The introduction of MEGC solutions for H₂ logistics at higher pressures does not occur within a widely applicable, standardized operational framework. As an emerging market, the lack of harmonization in operating practices limits large-scale deployment and industrial maturity.
This protocol consolidates available information gathered from previous deliverables to define a structured baseline. Its objective is to enable operators and equipment providers to improve standardization efforts and facilitate the broader adoption of MEGC technologies — yielding safer, more economically viable, and more competitive alternatives within the industrialization of MEGC-based hydrogen logistics.
Consistent safety envelopes across operators and sites
Generic approaches applicable across diverse MEGC assets
Traceable alignment with applicable regulatory standards
Supports competitive and economically viable deployment
This protocol defines the operational conditions applicable to the filling of Type III and Type IV MEGC (Multi-Element Gas Containers) intended for the transport of compressed hydrogen. It covers all stages of the filling process — from MEGC reception on site to its release for transport.
Type III (metal liner with composite reinforcement) and Type IV (polymer liner with composite reinforcement) high-pressure vessels
Service pressures ranging from 200 bar to 700 bar, with initial filling pressures up to 20 bar (no empty start)
Ambient temperatures from −20°C to +45°C, with meteorological monitoring required at operating boundaries
Stationary hydrogen transfer units equipped with compression and/or cascade systems, with or without active cooling, staff
The protocol operates within hard physical limits defined by both station and MEGC parameters. Maximum deliverable pressure is bounded by the dispenser system (cascade or compressor maximum), and MEGC limits are set at 1.25 × NWP — corresponding to 437 bar at 350 bar NWP, 475 bar at 380 bar NWP, and 800 bar at 640 bar NWP.
All operations must be conducted within ATEX-compliant environments. Hydrogen concentration shall remain below 4% vol (LEL) in confined areas, with alarm thresholds at 25% LEL triggering preventive actions. Access is restricted to trained, authorized personnel only.
The protocol is not a static checklist — it is a constraint-driven, adaptive, and auditable framework. The following principles govern every design and operational decision.
All strategies operate strictly within predefined pressure, temperature, dP/dt, and SOC limits — including worst-case scenarios.
Each configuration results from a trade-off: filling time vs. energy consumption, throughput vs. equipment stress, simplicity vs. performance.
The protocol dynamically adapts to varying initial pressure, temperature, and ambient conditions — avoiding one-size-fits-all strategies.
Protocol definition considers the entire hydrogen transfer chain — station, storage, compression, and transport unit — ensuring global optimization.
Consistent outcomes are delivered despite sensor noise, environmental variability, and operational uncertainty.
Directly translatable into PLC/SCADA control logic, with clear decision rules and minimal operator ambiguity.
All decisions and outcomes are traceable, enabling compliance demonstration, incident analysis, and continuous improvement.
The approach is applicable across different MEGC assets and storage systems, supporting future standardization in hydrogen logistics.
Successful implementation of the hydrogen transfer protocol requires clear roles and responsibilities across all involved parties, from design to daily operations. Each stakeholder plays a critical part in ensuring safety and efficiency.
Provides technical specifications, maintenance guidelines, and supports design compliance for the containers.
Ensures MEGC maintenance, re-qualification, and overall asset integrity throughout its lifecycle and operation.
Manages MEGC transport, scheduling, and coordinates efficient supply chain movements to and from sites.
Directly manages the hydrogen transfer process, monitors parameters, and ensures safe, compliant filling operations.
Responsible for safe transport of MEGCs, pre-departure checks, and initial site coordination upon arrival.
Oversees and approves all protocol-related documentation, ensuring compliance with regulatory and operational standards.
The hydrogen transfer protocol is structured as a sequence of five consolidated operational phases — simplified from seven granular steps for field applicability. The CRIMP acronym (Check / Ready / Inject / Monitor / Purge & Close) provides an intuitive mnemonic for operators and automation engineers alike.
Phases 0 & 1: System pre-requisites, sensor/valve/ESD verification, visual inspection, grounding, and pressure compatibility checks.
Phase 2: Connection & inerting, certified leak-free connection, inerting if required, system readiness confirmed for pressurization.
Phase 3: Filling definition & execution, pressure ramp profile, controlled ΔP/dt within thermal and mechanical constraints.
Phase 4: Maintain below 100% SOC, stabilization, thermal equilibration, optional top-up, continuous P/T monitoring until final stabilized state is reached.
Phases 5 & 6: Valve closure, depressurization, disconnection, data logging, incident handling, and release authorization.
Color code: blue for documentary & compliance preparation, yellow for physical operator checks, and green for automated system checks.
Ensure that all equipment, interfaces, and safety systems are fully operational and compliant prior to any filling operation. This phase constitutes a mandatory hold point before proceeding to pre-filling checks — no filling operation may commence without successful completion.
The protocol is implemented as a finite state machine (FSM), ensuring deterministic and automatable execution across all phases. Every state transition is conditioned on validated hold points, and any fault at any state triggers an immediate transition to the safe fault state.
System initialized and pre-checks initiated
All pre-filling checks validated
Connection completed and certified
Leak test passed — filling authorized
Target pressure reached or stop condition triggered
Stabilization complete, all limits satisfied
Any state may transition directly to S7: Fault upon detection of an anomalous condition. Fault handling triggers:
Tank pressure — primary filling control variable
Gas temperature — thermal limit enforcement
Pressure ramp rate — dynamic safety threshold
Volumetric flow rate — filling performance metric
Safety-critical signals — hydrogen leak detection, flame detection, and ambient H₂ concentration — are handled within the SIS, operating with fail-safe logic (loss of signal = alarm/trip) and highest-priority interlocks that override all process control commands.
Continuous threshold monitoring (% LFL) → ESD activation, valve isolation, ventilation
Critical emergency → full system ESD, isolation, depressurization, fire safety activation
25% LEL alarm threshold → preventive actions; 100% LEL (4% vol) → immediate shutdown
Every phase transition is conditioned on a formal GO / NO-GO validation. Any rejection must be argued, registered in the filling record, and accompanied by the immediate action taken and a long-term corrective initiative to prevent recurrence.
An incident is defined as any deviation from normal operation, including pressure or temperature exceedances, leak detection, hydrogen concentration above threshold, equipment malfunction, or unexpected activation of safety systems. Every incident triggers a mandatory structured response.
Halt filling operation and secure installation via isolation and shutdown if required
Evacuate personnel if necessary and inform the responsible supervisor immediately
Root cause analysis, identification of corrective actions, and update of operational rules if necessary
The long-term value of this protocol extends beyond individual filling operations. Systematic data collection and analysis enables the hydrogen transfer ecosystem to evolve, self-correct, and continuously improve operational safety and efficiency.
Build a longitudinal record of MEGC and station behavior across all operations, enabling statistical trend analysis and behavioral benchmarking over asset lifetime.
Detect abnormal trends and recurring issues before they escalate — supporting predictive maintenance and early identification of systemic failure modes.
Use operational history to plan maintenance interventions proactively, reducing unplanned downtime and extending the operational lifetime of MEGC assets and station equipment.
Continuously refine filling procedures, safety thresholds, and control parameters based on real-world operational data — closing the loop between field performance and protocol
A structured operational framework for MEGC-based hydrogen logistics — covering system pre-requisites, filling execution, safety integration, and full traceability from reception to transport release.