ASTM D8221-23 PDF
Name in English:
St ASTM D8221-23
Name in Russian:
Ст ASTM D8221-23
Original standard ASTM D8221-23 in PDF full version. Additional info + preview on request
Full title and description
Standard Practice for Determining the Calculated Methane Number (MNC) of Gaseous Fuels Used in Internal Combustion Engines. This practice specifies the calculation method, required input data and adjunct computational tools (Excel/DLL) used to produce the calculated methane number (MNc) for gaseous fuels such as natural gas, CNG, LNG, LPG and renewable gases used in engine applications.
Abstract
ASTM D8221-23 defines a reproducible procedure to calculate the methane number (MNc) of gaseous fuels from measured composition and properties. The standard provides algorithmic tools (adjunct Excel files and dynamic link libraries) to perform conversions, normalization and the MNc calculation, and includes guidance on uncertainty and reporting of results. It replaces the previous 2018/2018a edition and is the 2023 revision of the D8221 practice.
General information
- Status: Published / Active standard.
- Publication date: May 1, 2023 (D8221-23).
- Publisher: ASTM International.
- ICS / categories: 75.160.30 (Gaseous fuels).
- Edition / version: D8221-23 (2023 revision; replaces D8221-18ae1).
- Number of pages: 10 pages (standard text).
Scope
This practice provides a method to determine the calculated methane number (MNc) for gaseous fuels used in internal combustion engines from a gas composition analysis. It covers required input composition formats (mol%/mass%), normalization and conversion rules, the computation algorithm provided via adjunct files (Excel and DLL), and guidance on uncertainty and reporting. The method is intended for use with fuels such as natural gas, CNG, LNG, LPG and RNG that are evaluated for engine knock sensitivity.
Key topics and requirements
- Definition and purpose of the calculated methane number (MNc) for assessing knock propensity of gaseous fuels.
- Required gas composition inputs and allowable formats (mol %, mass %) and the required normalization/conversion steps.
- Provision and use of adjunct computational tools (Excel files and dynamic link libraries) to perform the MNc calculation and conversions.
- Reference to related calculation annexes and normative documents (for example annex material tied to EN/ISO calculation guidance).
- Reporting requirements, recommended significant digits and discussion of measurement uncertainty associated with calculated MNc values.
Typical use and users
Used by gas analysis laboratories, fuel producers and suppliers, engine and vehicle manufacturers, certification and regulatory bodies, and researchers who assess fuel quality and compatibility with engine designs. The standard is applied when determining the relative knock resistance of gaseous fuels for engine commissioning, specification, compliance and research.
Related standards
References and related documents commonly associated with D8221-23 include EN 16726 (Gas infrastructure — Quality of gas) Annex A (calculation of methane number), ISO 14912 (gas analysis conversion), ASTM D4150 (terminology relating to gaseous fuels) and other gas-analysis/quality standards; the D8221 practice cites these documents and aligns calculation procedures accordingly.
Keywords
Calculated methane number, MNc, methane number, gaseous fuels, natural gas, CNG, LNG, LPG, RNG, gas composition, engine knock, fuel quality.
FAQ
Q: What is this standard?
A: ASTM D8221-23 is a standard practice that specifies how to calculate the methane number (MNc) of gaseous fuels from composition data and provides accompanying computational tools to perform the calculation.
Q: What does it cover?
A: It covers required input data formats, normalization and conversion methods, the MNc calculation algorithm (delivered as adjunct Excel/DLL files), and guidance on uncertainty and reporting of calculated methane numbers for engine applications.
Q: Who typically uses it?
A: Gas testing laboratories, fuel suppliers, engine manufacturers, regulatory and certification bodies, and researchers concerned with fuel quality and engine compatibility use this standard.
Q: Is it current or superseded?
A: D8221-23 is the current published edition (2023) and supersedes the earlier D8221-18ae1 edition. There is a recorded work item (WK97264) to revise D8221 to update references (for example to ISO 17507-1) and adjunct tooling; users should check committee activity if they require the very latest revision status.
Q: Is it part of a series?
A: D8221 is part of ASTM's D20 committee work on gaseous fuels and fuel analysis; it is associated with other gas-quality and analysis standards (for example D4150 and referenced international/European calculation documents).
Q: What are the key keywords?
A: Methane number, MNc, calculated methane number, gaseous fuels, natural gas, CNG, LNG, LPG, RNG, gas composition, engine knock.