Central control room

A central location where instmment leads are short is preferred. In modem faciHties with distributed control systems, all units are controUed from a central control room with few operators. Only a few roving operators are available to spot trouble. It is desirable to deep process equipment a minimum of 8 m away from the control room. Any equipment and hydrocarbon-containing equipment should be separated by at least 15 m if possible. Most control rooms are designed with blastproof constmction and have emergency backup power and air conditioning. The room is pressuri2ed to prevent infusion of outside air that may have hydrocarbon content in the explosive range. 

In the CPI, the most extensively studied human-machine interface is in the central control room in automated plants where plant information is displayed on visual display units (VDUs) and appropriate control actions are made by the operating team. In the case of a highly automated plant, the primary role of the human is to respond to unexpected contingencies such as plant states that have not been anticipated by the designers of the automatic... 

The term control panel refers to the instrumentation console in a central control room through which process information is communicated to the process worker and via which the worker changes the state of the process. This category includes display elements such as chart recorders, bar indicators, dials, and modem VDU-based systems together with control elements such as buttons, switches, track balls and mice. The control panel is the human-machine interface (see Chapter 2) that has traditionally received the most attention from human factors specialists. 

The most likely means of rectifying the very high workload and error rates which are likely to occur, would be to make use of the VDUs in the control room to provide important information in a centralized location, perhaps also in certain cases to effect control actions. This would be especially useful in one of the platform control rooms, since it was never intended to be a centralized control room, and there were therefore many information limitations which could probably only be compensated for by providing VDU information. 

Stop, start, emergency stop and speed controls are grouped adjacent to the engine, and the machine is usually equipped with instrumentation for monitoring its safe operation. Very often, a centralized control room is provided, particularly when there are a number of units in operation. Typical signals monitored and recorded remotely are ... 

Manufacturers now offer as standard microprocessor-based control systems as part of their gas turbine generator set. The set can therefore be controlled and monitored from panels adjacent to the machine or, if required, remotely from a central control room. In combined-cycle installations, the system would be linked into the... 

In these kind of facilities, the DO level is measured very frequently to ensure compliance and may often be measured periodically in real time, with the results automatically forwarded to a system management monitor located in a central control room. 

The latest designs for onshore installations cater for a centralized control room, well distanced from the operating facility with sub control areas as part of a distributed control system (DCS). The sub-control areas are closer to the processes but contain fewer personnel and process control systems for the overall plant, so the overall risk level for the facility from a major incident is lowered. The outlying control buildings (sometimes referred to as PIBs or SIHs) still need to be sited against impacts from explosions and fires. 

Control rooms serving more than one process unit do not present unique hazards when considering the proper location of the building. However, they can significantly increase the size of a loss because of their multiple uses. For example, an incident in one unit could damage the central control room and impact the ability to operate other units. The business interruption financial impact is likely to far outweigh the actual damage repair costs. 

A tremendous cost savings is realized by the multiplexing of signals due to the elimination of many multi-conductor cables and thousands of field terminations. Also, because the PCMs are remote from the central control room, they can be installed in the equipment modules. This means that each equipment module can be virtually stand-alone in terms of electrical and control systems, thus allowing almost complete prefabrication in the fabrication yard the only remaining field work is connecting to the data highways. 

If the DCCS is required to replace an existing control system (i.e. if the plant is being retrofitted) then the microcontrollers will normally be located in the central control room (CCR). In this case, the distribution features of the DCCS will not be fully utilised and the significance of the digital data highway (DH) will also be reduced. 

The layout suggested for the chemical plant complex includes a central control room to operate all three plants. Administration, laboratory, and workshop areas are also common. The nitric acid plant is small, occupying less than 1 hectare. There is space on the 1 hectare plot for inclusion of a second parallel process train for possible future expansion. 

It features the three chemical processes flowing approximately one to the other. The joint administration and workshop facilities are located in the south-western corner of the plant. There is a central control room for all operations, and the rail link is extended into the despatch area. 

