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ilp archive : journals

public lighting no. 30 vol. 8
July-September 1943 Conference Number (1)

Editorial p39
The Conference p39
The Conference was held in London on September 22nd and 23rd. It allowed many members to meet each other after a break of five years. The general tenor of the meetings was one of keenness and enthusiasm to get ahead with relighting of streets as soon as the opportunity became possible.
APLE: Conference

No Illuminated Barrage Balloons p39
A foolish idea, which found a ready following in the cheap Press, and more unfortunately with certain local government officials, that in the post-war period use should be made of Barrage Balloons for "high mounting" lighting. This was "exploded" by Mr. J. M. Waldram in his paper. By a series of demonstrations he was able to convince his hearers that apart from the colossal expense incurred for launching and maintaining an illuminated balloon barrage, the initial cost would stagger a financial Committee, and the uncertainty of such a system of lighting and the total lack of uniformity would condemn it.
Lighting: Future

Searchlights Too! p39
The possibilities of using searchlights for street illumination has found favour in some newspapers. The reflections of searchlights off clouds gives a soft "moonlight" appearance to the streets and if such a light could be guaranteed at all times, something could be said its favour. But who would want cloudy nights 365 days in a day?
Lighting: Future

Central Control p39
Daily Press reporters imagined they had "discovered" the solution to all black-out difficulties when they coined the magic words "master switch." Having learned that a certain town in the North had installed a system of central control for street lighting and A.R.P. services, they were quick to publish confused stories.
Lighting: ARP, Lighting: Control, Lighting: Future

Fifty Years Service p40
On Thursday, September 9th, Mr. George Keith, Chairman and Managing Director of Keith Blackman Ltd. was presented with a solid silver tray and gold watch chain to mark his completion of 50 years service.
Lighting: Personnel

Conference Numbers 1 & 2 p40
This issue and the next have been reserved for a full account of the Conference.
APLE: Conference

Some Familiar Faces Seen At The Conference p40
Picture of delegates at the conference.
APLE: Conference

Annual General Meeting p40
The President Mr. E. J. Stewart. M.A., B.Sc., F.I.E.S. (Glasgow) presided, supported by members of the Council. Minutes of last AGM (held on November 21st 1940?) were read and signed. The treasurer, H. C. Brown, presented his report which was accepted. A telegram was sent to the King. The Council's Report was read which reviewed the work of the Association during the War period and was adopted. The auditors, Messrs. Gundry Cole & Co. were re-elected. Mr. A. C. Cramb, director and secretary of the British Electrical Development Association, and President of the Association in 1927, wished to resign his membership due to his retirement - he was made an Honorary Member of the Association. All present stood for a second in silence in memory of all who had passed away - including Mr. C. H. Woodward (President 1938), Mr. W. Dundas and Mr. J. Taylor. The President then gave his address. APLE: Conference, APLE: Organisation, Lighting: Personnel

The Presidential Address p41
Summary of the The Presidential Address.
Lighting: ARP, Lighting: Authority Organisation, Lighting: Columns, Lighting: Education, Lighting: Floodlighting, Lighting: Future, Lighting: Lamps, Lighting: Levels, Lighting: Maintenance, Lighting: Management, Lighting: Materials, Lighting: Photography, Lighting: Signs, Lighting: Specifications and Lighting: Users

The A.P.L.E. Luncheon p48
On Thursday, September 23rd, there was a Reception and Luncheon at the Savoy Hotel, London. Col. Sir. Charles Bressey (Chief Engineer, Department Of Transport) stated that he was impressed with the unified control that existed in Glasgow compared with the position in London where there was such sub-divided control in almost every branch of administration. He hoped that members of the Association would come back with new vigour after the war, he looked forward to new methods and to something we had never seen before. He said that in the two years 1940-1942, with comparatively little traffic on the roads, there were no fewer than 7,334 deaths during the blackout.
In the Association's programme for the future, he had no doubt, that stress would be laid on the need for uniformity of street lighting. He hoped that many of the recommendations in the Departmental Committee Report of 1937 would be applied and that uniformity would be improved.
Everyone was looking forward to the renovation of our towns and cities and there would be room for very much better lighting than we had been used to.
Has it ever occurred to the Association to offer a prize to sculptors, artists and architects for a design or designs for a lamp-post which might be admired not merely by the layman and Alderman and Councillor, but also by artists and connoisseurs.
APLE: Conference, Lighting: Authority Organisation, Lighting: Future, Lighting: Health, Lighting: Safety, Lighting: Specifications and Lighting: Statistics

Street Lighting - Past, Present And Future by J. M. Waldram, B.Sc., A.C.G.I., F.Inst.P p49
Summary of the paper.
Lighting: Distribution, Lighting: Future, Lighting: Materials, Lighting: Lamps, Lighting: Theory

