A List of Downloadable Metrology Guidebooks and Handbooks

Metrology:

BIPM (Bureau international des poids et mesures)
The unique role of the BIPM enables it to achieve its mission by developing the technical and organizational infrastructure of the International System of Units (SI) as the basis for the world-wide traceability of measurement results. This is achieved both through technical activities in its laboratories and through international coordination. BIPM publishes, in addition to scientific articles by members of staff which appear in the open literature, the official reports of the CGPM and CIPM, the SI brochure entitled Le Système International d'Unités, and the journal Metrologia. Also published are a wide range of scientific Reports and Monographs, most written by members of the BIPM staff. Individual copies of BIPM publications may be obtained on request.
A List of Downloadable Guide Books from BIPM

EURACHEM
Eurachem is a network of organisations in Europe having the objective of establishing a system for the international traceability of chemical measurements and the promotion of good quality practices. It provides a forum for the discussion of common problems and for developing an informed and considered approach to both technical and policy issues. It provides a focus for analytical chemistry and quality related issues in Europe.
A List of Downloadable Guide Books from EURACHEM

EURAMET  (European Association of National Metrology Institutes)

Our mission is to develop and disseminate an integrated, cost effective and internationally competitive measurement infrastructure for Europe. Always taking into account the needs of industry, business and governments. With our services we support our members to meet their national requirements and to establish a balanced European measurement infrastructure. To enhance benefits of metrology to society is one of the highest priorities for EURAMET and its members. EURAMET has published multiple calibration guides intended to improve harmonisation in the calibration of measuring instruments.
A List of Downloadable Guide Books from EURAMET

International Laboratory Accreditation Cooperation (ILAC)
International Laboratory Accreditation Cooperation is the international organisation for accreditation bodies operating in accordance with ISO/IEC 17011 and involved in the accreditation of conformity assessment bodies including calibration laboratories (using ISO/IEC 17025), testing laboratories (using ISO/IEC 17025), medical testing laboratories (using ISO 15189) and inspection bodies (using ISO/IEC 17020).

Accreditation is the independent evaluation of conformity assessment bodies against recognised standards to carry out specific activities to ensure their impartiality and competence. Through the application of national and international standards, government, procurers and consumers can have confidence in the calibration and test results, inspection reports and certifications provided.
ILAC Publications and Resources

Measurement Library
The Measurement Library is a collection of over 69,000 bibliographic references and downloadable documents related to flow measurement. It is a collaboration between a variety of contributors whose primary purpose is serve as a repository for technical material that is easily accessible for industry users and researchers. 

The 2017 Flow Measurement Institute proceedings can now be downloaded. In addition, all North Sea Flow Measurement Workshop proceedings can now be downloaded thanks to an updated agreement with NEL and FMI. 
The Measurement Library
 
Measurement Standards Laboratory of New Zealand (MSL)
Technical Guides are published by the Measurement Standards Laboratory to provide assistance with measurement techniques.
MSL Technical Guides Available for Download

The National Institute of Standards and Technology (NIST)
The National Institute of Standards and Technology was founded in 1901 and now part of the U.S. Department of Commerce. NIST is one of the nation's oldest physical science laboratories. Congress established the agency to remove a major challenge to U.S. industrial competitiveness at the time—a second-rate measurement infrastructure that lagged behind the capabilities of the United Kingdom, Germany, and other economic rivals.
A List of Downloadable NIST Handbooks

The National Physical Laboratory (NPL)
The National Physical Laboratory  is a world-leading centre of excellence in developing and applying the most accurate standards, science and technology available. NPL guides aim to improve measurement understanding and technical abilities across the UK and the rest of the world.
A List of Downloadable Guide Books from NPL

Legal Metrology:

The Asia-Pacific Legal Metrology (APLMF)
The Asia-Pacific Legal Metrology Forum APLMF is a grouping of legal metrology authorities, whose objective is the development of legal metrology and the promotion of free and open trade in the region through the harmonisation and removal of technical or administrative barriers to trade in the field of legal metrology. As one of the regional organisations working in close liaison with the OIML, the APLMF promotes communication and interaction among the legal metrology organisations and seeks harmonisation of legal metrology in the Asia Pacific region.
A List of Downloadable Guide Books from APLMF

OIML - International Organisation of Legal Metrology
The OIML issues several categories of publications:
International Recommendations, which are intended as model regulations for a number of categories of measuring instruments, and which OIML Member States are morally obliged to implement as far as possible;
International Documents, which are informative and are intended for guidance purposes; and
other publications such as Vocabularies, Guides, Basic Publications and Expert Reports.
WELMEC - European Cooperation in Legal Metrology (originally Western European Legal Metrology Cooperation)
The principal aim of WELMEC is to establish a harmonised and consistent approach to European legal metrology. Currently 38 countries are represented in the WELMEC Committee.
A List of Downloadable Guide Books from WELMEC