NEW BUILDING FOR 3YA

Press, Volume XCVIII, Issue 28822, 17 February 1959, Page 16

NEW BUILDING FOR 3YA

Sound-Proofing Experiments

The reconstructed 3YA building will probably be one of the first new broadcasting studio buildings to apply lessons learnt from a recent series of experiments in Wellington. This point was made by Mr F. N. Blackwell, of the mechanical engineering division of the Ministry of Works, Wellington, during the first business session at the New Zealand Institution of Engineers’ conference yesterday. Presenting a technical paper on the proposed Broadcasting House building for Wellington, Mr Blackwell described a series of experiments on sound-proofing carried out by a team of his department’s building services engineers and Broadcasting Department officers. Close contact with this work was maintained by the Christchurch private architect and engineers designing the 3YA work and the Government Architect.

Design of broadcasting studio buildings brought many new problems for the heating and ventilating engineer, Mr Blackwell said. Air conditioning and its associated noise difficulties were both fairly new to this country and considerable research was needed to meet the needs of radio. Sealing Of Studios To prevent entry of noise, Broadcasting House was designed with a central concrete core, the only openings to which were through soundproof doors. Around this core were the office blocks and the recordings library, surrounded by the now familiar glass-curtain wall. Within the core were qll the studios and most of. the control suites, all of which would have to be air conditioned, and most of which would be occupied during all hours of broadcasting. AU the studios were thus completely sealed, and to maintain an atmosphere that would appearnormal they would have to he supplied with air whose temperature, humidity, movement and cleanliness were all controlled. To do this would require two ventilating plants and eight air conditioning plants comprising filters, fans, heating and cooling coils and equipment for varying the humidity. Air conditioning would operate automatically, 1 as set from a central panel, to either winter or summer conditions. Noisy Fans Fans had to be used to distribute the air to the room, and unfortunately • these were very noisy in relation to studio requirements. Special precautions had to be taken to reduce fan noisete and any other noises until the sound - proofing standard reached jn the air conditioning system was as high as that in the building structure, Describing the Wellington experiments, Mr Blackwell said that 24-foot lengths of air conditioning duct were each lined with various materials including slagwool in rigid and semi-rigid forms, limpet asbestos and New Zealand-made softboard. A loudspeaker was placed at one end of the duct and a microphone was moved through It on a track away from the speaker. Noise level was measured in decibels every six inches, the results were plotted on a graph, and the mean noise attenuation a foot was calculated. Slagwool was found to give the best results. The Broadcasting Service, Mr Blackwell said, had decided- to build Broadcasting House to as high a standard as was now possible so that it would be adequate for many years. It should be comparable with any up-to-date overseas broadcasting institution.