Section
3 Ergonomics of control stations
3.1 Objectives
3.1.1 In order
to take account of operator tasks at control stations, enhance usability
and reduce human error, the layout arrangements are to comply with
the requirements set out in Pt 16, Ch 1, 3.2 Control station layout.
3.1.2 In order
to establish a working environment that has minimum distractions,
is sufficiently comfortable, helps maintain vigilance and maximises
communication amongst operators at main control stations, the requirements
of Pt 16, Ch 1, 3.3 Physical environment are to be complied with.
3.1.3 The requirements
of Pt 16, Ch 1, 3.4 Operator interface apply to operator
interfaces for essential engineering systems located either locally,
remotely or within the main control room. The requirements are intended
to enhance the usability of systems and equipment, reduce human error,
enhance situational awareness and support safe and effective monitoring
and control under normal and abnormal modes of operation.
3.2 Control station layout
3.2.1 Control
stations are to provide sufficient space and access for the intended
number of operators in the expected operating conditions.
3.2.2 Local
control stations are to be positioned to minimise the risk of harm
to the operator.
3.2.3 Controls,
displays and indicators are to be both logically and physically grouped
according to their function.
3.2.4 Where
a function may be accessed from more than one interface, the arrangement
of displays and controls is to be consistent.
3.2.5 Frequently
used controls and displays are to be within easy reach and visible
to the operator from the normal working position.
3.2.6 Controls
and displays used infrequently and which may be used in an emergency
are to be clearly identifiable, clearly visible, easily accessible
and positioned to allow safe operability.
3.2.7 The relationship
of a control with a display is to be immediately apparent.
3.2.8 The relationship
of controls and displays with the equipment under control is to be
immediately apparent.
3.2.9 There
is to be adequate spacing between controls and between controls and
obstructions.
3.2.10 Controls
and their associated displays are to be located such that the information
on the displays can be easily read during the operation of the controls.
3.2.11 Indicators
related to the controls are to be visible during their operation.
3.2.12 Instruments
are to face the operator’s intended working position.
3.3 Physical environment
3.3.1 Control
stations are to be positioned, as far as practicable, away from, or
insulated against, sources of structurally transmitted vibration and
noise, such as ventilation fans, engine intake fans and other noise
sources.
3.3.2 In general,
noise levels are to comply with IMO Res. MSC.337(91) Code on
Noise Levels On Board Ships, and are to take into account IMO
Res. A.343(IX), Recommendation on Methods of Measuring Noise;
Levels at Listening Posts.
3.3.3 Where
provided, the heating, ventilation and air-conditioning system is
to be capable of maintaining the temperature between 18°C and
27°C.
3.3.4 The flow
of air from heating or air-conditioning systems is not to be guided
directly to the operator, or means are to be provided to adjust the
direction of airflow from those systems.
3.3.5 Lighting
is to be located to avoid glare from working and display surfaces,
and is to be flicker-free. Surfaces are to have a non-reflective or
matt finish.
3.3.6 Placement
of controls, displays and indicators are to consider the position
of light sources relative to the operator with respect to reflections
and evenness of lighting.
3.3.7 Where
a transparent cover is fitted over a control, display or indicator,
it is to be designed to minimise reflections.
3.3.8 The level
of lighting is to be sufficient to enable operation of user interfaces.
Lighting levels, in accordance with Table 1.3.1 Specific lighting levels, will be considered to satisfy this requirement.
Table 1.3.1 Specific lighting levels
| Work area
|
Ideal Lux
|
Minimum Lux
|
| General lighting
|
540
|
220
|
Control room consoles
(front)
|
540
|
320
|
Control room consoles
(rear)
|
325
|
110
|
| Local operating panels
|
540
|
320
|
| Remote operating panels
|
540
|
320
|
3.3.9 Seating
provided for use at control stations is to allow for varying height
and/or reach needs of operators. Seating arrangements are to minimise
the need for twisting and/or turning motions by the operator.
3.3.10 Physical
hazards, e.g. sharp edges, protuberances and trip hazards, are to
be avoided.
3.3.11 Sufficient
handrails or equivalent are to be fitted to enable operators to move
and stand safely in rough seas.
