Overview - ISO 14978:2018 (Geometrical product specifications for GPS measuring equipment)
ISO 14978:2018 establishes general concepts and requirements for GPS measuring equipment used in dimensional metrology. It defines the scope, terms, design characteristics and metrological characteristics (e.g., for micrometers, callipers, gauge blocks, rotary axis form measuring instruments) and provides guidance for the development of standards for specific GPS measuring equipment. The standard is intended to improve communication between manufacturer/supplier and customer/user and to make specification, selection and calibration of measuring equipment more accurate and consistent.
Key technical topics and requirements
- Terms and definitions: Harmonizes vocabulary with ISO/IEC Guide 99 (VIM) and related guides to avoid ambiguity in specifications.
- Design characteristics: Describes common physical and functional design attributes that should be considered when specifying measuring equipment.
- Metrological characteristics: Guidance on identification, definition and selection of characteristics such as resolution, error of indication, temperature-related behavior, measuring force and geometric contact features.
- Specification of measurement performance (MPE): Presentation of MPE functions including constant, proportional, and combined proportional-plus-maximum forms to describe instrument performance limits.
- Calibration and verification: Guidance on calibration methods, verification procedures and handling of measurement uncertainty (references ISO 14253‑5:2015 and GUM principles).
- Presentation and documentation: Requirements for datasheets, marking and presentation of characteristic curves and reference points for traceability and clear communication.
- Annexes and model guidance: Includes templates and advisory annexes (data sheet, common design characteristics, test uncertainty, relation to GPS matrix model) to help standards writers and manufacturers.
Practical applications and who uses ISO 14978:2018
- Manufacturers and suppliers: To define and communicate product specifications, datasheets and guaranteed metrological performance of measuring instruments.
- Calibration and testing laboratories: For developing verification procedures, estimating measurement uncertainty and performing acceptance testing.
- Quality managers & metrology engineers: To select appropriate measuring equipment, set internal procurement criteria, and ensure traceability to GPS requirements.
- Standards developers: As a base document when writing standards for specific types of GPS measuring equipment.
- Procurement and inspection teams: To clarify contract specifications and decision rules for conformity based on ISO 14253 series.
Related standards
- ISO 14253‑1 (decision rules for conformity)
- ISO 14253‑5:2015 (uncertainty in verification of indicating instruments)
- ISO/IEC Guide 98‑3 (GUM) and Guide 99 (VIM)
- ISO 14638 and ISO 8015 (GPS framework and fundamental rules)
Keywords: ISO 14978:2018, GPS measuring equipment, geometrical product specifications, calibration, measurement uncertainty, metrological characteristics, MPE, micrometers, callipers, gauge blocks.