IACS Updates Unified Requirement on Crankcase Explosions
As the industry shifts towards alternative fuels in response to environmental regulations and sustainability goals, the safety risks associated with these fuels cannot be overlooked, says the International Association of Classification Societies (IACS). Crankcase explosions, a critical hazard in engine operation, becomes even more concerning in the context of gas and low flashpoint fuels.
IACS has therefore published the latest edition of Unified Requirement (UR) M10, which introduces new safety requirements to protect internal combustion engines from crankcase explosions.
Revision 5 of UR M10 builds on key existing safety standards essential for protecting against crankcase explosions. These include the requirements for crankcases to be constructed to withstand the internal pressures generated by potential explosions. For engines with a crankcase volume exceeding 0.6 m³, additional explosion relief valves are required to safely manage the excess pressure.
Furthermore, a crankcase explosion relief valve must be in compliance with type testing procedures stipulated in IACS UR M66, as incorporated in IACS Members Rules, ensuring they meet the unified technical requirements fit for safety purposes, designed to safeguard against explosions.
This new edition of UR M10 was achieved through extensive collaboration with key industry stakeholders, including engine manufacturers.
In this latest edition, IACS has also introduced the following improvements to address the safety requirements specific to engines fueled by gas or low flashpoint fuels:
• Airflow Requirements: Technical conditions for the external airflow into the crankcase have been specified for engines fueled with gas or low flashpoint fuels, ensuring operational safety.
• Lower Explosive Limit (LEL): The revised UR M10 now defines the Lower Explosive Limit (LEL) for gas, fuel vapors, or mixtures in the crankcase, contributing to enhanced safety measures.
• Crankcase Pressure Control: To prevent interference with critical safety devices, such as oil mist detection systems during forced extraction of the crankcase atmosphere.
• Safety Evaluation: Engines fueled by gas or low flashpoint fuels must undergo a comprehensive safety evaluation to ensure gas concentrations remain below the LEL or that explosion risks are duly mitigated.
• Explosion Risk Mitigation: Predefined measures for reducing the risk of crankcase explosions have been introduced, ensuring greater protection against potential hazards.
• Engine Bearing Monitors: Engine bearing temperature monitors or equivalent devices are now classified as essential safety components.
• Comprehensive Documentation: Documentation detailing the effectiveness of the safety measures to prevent explosive conditions is to be provided my manufacturers and designers.