As technology progresses the safety of man-machine systems depends more and more on the quality of the human component (operator). This fact is very obvious in transportation, where the operator (driver) is formally and actually in control of his or her vehicle. In aviation, however, a strong trend towards software control of the aeroplane is already becoming dominant, forcing the operator (pilot) primarily into the role of supervisor or monitor of the automatic control system and into that of trouble-shooter in case of (technical) failure. In this respect a cockpit crew is facing the same situation as for instance a shift of operators in the central control room of a completely computerised chemical process plant. 

They controlled this highly automated aromatics plant by supervising the process from a Central Control Room (CCR) equipped with visual display units (so-called computer screens) as the human-machine interface. The five shifts of operators, at that time, had been working for about 16 years (approximately 5 million man hours) without a single Lost-Time Injury case, which meant an excellent safety performance according to that, standard. 

The incident took place at a Central Control Room (CCR) panel controlling a socalled Hydrogen Concentration Unit (HCU), A sudden change in the flow of the feedgas to the HCU triggered an alarm, in the control room which was subsequently detected and interpreted by the operators responsible for this unit in a correct and timely fashion their appropriate corrective actions resulted in preventing a costly trip (e.g. automatic shut-off) of the entire unit. 

IPC systems continue to offer advantages to pharmaceutical manufacturers in providing access to data on the shop floor, hazardous areas, and other hostile environments. IPCs are flexible and allow manufacturers the option to implement a central control room based system or a distributed plant based system. Both options are in use. 

Laboratories, analytical equipment, offices, canteens, changing rooms, central control rooms ... 

Figure 5. Layout of the pyrolysis plant (1) tires stock yard (2) shredding plant (3) pyrolysis plant (4) central control room (5) carbon black plant (6) storehouse ...

All equipment is controlled and under observation from the central control room. 

These systems are linked, monitored, and controlled through an advanced process management system operated from a central control room. 

The central control room provides surveillance and direction for all phases of TOCDF activities. It is kept at a higher positive pressure to prevent the possibility of any agent entering it, and the air intake is doubly filtered. Several consoles Une the room, each with two advisor screen monitors, two closed-circuit TV monitors, and a keyboard through which commands are entered to control plant operations. Redundant computers, software, and plant instrumentation ensure that continuous realtime control is maintained. 

The product composition, i.e. the proportion between protein and lactose in the final product, may be controlled from the central control room. Thus the factory is able to produce protein powder with compositions varying from approx. 35% protein of total solids to approx. 85% protein of total solids. The first mentioned is a product with a composition like cheap skim-milk powder, whereas the latter is an expensive product used for baby-food and dietetic food. 

The system and other areas around that plant are electronically controlled and monitored at the central control room. With the 2,304 trays of charcoal, the air ventilation system is designed to provide every hour up... 

A central control room from which all major controls are operated typifies modern chemical plants. This room houses the control equipment and operation, thus acting as the brain of the processing plant.) It should be designed for comfortable and pleasant working conditions. 

During an emergency the personnel should be able to access portable lamps and torches. These should be located adjacent to exit doors, in operational rooms, plant rooms, emergency accommodation areas, OlM s offices, central control room and muster areas. They should be provided with charger units and be suitable for zone 1 hazardous areas, and be capable of operating for at least five hours. 

Note 2 The lighting level in the central control room can be arranged to be wholly or partly adjustable so as to minimise glare and eyestrain whilst operating visual display units (VDU) or man-machine interfaces (MMl). 

Failure of any of the navigation lights can be indicated in the central control room and in the radio room. 

In the event of failure of the main white lights control equipment, control should automatically be transferred to the secondary system, which would cause the secondary and the main lights to flash in synchronism, and generate an alarm in the central control room and the radio room. 

The secondary and subsidiary lights can be equipped with an automatic lamp changer or multiple filament bulb. This provides a minimum of one standby lamp or filament which will be automatically activated in the event of a filament failure. Filament failure should produce an alarm in the central control room and the radio room until a defective bulb is replaced. 

Both types of work are undergoing considerable change. In postindustrial societies, assembly work in its classical sense (Taylor, 1923) is being modified in order to allow more flexibility in production systems and more individual control and responsibility (e.g.. Wall Martin, 1987). Supervisory monitoring is being transformed by computerized control systems that tend to diminish requirements for activity by the operator and confine him or her to centralized control rooms at a distance from the actual production process. 

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