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 6, 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 6, Ch 1, 3.3 Physical environment are to be complied with.
3.1.3 The
requirements of Pt 6, 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 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.
3.3.3 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 the operator is to be alerted when they
occur.
3.5.2 Means
are to be provided to correct wrong inputs or commands rapidly and
safely.
3.5.3 Assistance
is to be provided to the operator to recover from operator 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 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 system 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 (all parts): Graphical symbols
for diagrams. 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 6, 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 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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