CONTENTS Foreword PART I Guidelines for Inert Gas Systems (MSC/Circ.282 as amended by MSC/Circ.353 and MSC/Circ.387) PART II Provisions for Application 1 1974 SOLAS Convention 2 1978 SOLAS Protocol 3 1981 Amendments to the 1974 SOLAS Convention 4 1983 Amendments to the 1974 SOLAS Convention 5 Clarification of inert gas system requirements under SOLAS 1974, as amended (MSC/Circ.485) PART III Provisions of Technical Requirements 1 1974 SOLAS Convention 2 Amendments to the 1974 SOLAS Convention 3 1983 Amendments to the 1974 SOLAS Convention PART IV Regulations for Inert Gas Systems on Chemical Tankers 1 Regulation for insert gas systems on chemical tankers (resolution A.567(14)) 2 Draft amendment to regulation II-2/55.5 of the International Convention for the Safety of Life at Sea, 1974, as amended (resolution A.566(14)). PART V Application of Requirements for Inert Gas Systems for Oil Tankers by Port Authorities and Terminal Operators (MSC/Circ.329) PART I GUIDELINES FOR INERT GAS SYSTEMS (adopted by the Maritime Safety Committee at its forty-second session and amended at its forty-eighth and fiftieth sessions) CONTENTS 1 INTRODUCTION 1.1 Purpose 1.2 Application 1.3 Definitions 2 PRINCIPLES 2.1 General 2.2 Flammable limits 2.3 Effect of inert gas on flammability 2.4 Sources 2.5 Quality 2.6 Methods of gas replacement 2.7 General policy of cargo tank atmosphere control 3 FUNCTION AND DESIGN CONSIDERATIONS 3.1 Description of an inert flue gas system 3.2 Function of inert gas scrubber 3.3 Design considerations for inert gas scrubber 3.4 Function of inert gas blowers 3.5 Design considerations for inert gas blowers 3.6 Function of nonreturn devices 3.7 Design considerations for nonreturn devices 3.8 Inert gas distribution system 3.9 Design considerations for valves and pipework in inert gas systems 3.10 Gas pressure regulating valves and recirculating arrangements 3.11 Arrangements for inerting, purging and gas-freeing (regulation 62.13) 3.12 Isolation of cargo tanks from the inert gas deck main (regulation 62.11) 3.13 Liquid-filled pressure/vacuum breakers 3.14 Instrumentation and alarms (regulation 62.16 to .19) 3.15 Effluent and drain piping 3.16 Seawater service 4 OPERATION OF INERT GAS PLANT 5 APPLICATION TO CARGO TANK OPERATION 5.1 Inerting of tanks 5.2 Discharge of water ballast 5.3 Loading 5.4 Loaded condition 5.5 Cargo transfer and cargo sampling 5.7 Ballasting of cargo tanks 5.8 Ballast condition 5.9 Tank cleaning