KR Approves Ammonia-Fueled Ship Safety Solution ‘Hi-CLEARS’ from HD Hyundai

[By: Korean Register]

KR (Korean Register) has granted Approval in Principle (AIP) for the ammonia-fueled ship safety solution ‘Hi-CLEARS’ (Hyundai integrated Clean Liquid based Ammonia Release mitigation system with SCR).  The system was developed in collaboration with HD Hyundai Heavy Industries (HD HHI) and HD Korea Shipbuilding & Offshore Engineering (HD KSOE) and was announced on September 11 at Gastech 2025 in Milan, Italy. 

The approval is the result of a joint development project aimed at overcoming safety and regulatory barriers to the commercialization of ammonia-fueled vessels and at laying the groundwork for future international technical standards. The newly developed Hi-CLEARS is a safety-enhancing system that swiftly captures any ammonia gas leaked during operation, converts it into aqueous ammonia, and uses it as a reductant in an SCR (Selective Catalytic Reduction) system. This innovative solution not only eliminates potential ammonia leakage but also achieves a ‘Zero Discharge’ of ammonia to the atmosphere and sea, earning recognition as a breakthrough technology. 

KR took a central role in amending IACS Unified Requirement M77, which governs the application of SCR systems on ships. The revision, based on risk assessment, now permits aqueous ammonia and ammonia itself to be used as reductants, where previously their use was restricted. This change provides the technical foundation needed for the commercialization of Hi-CLEARS and demonstrates KR’s commitment to shaping international safety requirements. 

YOO Byungyong, Senior Vice President of HD KSOE, said: “Hi-CLEARS safely processes ammonia leaks and treats the resulting liquid through SCR, thereby meeting both safety and environmental regulations. Through close cooperation with KR, we have enhanced its commercial viability while also strengthening our global competitiveness.” 

RYU Hongryeul, Executive Vice President & CTO of HD HHI, added: “This joint development marks an important achievement in addressing two key challenges of ammonia-fueled vessels—reducing ammonia discharge and utilizing it for harmful gas treatment. Leveraging the strong partnership between shipyards and KR, we will further reinforce our leadership in advancing next-generation eco-friendly technologies.” 

LEE Yongsok, Executive Vice President of KR, stated: “This AIP goes beyond technical validation to advancing international standards. By contributing to revisions such as IACS Unified Requirement M77, KR is helping to create the regulatory foundations that make ammonia-fueled ships a safe and viable reality. We remain committed to refining technical rules and requirements in line with technological progress and evolving industry needs, and to leading the decarbonization transition as a trusted partner to the global maritime community.”