1.3 Definitions
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Statutory Documents - IMO Publications and Documents - Resolutions - Maritime Safety Committee - Resolution MSC.285(86) – Interim Guidelines on Safety for Natural Gas-Fuelled Engine Installations in Ships – (Adopted on 1 June 2009) - Annex – Interim Guidelines on Safety for Natural Gas-fuelled Engine Installations in Ships - Chapter 1 – General - 1.3 Definitions

1.3 Definitions

 For the purpose of these Guidelines, unless otherwise stated below, definitions are as defined in SOLAS chapter II-2.

  1.3.1 Accidents mean uncontrolled events that may entail the loss of human life, personal injuries, environmental damage or the loss of assets and financial interests.

  1.3.2 Certified safe type means electrical equipment that is certified safe by a recognized body based on a recognized standardfootnote. The certification of electrical equipment is to correspond to the category and group for methane gas.

  1.3.3 CNG means compressed natural gas.

  1.3.4 Control stations mean those spaces defined in SOLAS chapter II-2 and additionally for these Guidelines, the engine control room.

  1.3.5 Double block and bleed valve means a set of three automatic valves located at the fuel supply to each of the gas engines.

  1.3.6 Dual fuel engines mean engines that can burn natural gas and fuel oil oil fuel simultaneously or operate on oil fuel or gas only.

  1.3.7 Enclosed space means any space within which, in the absence of artificial ventilation, the ventilation will be limited and any explosive atmosphere will not be dispersed naturallyfootnote.

  1.3.8 ESD means emergency shutdown.

  1.3.9 Explosion means a deflagration event of uncontrolled combustion.

  1.3.10 Explosion pressure relief means measures provided to prevent the explosion pressure in a container or an enclosed space exceeding the maximum overpressure the container or space is designed for, by releasing the overpressure through designated openings.

  1.3.11 Gas means a fluid having a vapour pressure exceeding 2.8 bar absolute at a temperature of 37.8°C.

  1.3.12 Hazardous area means an area in which an explosive gas atmosphere or a flammable gas (flashpoint below 60°C) is or may be expected to be present, in quantities such as to require special precautions for the construction, installation and use of electrical apparatus.

 Hazardous areas are divided into zones 0, 1 and 2 as defined belowfootnote:

  • .1 Zone 0 is an area in which an explosive gas atmosphere or a flammable gas with a flashpoint below 60°C is present continuously or is present for long periods.

  • .2 Zone 1 is an area in which an explosive gas atmosphere or a flammable gas with a flashpoint below 60°C is likely to occur in normal operation.

  • .3 Zone 2 is an area in which an explosive gas atmosphere or a flammable gas with a flashpoint below 60°C is not likely to occur in normal operation and, if it does occur, is likely to do so only infrequently and will exist for a short period only.

  1.3.13 Non-hazardous area means an area which is not considered to be hazardous, i.e. gas safe, provided certain conditions are being met.

  1.3.14 High-pressure piping means gas fuel piping with maximum working pressure greater than 10 bar.

  1.3.15 IEC means the International Electrotechnical Commission.

  1.3.16 IGC Code means the International Code for the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk, as amended.

  1.3.17 LEL means the lower explosive limit.

  1.3.18 LNG means liquefied natural gas (refer to 1.3.22).

  1.3.19 Main tank valve means a remote operated valve on the gas outlet from a gas storage tank, located as close to the tank outlet point as possible.

  1.3.20 MARVS means the maximum allowable relief valve setting of a gas tank.

  1.3.21 Master gas fuel valve means an automatic valve in the gas supply line to each engine located outside the machinery space for gas-fuelled engines and as close to the gas heater (if fitted) as possible.

  1.3.22 Natural gas means a gas without condensation at common operating pressures and temperatures where the predominant component is methane with some ethane and small amounts of heavier hydrocarbons (mainly propane and butane).

  1.3.23 Open deck means a deck that is open on both ends, or is open on one end and equipped with adequate natural ventilation that is effective over the entire length of the deck through permanent openings distributed in the side panels or in the deck above.

  1.3.24 Organization means the International Maritime Organization (IMO).

  1.3.25 Risk means the expression of the danger that an undesired event represents to persons, to the environment or to material property. The risk is expressed by the probability and consequences of an accident.

  1.3.26 Recognized standards means applicable international or national standards acceptable to the Administration or standards laid down and maintained by an organization which complies with the standards adopted by the Organization and which is recognized by the Administration.

  1.3.27 Safety management system means the international safety management system as described in the ISM Code.

  1.3.28 Second barrier means a technical measure which prevents the occurrence of a hazard if the first barrier fails, e.g., second housing of a tank protecting the surroundings from the effect of tank leaks.

  1.3.29 Semi-enclosed space means a space limited by decks and or bulkheads in such manner that the natural conditions of ventilation are notably different from those obtained on open deckfootnote.

  1.3.30 Single gas fuel engine means a power generating engine capable of operating on gas-only, and not able to switch over to oil fuel operation.

  1.3.31 SOLAS Convention means the International Convention for the Safety of Life at Sea, 1974, as amended.

  1.3.32 Source of release means any valve, detachable pipe joint, pipe packing, compressor or pump seal in the gas fuel system.

  1.3.33 Tank room means the gastight space surrounding the bunker tank, containing all tank connections and all tank valves.

Parent topic: Chapter 1 – General
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