ISO 1998-6:2000

Overview

ISO 1998-6:2000 - Petroleum industry - Terminology - Part 6: Measurement - is an international, bilingual (English/French) terminology standard that defines terms used in the measurement of crude oils and petroleum products. It provides equivalent English and French terms with corresponding definitions to support consistent communication across the petroleum value chain, from the production field to the final user. The standard is one part of the ISO 1998 series on petroleum terminology and is intended for common industry usage (not a replacement for legally established metrology definitions such as VIM).

Key topics

ISO 1998-6 organizes measurement terms into numbered subcategories and serial term numbers (x.yy.zzz). Primary technical topics covered include:

• Static measurement (e.g., tank capacity, calibrated volume, calibration tables)
• Dynamic measurement (flow metering and related terms)
• Statistical analysis of measurement (precision and application of measurement data)
• Sampling (terms used when obtaining representative samples)
• Properties and instrumentation (measurement instruments and property descriptors)
• Calibration and standards (calibration practices and reference points)
• Acronyms (standardized abbreviations used in measurement contexts)

Example defined terms taken from the standard:

• calibrated volume - volume of a proving tank between the "empty" and "full" conditions as specified on its calibration certificate.
• calibration table / tank capacity table - table showing tank capacities or volumes corresponding to liquid levels measured from a reference point.
• critical zone - level range near the bottom of a floating roof tank where complex interactions occur; custody-transfer measurements should not be made within it.
• datum point - reference position used when preparing a calibration table.
• deadwood (positive / negative) - tank fittings whose volume either adds to or displaces liquid, affecting effective tank capacity.
• dip point - point on the dip-plate used during gauging to measure oil and water depths.

Applications and users

ISO 1998-6 is practical for:

• Measurement engineers and metrologists working on tank gauging, custody transfer and volume calculations
• Tank calibration technicians and laboratory staff preparing calibration tables
• Sampling officers and quality control teams in refineries, terminals and storage facilities
• Procurement, regulatory compliance and auditing professionals who need standardized terms
• Technical translators and documentation authors needing consistent bilingual terminology

The standard supports consistency in contracts, measurement reports, calibration certificates and training materials.

Related standards

ISO 1998-6 is part of the ISO 1998 series (Parts 1–7, 99). Bibliographic standards referenced include:

• ISO 4006 (fluid flow vocabulary)
• ISO 4259 (precision and test methods)
• OIML R 117 (measuring systems for liquids)
• VIM (International vocabulary of metrology) - some definitions adapted from VIM

Keywords: ISO 1998-6:2000, petroleum terminology, measurement, tank calibration, static measurement, custody transfer, tank gauging, sampling, metrology.