For the purpose of these Guidelines, unless otherwise stated
below, definitions are as defined in SOLAS chapter II-2.
1.3.1Accidents mean uncontrolled events that may entail the
loss of human life, personal injuries, environmental damage or
the loss of assets and financial interests.
1.3.2Certified safe type means electrical equipment that is
certified safe by a recognized body based on a recognized
standard1. The certification
of electrical equipment is to correspond to the category and
group for methane gas.
1.3.3CNG means compressed natural gas.
1.3.4Control stations mean those spaces defined in SOLAS
chapter II-2 and additionally for these Guidelines, the engine
1.3.5Double block and bleed valve means a set of three
automatic valves located at the fuel supply to each of the gas
1.3.6Dual fuel engines mean engines that can burn natural
gas and fuel oil oil fuel simultaneously or operate on oil fuel
or gas only.
1.3.7Enclosed 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
1.3.8ESD means emergency shutdown.
1.3.9Explosion means a deflagration event of uncontrolled
1.3.10Explosion 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
1.3.11Gas means a fluid having a vapour pressure exceeding
2.8 bar absolute at a temperature of 37.8°C.
1.3.12Hazardous 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
- 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.
- 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.
- 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
1.3.13Non-hazardous area means an area which is not
considered to be hazardous, i.e. gas safe, provided certain
conditions are being met.
1.3.14High-pressure piping means gas fuel piping with maximum
working pressure greater than 10 bar.
1.3.15IEC means the International Electrotechnical
1.3.16IGC Code means the International Code for the
Construction and Equipment of Ships Carrying Liquefied Gases in
Bulk, as amended.
1.3.17LEL means the lower explosive limit.
1.3.18LNG means liquefied natural gas (refer to 1.3.22).
1.3.19Main 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.
1.3.20MARVS means the maximum allowable relief valve setting
of a gas tank.
1.3.21Master 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.
1.3.22Natural 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).
1.3.23Open 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
1.3.24 Organization means the International
Maritime Organization (IMO).
1.3.25Risk 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.
1.3.26Recognized 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.
1.3.27Safety management system means the international safety
management system as described in the ISM Code.
1.3.28Second 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.
1.3.29Semi-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
1.3.30Single gas fuel engine means a power generating engine
capable of operating on gas-only, and not able to switch over to
oil fuel operation.
1.3.31SOLAS Convention means the International Convention for
the Safety of Life atSea, 1974, as amended.
1.3.32Source of release means any valve, detachable pipe
joint, pipe packing, compressor or pump seal in the gas fuel
1.3.33Tank room means the gastight space surrounding the
bunker tank, containing all tank connections and all tank
1.Refer to IEC 60079 series, Explosive atmospheres and IEC
60092-502:1999 Electrical Installations in Ships - Tankers -
2. See also definition in IEC
3. Refer also to the area classification
specified in Sec. 2.5 of IEC 60079-10-1:2008 Explosive
atmospheres - Part 10-1: Classification of areas - Explosive
4. Refer also to IEC 60092-502:1999 Electrical Installations in
Ships - Tankers - Special Features.