Overview
EN ISO 15112:2018 (ISO 15112:2018) - Natural gas - Energy determination - specifies accepted methods to determine the thermal energy content of natural gas by measurement or calculation. The standard defines how to combine a separately measured gas quantity (by mass or volume) with a measured or calculated calorific value to produce energy quantities, and it gives general approaches for calculating uncertainty. It applies to gas‑measuring stations of all sizes (from domestic meters to large high‑pressure transmission) and describes systems currently in use; new techniques are allowed if their performance is proven equivalent or better.
Key points from the scope
- Energy determination by measurement or calculation.
- Quantity measured separately (mass or volume) and combined with calorific value.
- Methods for uncertainty estimation and quality assurance.
- Only currently used systems are described; gas‑measuring systems themselves are out of scope.
- Commercial/official trade use may require national approvals and legal compliance.
Key Topics and Technical Requirements
The standard organizes practical requirements and guidance across these technical topics:
- General principles, symbols and units for consistent energy reporting.
- Gas measurement: volume measurement, pressure and temperature effects, density and compression factor considerations.
- Calorific value measurement: direct calorimetry, inferential techniques, correlation methods, sampling and gas quality tracking.
- Volume conversion and volume‑to‑mass conversion procedures.
- Calibration, data storage and transmission requirements for reliable measurement chains.
- Energy determination methods: direct and indirect approaches, interfaces, and calculation formulas.
- Assignment methods for calorific values (fixed and variable assignment, averaging, and gas quality tracking).
- Uncertainty and accuracy: principles and general means to calculate measurement uncertainty and identify bias.
- Quality control and assurance: traceability, plausibility checks, substitute values and monitoring.
- Informative annexes with instruments, conversion examples and practical calculation examples.
Practical Applications and Users
This standard is practical for professionals involved in:
- Gas utilities and transmission operators implementing energy accounting and billing.
- Custody transfer and commercial metering where accurate energy determination is required.
- Metering and instrumentation engineers designing measurement systems and conversions.
- Regulators, auditors and lab teams performing compliance checks, uncertainty assessment and quality assurance.
- Energy traders and network modelers using representative calorific values for settlement and balancing.
Benefits include improved accuracy of billed energy, standardized approaches for calorific assignment and uncertainty estimation, and clearer requirements for data handling and calibration.
Related Standards and Context
- ISO 15112:2018 has been adopted as EN ISO 15112:2018 / EN ISO 15112:2018 and supersedes the 2014 edition.
- Prepared by ISO/TC 193 (“Natural gas”) and endorsed by CEN; users should check national legal and authorization requirements before applying for commercial trade.
Keywords: natural gas, energy determination, ISO 15112:2018, calorific value, volume measurement, gas metering, uncertainty, energy calculation, custody transfer.