April_1965 — Page 38

C STATION

A STATION

ELECTRIC

scht.

PLANT

| CIRCULATION MATER

PULAR MOUSE

MACKIE S

STATION

ROAD

NOSNHor

ф 4 ф

WHARF

LANG

No # BO

GORBY

ROAD

1000 FON

FUN, DE FARK

ROAD

2140 TON

PT

WOOD

ROAD

future 120 MW development to the south, if required.

A permanent pumphouse is being constructed offshore in two stages, the main pumphouse being construct- ed inside a sheet pile confferdam, 50 ft. x 40 ft. x 30 ft. deep. When com- pleted it will replace the temporary pumphouse to provide all circulating water for the 'A' and 'C' stations.

No. 3 Larsen sheet piles in prior to prior to dewatering

Permanent pumphouse cofferdam.

Shuttering to turbine blocks for 80 MW sets

70

Buildings

IS

The three main buildings have steel frames. Over 1,200 tons of steel was used. The turbine and boiler houses are clad in 6in. reinforced concrete walls and the switchgear house fully encased in concrete, with block wall infill panels. Dimensions of the boiler house are 190 ft. by 96 ft. by 120 ft. high.

The superstructure will contain over 4,000 cu. yd, of in situ concrete, over 75 per cent. being in the switch- gear house.

To withstand the vagaries of Hong Kong's climate special roofing was designed for the boiler and turbine houses. Of Robertson Thain manu- facture, it is based on a light gauge steel platform and has a light reflect- ing soffit of off-white Galbestos.

The roof insulation is provided first by in. thick layer of fibrous insulation board. On top of this is a 12mm. thickness of Formica wood chipboard of .600 density, which was necessary to take the special point loading without the felt becoming depressed. Both boards are secured to the steel deck by screws as well as a bitumen adhesive. Waterproofing is provided by two layers of 30lb. asbestos based felt with a sanded finish, then a thicker 80lb. top layer with a mineral surface.

Sunshade

In order to maintain an even temperature and to protect the bitu- minous adhesives, a "sunshade" has been designed using in. thick, 2ft. Square Canton tiles. These are sup- ported and raised clear of the roof by in. thick, 4in. square concrete blocks, which are positioned under the centre and at the four corners of the concrete slabs, beneath which a passage of air can pass freely over the felt.

The spacings between the purlins vary from 6 ft. 6in. to 9ft. 9in, so the steel core of the Galbestos platform is constructed in 22 and 20 guage, in order to provide for a 15 lb. per sq. ft. superimposed live load, with a maximum deflection of 1/240th of the span.

Galbestos is a steel sheet which is protected from corrosion by an as- bestos envelope that has been bonded on both sides by molten zinc.

Nine 72in. throat roof ventilators, a feature of the station's skyline, are constructed from this same material. They are capable of removing 144,000 cu. ft. of air a minute, but to take

Far East Architect & Builder April, 1965