ISO 6338:2023

Overview - ISO 6338:2023 for GHG emissions at LNG plants

ISO 6338:2023 specifies a standardized, auditable method to calculate greenhouse gas (GHG) emissions from liquefied natural gas (LNG) liquefaction plants (onshore or offshore). The inventory boundary runs from the plant inlet flange through LNG storage and loading up to the offloading arms for truck, ship or railcar. The standard addresses operational emissions (including start‑ups, maintenance and turnarounds) and excludes construction, commissioning, extension and decommissioning phases. It covers all GHG sources relevant to LNG production and allocation to co‑products, enabling consistent carbon footprinting for the LNG industry.

Key technical topics and requirements

• GHG inventory boundaries: Defines facility, organizational and reporting boundaries and clarifies which upstream/downstream activities are covered in general terms.
• Scope 1, 2 and 3: Scope definitions and inclusion of direct and indirect emissions relevant to the responsible organization.
• Identification of emission sources: Comprehensive coverage of combustion, flaring, venting (including Boil‑Off‑Gas), cold/process vents, fugitive leaks, imported energy and utilities.
• Quantification approaches: Recommendations for measurement, estimation methods and preferred units of measurement; guidance on frequency and relevant reporting periods.
• Allocation: Methodology to allocate GHG emissions when multiple hydrocarbon products (LNG, LPG, condensate, domestic gas, sulphur, power export) are produced.
• Carbon capture: Guidance on opportunities and how to quantify capture benefits.
• Quality management: Requirements for QA/QC, uncertainty estimation, documentation, archiving and independent review to support an auditable GHG inventory.
• Supporting materials: Informative annexes include conversion factors, international climate initiatives and example allocation calculations.
• Normative references: Aligns with ISO 14064‑1, ISO 14044 and industry methodologies (e.g., API guidance).

Practical applications - who uses ISO 6338:2023

• LNG plant operators and facility engineers seeking a standardized method to measure and report GHG emissions.
• Environmental and sustainability managers preparing auditable carbon footprints and regulatory reports.
• Internal and external auditors, verification bodies and regulators assessing GHG inventories.
• Commercial teams, buyers and investors requiring comparable emissions data for procurement, offsets, carbon trading or low‑carbon product labeling.
• Project teams evaluating carbon reduction options (e.g., energy efficiency, electrification, carbon capture).

Related standards and benefits

• Related to ISO 14064‑1 (organization‑level GHG quantification) and ISO 14044 (life cycle assessment) - helps integrate LNG plant‑level emissions into broader reporting frameworks.
• Benefits include consistency, transparency and traceability of LNG GHG data, improved comparability across facilities, and a practical basis for emissions reduction strategies and market mechanisms (offsets/trading).