IGF Code - Simplified

The IGF Code: Ensuring Safety for Low-Flashpoint Fueled Ships • The IGF Code was adopted via Resolution MSC.391(95) on 11 June 2015. • It took effect on 1 January 2017, upon the entry into force of amendments to SOLAS Chapters II-1 and II-2. • It applies to ships to which Part G of SOLAS chapter II-1 applies. • Contracting Governments may also consider its voluntary application to cargo ships of less than 500 gross tonnage using these fuels, where practicable. The Goal-Based Approach: Safety and Environmental Protection Primary Goal (Chapter 3.1): • To provide for safe and environmentally-friendly design, construction and operation of ships and their installations using gas or low-flashpoint fuel. Basic Philosophy: • To provide mandatory provisions for the arrangement, installation, control, and monitoring of machinery, equipment, and systems using low-flashpoint fuel. • This is done to minimize the risk to the ship, its crew, and the environment. • The philosophy utilizes the goal-based approach (MSC.1/Circ.1394). Key Functional Requirements (Chapter 3.2): 1. Safety Equivalence: The safety, reliability, and dependability of the systems must be equivalent to that achieved with new and comparable conventional oil-fuelled main and auxiliary machinery. 2. Risk Mitigation: The probability and consequences of fuel-related hazards must be limited to a minimum through arrangement and system design (e.g., ventilation, detection). 3. Unacceptable Power Loss: The design must ensure that safety actions taken due to gas leakage do not lead to an unacceptable loss of power. 4. Single Failure Criterion: A single failure in a technical system or component shall not lead to an unsafe or unreliable situation. 5. Current Scope: The current version of the Code primarily includes regulations to meet the functional requirements for natural gas fuel (LNG/CNG). Regulations for other low-flashpoint fuels will be added later. Key Concepts: Areas, Fuels, and Emergency Systems Low-Flashpoint Fuel & Hazards: • Low-flashpoint fuel means gaseous or liquid fuel having a flashpoint lower than otherwise permitted under SOLAS regulation II-2/4. • Examples covered: Liquefied Natural Gas (LNG) and Compressed Natural Gas (CNG). • Hazardous Area: An area where an explosive gas atmosphere is or may be expected to be present, requiring special precautions for equipment. • LEL (Lower Explosive Limit): Used to set alarm (20% LEL) and safety system activation (40% LEL on two detectors) thresholds. Fuel Containment System (FCS): • The arrangement for fuel storage, including barriers and tank connections. • Secondary Barrier: The liquid-resisting outer element designed to provide temporary containment of liquid fuel leakage and prevent the ship's structure temperature from dropping to an unsafe level. • Tank Connection Space: A space surrounding all tank connections and valves in enclosed spaces. • Bunkering: The transfer of liquid or gaseous fuel into the ship's permanent tanks. Emergency Systems: • ESD (Emergency Shutdown): A system designed to automatically shut down machinery or non-safe equipment in the event of abnormal gas hazards. • Double Block and Bleed Valve: A set of two valves in series plus a third valve enabling pressure release from the pipe section between the two valves. This arrangement is critical for safety in the gas supply system [9.4.4]. Engine Room Safety: Gas-Safe vs. ESD-Protected Spaces The IGF Code mandates specific concepts for machinery spaces containing gas-fuelled machinery to minimize explosion probability: Feature Gas-Safe Machinery Spaces (Inherently Safe) ESD-Protected Machinery Spaces Gas Release Risk (Single Failure) A single failure cannot lead to the release of fuel gas into the machinery space. A single failure may result in a gas release into the space.