ISO 6338-2:2024

Overview

ISO 6338-2:2024 specifies a standardized method to calculate greenhouse gas (GHG) emissions during natural gas production, gas processing and transport up to the inlet valve of an LNG liquefaction plant. Applicable to onshore and offshore systems (and adaptable to biogas or non-traditional gas), it covers all operational upstream facilities and emission sources - including flaring, combustion, cold vents, process vents, fugitive leaks and emissions from imported energy. Gases addressed are CO2, CH4, N2O and fluorinated gases. The standard defines preferred units, conversion rules, and recommends measurement instrumentation and estimation methods for monitoring and reporting emissions.

Key topics and requirements

• Inventory boundary and scope: covers production, processing and pipeline transport to the LNG plant; excludes exploration, construction, decommissioning and vegetation losses. Emissions are allocated across scope 1, scope 2 and scope 3 per ISO 6338-1.
• Quantification steps: develop an upstream flow diagram; identify GHG sources for each process step; and allocate emissions where multiple commercial products are produced.
• Emission sources: combustion, flaring, venting, fugitives, imported energy, and process emissions. Both measured and estimated emissions are addressed.
• Allocation rules: allocation principles for multi‑product facilities (e.g., associated gas with oil, LPG extraction) to assign correct GHG shares to gas destined for liquefaction.
• Complex networks: guidance for LNG plants fed from a gas grid, including use of operating averages (e.g., 12‑month averages) and tracing flows/compositions.
• Quality management and reporting: requirements for GHG inventory quality, reporting practices and independent review are included.
• Units and instrumentation: preferred units, necessary conversions, and recommended measurement/estimation methods.

Applications and who should use it

ISO 6338-2:2024 is intended for:

• Oil & gas producers and LNG plant operators building upstream GHG inventories and carbon footprints.
• Sustainability, HSE and regulatory compliance teams preparing auditable GHG reports.
• Consultants, verifiers and auditors performing independent review and assurance.
• Engineers and asset managers designing monitoring systems and emissions measurement programs.
• Commercial teams requiring consistent GHG data for supply‑chain transparency, reporting and low‑carbon product marketing.

Practical uses include consistency in carbon accounting across the LNG supply chain, informing reduction strategies (leak detection and repair, flaring minimization, energy efficiency), and supporting life cycle assessment and corporate climate disclosure.

Related standards

• ISO 6338-1:2024 - General principles and KPIs for the LNG chain
• ISO 14064-1 - GHG quantification and reporting at organization level
• ISO 14044 - Life cycle assessment requirements and guidelines

Keywords: ISO 6338-2:2024, GHG emissions, LNG chain, natural gas production, gas transport, fugitive emissions, flaring, methane, carbon footprint, emissions inventory.