Overview
ISO/TS 18683:2021 - Guidelines for safety and risk assessment of LNG fuel bunkering operations provides a risk‑based framework for planning, assessing and managing the transfer of liquefied natural gas (LNG) as a ship fuel. The technical specification focuses on the LNG bunker transfer interface - including shore, floating/mobile and ship‑to‑ship supply scenarios - and sets out minimum functional requirements qualified by structured risk assessment. This second edition (2021) updates bunkering scenarios, adds design‑stage and operational risk assessment concepts, and introduces Quantitative Consequence Assessment and stakeholder roles.
Key topics and technical requirements
- Scope of bunkering scenarios: shore‑to‑ship, mobile‑to‑ship, ship‑to‑ship; applicable to seagoing and inland vessels.
- LNG properties and hazards: behaviour, potential hazardous situations (vapour, mist, cryogenic effects, RPT/BLEVE risks).
- Risk assessment framework:
- Hazard identification (HAZID), risk analysis and risk evaluation.
- Design stage and operational risk assessments.
- Quantitative Consequence Assessment and individual risk considerations.
- ALARP (as low as reasonably practicable) principle and mitigation hierarchy.
- Operational controls:
- Safety zones, monitoring and security areas, and methods to determine them (Annex B).
- Simultaneous operations (SIMOPs) management and coordination.
- Emergency shut‑down (ESD) and incident reporting requirements.
- Functional requirements: minimum functional expectations for the LNG bunker transfer system (detailed design requirements are referenced to ISO 20519 to avoid duplication).
- Roles & responsibilities: clear allocation among stakeholders - supply facility operators, receivers, port authorities and others.
- Training and documentation: competency expectations for personnel conducting bunkering operations.
- Annex A: individual risk acceptance criteria; Annex B: safety zone calculation methods.
Practical applications and users
ISO/TS 18683:2021 is intended for professionals who plan, design, operate or regulate LNG bunkering:
- Port and terminal operators planning bunkering sites and monitoring/security areas
- Offshore and marine fuel suppliers and bunker vessel operators
- Shipowners, operators and crew of LNG fuelled vessels
- Safety, risk and environmental engineers performing HAZID, consequence analysis and ALARP assessments
- Regulators and competent authorities developing local bunkering requirements or approvals
Using ISO/TS 18683 helps ensure transfers are conducted with consistent safety outcomes, documented risk justification, and clear operational limits for safe LNG bunkering.
Related standards
- ISO 20519 - specification for bunkering of LNG fuelled vessels (design details)
- IMO IGF Code and IGC Code
- ISO/IEC Guide 73, ISO 31010 (risk management guidance)
- STCW, NFPA and industry guidance (e.g., SGMF)