3.3.12 Work
surfaces are to be capable of withstanding oils and solvents common
to ships and are to be easy to clean.
3.4 Operator interface
3.4.1 The design
of the operator interface is to permit the satisfactory monitoring,
control and supervision of the machinery and equipment.
3.4.3 The response
of the machinery and equipment to operator input is to be consistent
between interfaces for the same function.
3.4.4 Visual,
audible or mechanical feedback is to be provided to indicate that
operator input has been acknowledged.
3.4.5 Functions
requested by the operator are to be confirmed by the displays on completion.
3.4.6 Indications
and documentation are to be in English or the language of the crew.
3.5 Controls
3.5.1 Operator
inputs are to be checked for errors, for example, out of range data
or incorrect actions, and alert the operator when they occur.
3.5.2 Means
to rapidly and safely correct wrong inputs or commands is to be provided.
3.5.3 Assistance
is to be provided to the operator to recover from operating errors,
for example, through advisory screens where the automation system
has this facility.
3.5.4 Operator
confirmation is to be provided for any control action that could affect
the safety of the ship, i.e. they should not rely on single keystrokes.
3.5.5 The purpose
of each control is to be clearly indicated. Where standard symbols
have been internationally adopted, they should be used.
3.5.6 The settings
of mechanical controls are to be immediately evident.
3.5.7 The means
of operation of mechanical controls is to be consistent with expectations.
3.5.8 Controls
or combined controls and indicators are to be distinguishable from
indicators.
3.5.9 Where
control is provided by touch screens, the size of the soft keys are
to be of a sufficient size for operation in areas where vibration
occurs or gloves are likely to be worn.
3.5.10 Where
virtual keypads/keyboards or dialogue boxes are used on touch screens,
they are not to obscure status or alarm areas of the display.
3.5.11 Keyboards
are to be divided logically into functional areas. Alphanumeric, paging
and specific keys are to be grouped separately.
3.5.12 Controls
that affect the safe operation of the ship should be arranged so as
to minimise the possibility of inadvertent operation.
3.6 Displays
3.6.1 The displays
and indicators are to present the operator with clear, timely and
relevant information.
3.6.2 Graphical
symbols and colour coding are to be consistent. The graphical symbols
of display functions are to be in accordance with a recognised International
Standard, for example, ISO 14617, Graphical symbols for diagrams (all
parts). Colour coding of functions and signals is to be in accordance
with a recognised International Standard, for example, ISO 2412, Shipbuilding
– Colours of indicator lights.
3.6.4 The display
of information is to be consistent with respect to screen layout and
arrangement of information.
3.6.5 Flashing
of information is to be reserved for unacknowledged alerts, or transient
states, for example, valve moving.
3.6.6 The functions
supported by a display are to be clearly indicated. For displays that
can support multiple functions, it is to be possible to select the
display associated with the primary function or an overview by a simple
operator action.
3.6.7 The operating
mode of the machinery and equipment is to be clearly indicated.
3.6.8 In general,
indications provided by instrumentation which are displayed digitally
are not to change more frequently than twice per second.
3.6.9 To indicate
an increasing value in a single direction, on a fixed circular scale,
the pointer is to move clockwise. If the pointer is fixed, the scale
is to move anticlockwise to indicate an increase in value.
3.6.10 To indicate
an increasing value on a horizontal linear scale, the pointer is to
move from left to right. On a vertical linear scale, the pointer is
to move upwards to indicate an increase in value.
3.6.11 The
pointer is not to obscure the numbers on the scale.
3.6.12 Alphanumeric
data, text, symbols and other graphical information is to be readable
from relevant operator positions under lighting conditions as specified
in Pt 16, Ch 1, 3.3 Physical environment 3.3.8. Character height in
millimetres is to be not less than three and a half times the reading
distance in metres and the character width is to be 0,7 times the
character height.
3.6.13 A simple
sans-serif character font is to be used in displays. In descriptive
text, lower case letters are to be used, where appropriate, as opposed
to capitals to improve readability.
3.6.14 Where
information related to the safe operation of machinery and equipment
is provided, it is to be continuously available to the operator.
3.6.15 Failures
are to be indicated in a clear and unambiguous manner. Sufficient
information is to be provided for the operator to identify the cause
of the failure.
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