BUT —THE GLASS WAS ONLY CRACKED GLASS Georgian Wired Glass stays put in frames 15 feet from blitzed building 1, 2 and 3. Advertiser Pilkington Bros., Ltd. Agents F. C. Pritchard Wood and Partners Ltd. USU41 CH4NNEW 4. AdvertiserCapper, Pass and Son Ltd. Agents Alfred Pemberton Ltd. 5. Advertiser Concrete Ltd. Agents W. H. Emmett Co., Ltd. 6. Advertiser Haywards Ltd. Agents Braithwaite and Miller, Ltd. 7. Advertiser Cement and Concrete Association. Agents Erwin, Wasey and Co., Ltd. Artist Kenneth Petts. Time anJ 4g»ui (hat remark made when people h. Glass t-cnMs on be iKed for ARP wort Glass i»n we have been brought up to believe since the last wo new powers and it is now a structural material, tough and ran rem, bias, cm ARMOURUGHTGlasi Ixw« i the fragile, flimsy thing THERE IS OFFICIAL PROOF of tha resisting powers of areas of glass bricks in light frameworks of reinforced concrete. This will be found in A.R.P. Memorandum No. 12, issued by H.M. Stationery Office. You will find it under Goncral Notes, No. 3, sub-section (o), page 20. The official support for the powers of resistance of •Armourlight glass lenses appoars In Structural Oefenco, A.R.P. Handbook, No. 5, chapter 6, section 6. 2. THIS photograph was taken from inside some burned-out premises which adjoined a building glazed with Georgian Wired Glass in metal frames. Although a distance of 10 to 15 feet separated the two buildings the Wired Glass, although cracked, remained intact in the window frames. THE WAR GLASSES Wired Glass js one of the war glasses with special powers of resistance. There are also other glasses and glass units which can give extra strength and excellent service in war-time structural work and here are some facts about their properties I. ARMOURPLATE GLASS Armouri'I.atk Glass has special powers of resistance to shock and impact, and to high temperatures. It is produced in thicknesses ranging from in. to It in. Its resistance to severe impact is five to six times that of ordinary Polished Plate Glass of the same thickness. When broken, this glass disintegrates into innumerable fragments neither large nor sharp enough to cause serious injury. It does not splinter, and possesses 10 the full the transparency, lustre, and llatncss of ordinary Polished Plate Glass. In connection with oihcial tests with 500-1,0(10 11». boinhs bursting at distances of So ft. or more, A.R.P. Handbook N»>. 5 Structural Defence, states, J-in. toughened glass,* solid or hollow building lenses or gl iss bricks set in concrete frames are highly resistant to blast," A.R.P. Memo. No. 12—"Aims in Window Pro- Assuming that glass is likely to be broken, window protection shotila be devised (u) to prevent damage from flying pieces of glass (ft) to exclude weather (wind and rain) (c) to act as obscuration in certain cases. Wired Glass will provide (a) and (ft). When used in conjunction with shutters it will also provide (c) inasmuch as the glass remains in the frame even though cracked, thus permitting the shutters still to be used during black-out hours with natural light still available in the daytime. Wire reinforced glass is a fire retardativc and will prevent the spread of fire. It has been approved by the British Fire Prevention Committee's standards Specification B. The London County Council has approved its use as a fire-resisting material. A department for Technical Problems This advertisement is issued by Pilkington Brothers Ltd. Our Technical Department, at St. Helens, Lancashire, is always available for consultation on the use of glass under present conditions, in A.R.P. work, and in any form of structural work. The toughened glass referred to is Armourplate." 2. "ARMOURPLATE" LENSES Toughened Lenses have been specially manufactured for fixing into concrete, and provide approximately twenty times greater resistance to impact as a similar lens in ordinary annealed glass. Official tests have proved that they are highly resistant to blast pressure. In addition, they provide full protection against an incendiary bomb burning on the surface of the lens. 3. INSULIGHT GLASS BRICKS; These are hollow glass units made in two halves arul scaled together, and are designed for use in vertical walls. Glass bricks arc laid in the same way as ordinary bricks, but being a non-load bearing unit they should Ik- regarded as a panel within a structure. Recent iKiiubing has shown that they arc highly resistant to blast pressure, and, as a result of a test at the Building Research Station Fire Testing Station they have been - classified Grade I) under the conditions of the British Standard definitions No. 47H, as a lire resisting building 4. WIRED GLASS This is a well-known type of glass, but its efficiency, especially in war-time, is not perhaps fully appreciated. There have been certain references in A.R.P. publica tions on the effectiveness of wire netting placed over windows as a measure of protection, but in wired glass tlie wire netting is actually embedded and firmly fused into the middle of the glass itself. In the former case it is highly probable the blast will break the glass, the fragments become dislodged, and the wire netting may remain in the aperture the aperture itself, however, will l>e left fully open to the weather. Wire rciiforced glass, on the other hand, is highly resistant to blast pressure, iuid although the glass may be cracked, the wire holds it together as a complete panel and, except in cases of extreme severity, remains in the window opening. A.R.P. Handbook No. 5"Structural Defence," page 56 Glass reinforced internally with wire netting offers considerable resistance to blast. A.R.P. "War-time Lighting Restrictions for Industrial and Commercial Premises," page 9: If glass is essential, the substitution of plain glass by wired glass should be considered, especially when repairs are being made in the ordinary course. War-time Building Bulletin No. I"Treatment of Windows," page 4: It should Ik- noted that it is considered desirable to use Wired Glass whenever possible, since this has la-en found, by experiment, to offer high resistance to blast from a nearby high-explosive bomb. 104

Modern Publicity en | 1941 | | page 108