October_1970 — Page 14

system provided by the suppliers was found to be inadequate to cope with the ambient temperature of the mains water supply. A heat exchanger was designed and manufactured locally to overcome this.

To ensure that the concentration of radioactive material in waste dis- charged into the public sewers was within acceptable limits, six-gallon cisterns were installed to all toilets

Third floor plan

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likely to receive radioactive waste and all waste from the isotope laboratories has been taken through balancing tanks to neutralise or reduce the con- centration of chemicals in waste water.

To cater for the electrical require- ments of the machine area a separate substation containing one 200 KVa 11KV/380V transformer and one 100 KVa 11KV/415V transformer was built. The 200 KVa transformer sup-

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plies only and directly through an air circuit breaker to the Betatron control rack installed in the Betatron machine

room.

The 100 KVa transformer supplies to a low-tension switchboard within the substation from which seven feed- ers were brought, all as independent supply, direct to the respective machine control centres.

Lighting and general power sup- plies for the treatment rooms are on a separate feed. Each treatment room has a warning light above the door, which operates when the machine is running and interlock switches are fitted on all the treatment room doors so that the machine cannot be operat- ed if the doors are open or not closed properly. The electrically operated doors are connected to the hospital emergency supply system so that the doors can be operated if normal supply fails.

Supervision of patients undergoing treatment on the Betatron and linear accelerators is by closed circuit telvi- sion, since the high energy levels make direct viewing difficult. Each of the three rooms has a wall-mounted televi- sion camera focussed on the treatment couch and two television monitors, one inside the room and one at the

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Front of the radiotherapy centre which is shown linked to the main north ward block, left. In the forefront is part of the site for the Tunku Abdul Rahman Neurological Sciences building

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Far East BUILDER, October 1970