Civil Engineering Reference
In-Depth Information
Fig. 15.1
Diagrammatic
representation of
operating philosophy
Schedule of
requirements for
tunnel installations
Integral safety
plan
Operating philosophy
Environmental analysis
Task analysis
Operating analysis
Monitoring and
operating design
The operating design; as much automatic handling as possible
by the operating system
An important brief for the operating design of the Westerschelde Tunnel was
the fact that it is difficult for an operator to take the right decision at every
moment and in every circumstance. It is human to err and that is why the tak-
ing of crucial decisions should be handled automatically by the operating
system as much as possible, or - if this is not possible - to be recorded in
procedures. This is of particular importance because in general, a complex
situation could occur rather suddenly from a condition of relative calmness,
and generate a large number of detections in a short space of time, which
must be handled directly and effectively. This sudden transition from calm-
ness to 'major tension' increases the chances of human error.The equipment
available to the operator, however makes it possible for him to make unam-
biguous choices and where possible in a menu-like manner.
A large number of commands with a single button
Commands that are complex, which logically follow on to each other or
can be logically combined, are grouped into a group command as much as
possible which can be activated by means of a single 'push of the button'.
An example of this is the emergency button in which a large number of
commands are given simultaneously, including the releasing of the emer-
gency doors, the starting up of the fire extinguishing pumps, the activation
of (a section of) the tunnel ventilation and the increasing of the lighting
level. The simultaneously activated commands can each be separately
switched off in the normal manner, if necessary. The activated commands
are therefore indicated in a separate 'dialogue' on the monitoring screen.
This increases the operator's overview of the situation and gives him the
opportunity to withdraw unnecessary commands, if the situation in the tun-
nel is different to that originally thought it to be.
The operator is safe-guarded from mistakes
The operator is therefore safe-guarded against making mistakes. When he
takes a decision which could lead to serious consequences - the lowering of
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