•Good working conditions.

•Ease of maintenance.

•Service experience.

Minimum overall cost

•Low capital cost.

•Low operating cost.

•Construction efficiency.

•Plant life.

•Service experience.

Within each of the major design objectives consider­ ation of the factors listed will also need to take into account the following:

•Statutory legislation.

•Environmental protection measures.

•Local resources and expertise available.

•Siting restraints.

The role of the designer is to evaluate these factors and arrive at the optimum design for a given proposal. Although in control of some parameters and not others, the designer is required to undertake the

engineering anil cost optimisation studies within (he limits of imposed constraints to meet the project objectives.

The following sections of this chapter deal with basicstation and plant layout from a CEGB viewpoint. Other volumes discuss in more detail the specific technical considerations relating to the design of plant for CEGB power stations.

5 Plant operation

The ability of station staff to efficiently manage the plant operation depends not only on the plant and equipment specifications but also on the layout. The development of main lines of communication and ma tenance access throughout the plant are a fundamen layout activity and need to be established at an early stage in the conceptual design of the station.

Personnel movement around the station can be established by assessing the relationship between th main permanently-manned areas of the station and t major plant items, andbetween the manned areas themselves. Main personnel assembly points are like to be:

• Administrative offices.

•Staff welfare and amenities centre.

•Workshops, work planning and stores centre.

•Main control room.

•Subsidiary control rooms such as for coal and ash handling plant.

•Laboratories.

All of these centres must service each of the installed generating units equally and provide for efficient and rapid personnel movements between centres where an important interrelationship can be established.

Reviews of personnel movements within operational stations of the CEGB have enabled these factors to be evaluated and station layouts developed which promote economic and efficient operational practices. Essen­ tially, these studies have shown the benefits of estab­ lishing a station management centre where all major activities are grouped together, apart from those

Plant operation

directly involved with plant monitoring and control such as the main and subsidiary control rooms.

These centralised facilities are positioned as far as possible to meet the needs of the site overall, and Chapter 1 Section 3 reviews their location in relation to the principal movement sequences for both station personnel and vehicles.

The position of the station central control room (CCR) is of high importance because it is the centre of plant monitoring and control. It needs to be located in an area where it is central to all unit operations, yet accessible during, but secure against, any major inci­ dent however unlikely.

The CCR may be at the centre of the station at oper­ ating floor level, typically on the boiler house side in the mechanical annex or between boilers, or on the side of the turbine house remote from the boilers. This latter position has been adopted on many multi-unit stations of the CEGB as illustrated in Figs 2.16 and