No_6_April_1964 — Page 128

never-

que can produce a more even in situ filling with fewer voids, but theless considerable skill is still neces- sary to ensure as good fill,

Another potential application of some interest is in spraying an in situ foamed layer of insulation on to the underside of skin roofs. Although this application has not been develop- ed to any great extent, one case known where such an application

of foam, on corrugated asbestos cement sheets, has appeared to be quite suc- cessful although the cover was rather uneven in appearance. A thin under- coat of rather dense foam was first applied to provide a base for the top coat which could then be built up to the desired thickness. As a fairly im. permeable outer skin was formed on both coats, and because the foam had a closed-cell structure, it is probable that the water-vapour transmission of the foam would be low enough to prevent condensation except in severe conditions, and if necessary a ‘cocoon' or paint film could be applied to im- prove this. One drawback of the process is that. because of the slightly toxic nature of one component

of the foam. it is necessary to evacu- ate the building during spraying and for the operative to wear a protec tive suit. with a helmet. In addi- tion, the visor is likely to become rapidly obscured by splashes from the spray gun. resulting in a rather intermittent spraying process. How- ever, provided that a satisfactory technique can be worked out

for applying the material. the good thermal insulation and low vapour transmission of the foam layer. to- gether with good adhesion to the sur- face. should provide a finish that would appear satisfactory for many

industrial and agricultural applica- tions.

Foamed polyurethane is also used as the core in lightweight sandwich panels, where its adhesion to smooth surfaces is an advantage in the manu- facturing process. This application is referred to below.

EXPANDED EBONITE

Expanded ebonite has been avail- able on the market for longer than most cellular plastics and, though the high price limits its application in building. it has been used in a few specific applications. It has very low water vapour transmission and has been widely used in the insulation of cold stores and pipes carrying cold liquids. It can be used also as peri- meter insulation round heated floors. where high compression strength and low vapour transmission are an ad- vantage, but care must be taken ensure that it cannot become over- heated, since the upper working tem- perature limit is only 122°F. It is rarely used where it is exposed on the surface since it is dark coloured and not very attractive in appearance, and also gives off the unpleasant odour of hydrogen sulphide when cut. In more resilient forms it can also be used to fill expansion joints between slabs of concrete.

SANDWICH PANELS

to

Several of the rigid cellular plas- tics have been suggested for use in sandwich panels. where the interac tion of skin and core can produce considerable rigidity. Using suitable adhesives, sheets of plywood, plaster- board, asbestos cement and solid plastics, for example, can be stuck to

p.V.C..

the surfaces of polystyrene. phenol-formaldehyde or polyurethane foams to form panels for which num- erous advantages are claimed. It is also possible to foam polyurethanes between two skins to form such panels in one operation without the need for adhesives. Such panels certainly are light in weight and have good thermal insulating pro- perties but. unless the outer skins are quite massive, they provide little in- sulation against air-borne sound. The fear that uneven thermal movement will cause bowing is probably exag. gerated because. if the panels are firmly fixed. the flexibility of the foam is likely to accommodate any movement. These considerations apply also to doors, which are avail- able with expanded polystyrene cores. Sandwich panels of this type are widely used, but find a great deal of competition in internal partition- ing. They are used less for external cladding because of difficulties in jointing and the need to provide at- tractive weatherproof outer sur- faces. Another application for cellu- lar plastics that seems to have ad- vantages in large panel systems of construction is as an insulating lining for precast concrete panels. with lighweight inner skin fixed to the plastics foam. On the Continent many systems employ wall units con- sisting of expanded polystyrene sand- wiched between concrete slabs. While the economics of such systems may be open to question in the UK.. there is no doubt of the benefits of improved thermal insulation that they provide.

a

Prepared at the Building Research Station. Garston. Britain,

Crown copyright.

BUILDING PLANS APPROVED BY PENANG CITY COUNCIL

Plan No.

JANUARY, 1964.

Locality

11495 Lot 77(i) T.8.15. Amoy Lane 11496 Lot 581 T.8.9W, Perak Road.

Lot 343 T.8.21. Beach Street. Lots 850, 490, 849 and 995 T.8.12,

Jalan Deva Pada.

Lot 853 T.8.12, Jalan Deva Pada Lot 21(1) T.8.22. Prangin Road. Lot 147 T.8.4, Off Burmah Road

Daud Meah

Owner

Lim Eng Heong & Meoh

Teong Sar

Heng Wang Co. Ltd Ong Hoo Hong

Penang Buddhist Association Tung Leong Geok

11497 11498

11499

11501

11503

11504

11505

Lot 147 T.8.4, Off Burmah Road Lets 34(8) and 34(7) T.8.4.

Kelawei Road.

11567

Lot 150(x) T.8.1. Ayer Rajah

Road and Brown Road.

11509

Lots 110 and 111 T.8.1, Burmah

Road.

Yeap Hock Hin

Syed Mahdhar Syed Alwee

& Syed Abubakar. Syed Hydar bin Sahil Gaik Lean Investments

Madam Khaw Phaik Hong

Architect

T. G. Weng Raymond Khoo

Kee Yeap

G. L. Khoo

C. L. Khoo Ong Lean Cook T. C. Weng

T. C. Weng Ang Kheng Leng

R. Winthrop

Lim Soo Kok

Description

Two two-storey dwelling houses. Six two-storey shophouses.

Office block.

Seven two-storey terrace houses

Four terrace houses. Two-storey lock-up shop. Timber dwelling house.

Timber dwelling house. Two blocks of two-storey semi-detached houses. Compound house.

Bungalow.

122

THE HONG KONG & FAR EAST BUILDER—VOLUME 18, NUMBER 6