made fully compatible with the Federal Fair packaging and Labelling Act and all other Federal laws having to do with the subject. The text is included in NIST Handbook 130 Uniform Laws and Regulations. NIST Handbook 133 Checking the Net Content of packaged Goods has been adopted by Federal and State agencies.

9.2 Organisation responsible

Several Federal agencies as well as the various States are responsible for administering the packaging and labelling laws and regulations.


Sanctions vary from State to State as well as at the Federal level and may include administrative, criminal or civil penalties.

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