175 / 648
Safety and environmental standards for fuel storage sites
Final report
173
Information and system interfaces for front-line staff
232 Control room design and ergonomics, as well as effective alarm systems, are vital to allow front
line staff, particularly control room operators, to reliably detect, diagnose, and respond to potential
incidents. They should comply with recognised good practice appropriate to the scale of the operation.
Guidance on human-computer interfaces
233 In the past, most control rooms consisted of hard-wired equipment laid out on large metal
panels and desks, which required the operator to patrol the panels, monitoring key plant variables,
adjusting set-points and operating equipment. These have now commonly been replaced by
computer screen based (‘soft-desk’) systems, through which the operator both views the plant
and operates it. In the majority of such cases there is no hard-wired facility at all. This is known as
a human-computer interface (HCI) (or human-system interface (HSI)).
234 In the fuel transfer and storage industry, there is a range of equipment still found, from hard-
wired panel-based equipment with a high degree of manual control, to computer-screen based
control systems with a high degree of automatic control. Refineries typically have computer-
screen based systems. However, most tank storage terminals do not, and the majority of control
actions are still carried out by the operator.
235 EEMUA 201 discusses the changing nature of control centres, and how these changes
have affected the role of the control room operator. It is the primary and authoritative industry
guide to HCIs, and is intended to help those involved in the design, procurement, operation,
management and maintenance of these systems. It includes material derived from cooperation
with the US-based Abnormal Situation Management Consortium (ASM). ASM publications should
be consulted where further information is required.
236 HCIs provide the vital means by which the operator obtains information on the state of the
plant, enters operational data, and by which any automatic control action can be overridden and
manual control of the plant be taken.
237 As plants have become more automated, the automatic system, rather than the operator,
performs the majority of the control actions. The operator tends to have a more reactive role, devoting
more time to analysing potential problems or dealing with shortfalls in performance. Major intervention
by the operator is only required when the plant moves away from its normal operating parameters.
238 Therefore a modern HCI is required to perform satisfactorily for two very different situations.
For most of the time the plant will be operating normally and the HCI must be designed to aid the
operator maximise plant efficiency, but when an abnormal situation arises the HCI must aid the
operator in returning the plant to normal operation as soon as possible.
239 Design of the system is crucial to the operator’s role, including the number of screens, the
design of displays, and the means of navigation around the system. The HCI to a process control
system is critical in allowing an operator:
to develop, maintain and use an accurate and up-to-date awareness of the current and likely
■
■
future state of the process; and
to interact with the system quickly and efficiently under all plant conditions.
■
■
240 To achieve this, the following categories of operation, in order of importance, need to be
considered:
Category 1: Abnormal situation handling, including start-up and shutdown.
■
■
Category 2: Normal operation.
■
■
Category 3: Optimisation.
■
■
Category 4: General information retrieval.
■
■