The Logic Of Street Lighting by P. Hartill, A.M.I.E.E., F.I.E.S. p52
The main object of street lighting is to provide road safety by night, because of the high rate of accidents that occur during the hours of darkness. The time has arrived when the provision of street lighting should not be limited by restricted allocation of funds, and prior to the war, the Ministry Of Transport were making grants towards the cost of new installtions on conditions that they compiled with the recommendations of the Final Report of their Departmental Committee. The war has given time to further study this report.
In the Final Report, paragraph 55, the view is expressed that "objects on the road at night are almost always seen in silhouette as dark objects on a bright background and that if other conditions, such as glare, remain unchanged, visibility will therefore be greater the higher the brightenss of the background and the lower that of the object." This may be fairly accepted as a statement of fact concerning average street lighting conditions. Detail can be regarded as being unimportant compared with the perception of outline, the motorist is mainly concerned with the presence and movement with an object, not its colour or texture. Until we can afford to illuminate the streets to provide the same clarity of vision as obtained in daylight we must be content with the more economical silhouette vision.
"It follows that the distribution of light from the fittings should be designed primarily to produce as uniform and high a background brightness as possible, subject to the avoidance of undue glare, whilst at the same time maintaining as high a contrast as possible between objects and their background. The background includes not merely the carriageway and footway surfaces, but also other surfaces, such as those of buildings or fences against which objects may be seen." The shape of the reflected area on the road surface depends mainly unpon the reflecting properties and inclination of the road surface. On a dry macadam road with polish it takes the form of a "T" - the wide area near the source produced by diffused reflection, and the tapering streak due to the specular component of the reflection. The brightness of the T-shaped area is dependent on: (1) the degree of diffusion afforded by the reflecting properties of the road surface, (2) the flux density of the incident light and (3) the intrinsic brilliance of the source.
If the road has a dry, matt surface, then the specular component of the reflected light will be inconspicuous and the brightness will be mainly due to the flux density i.e. the value of the illumination. On a wet, polished road with little diffusion, the streak of specular reflection will be very pronounced and the brightness will depend on the brilliance of the source.
The presence of streaks cause significant dark areas to appaer if the sources more than 200 feet ahead of the motorist appear to be widely separated - irrespective of their linear distance apart. This was a very common and undesirable feature of pre-war street lighting: objects were clearly visible only when silhouetted against the streaks and were indiscernible agaisnt the dark areas. One of the aims for satisfactory silhouette vision is uniformity of background brightness. "The angle subtended at the observer by sources appearing to him to be adjacent should not exeed a certain value if the production of dark areas is to be avoided." The brightness of pavements, fencing or buildings bordering the roadway usually have greater diffusing powers than the carriageway, their brightness depends on their illumination and reflection factor. It follows that to obtain uniformity of brightness across the whole width of the background, it is necessary that sufficient light should be emitted laterally from the sources.
It is interesting comparing Street Lighting After The War (D. G. Sandeman) which advocates the production of high road brightness by projecting high candle-power from sources at angles approaching the horizontal against the flow of traffic with Lateral Street Lighting After The War (F. F. Middleton) in which attention is drawn to the importance of providing adequate brightness at the sides of a thoroughfare. To produce satisfactory uniformity across the whole background with the type of light control advocated by Mr. Sandeman, sufficient light must be emitted laterally to the pavements, fencing and buildings, which must be light in colour and have a high reflection factor. Without favourable conditions the brightness of the carriageway will be excessive by contrast with the remainder of the background, and the system will tend to accentuate the non-uniformity, rather than improve the uniformity, of the background brightness.
Considering the problem from a motorist's point of view, it would generally be far safety to drive along the road where the pavement and fences were adequately lighting with no light on the carriageway, than along a road where these conditions were reversed. The carriageway itself is usually less than half of the total useful background, and any object, such as a pedestrian, would nearly always be at least partially silhouetted against the remainder. The motorist should be able to see a pedestrian approaching the carriageway from the side in good time to anticipate his movement.
The design of lanterns with optical control devices which magnify the candle-power in two vertical planes dates from the time when it was thought that uniform illumination on the carriageway, from sources at relatively large spacings, would give the best results - the aim was to provide as low a diversity of illumination as practicable. The aim now is to produce a low diversity of brightness, not only on the carriageway, but over the whole useful background. The logical procedure is to minify, rather than magnify, the candlepower directed along the carriageway, and re-direct the light thus saved to other areas, until the average brightness of the semi-specular streaks is more nearly equal to that produced by the diffused reflection from the pavements, fences etc. The candle-power directed to regions near the source should be limited to avoid "pools" of light due to excessive illumination.
The most satisfactory installations already in operation before the war were those in which the lanterns emitted a wide lateral beam spread, with little or no objectionable glare, and where the pavements were of light-coloured granite, bordered with white fencing or light stone buildings.
The trend of street lighting development appears to have inclined too much towards indicating the direction and limits of the motorist's track rather than towards revealing the presence of objects of persons on or near the track.
Lighting: Distribution, Lighting: Future, Lighting: Theory

New Members Elected To The A.P.L.E. p53
List of new members elected on the 27th August 1943.
APLE: Organisation

Adverts: The General Electric Co., Ltd, The Association Of Metal Sprayers, British, Foreign And Colonial Automatic Light Controlling Co., Ltd., Siemens Electric Lamps And Supplies Ltd., Metropolitan Vickers Electrical Co. Ltd, Engineering And Lighting Equipment Co. Ltd., Automatic Telephone And Electrical Co., Ltd. William Sugg And Co., Ltd., Concrete Utilities Co., Ltd., W Parkinson And Co., Philips Lamps Ltd., Walter Slingsby and Co., Ltd., Holophane Ltd., The British Thomson-Houston Co. Ltd., A. Bell & Co. Ltd., The Horstmann Gear Co., Ltd., British Electrical Development Association, Inc, Hobbs. Offen And Co. Ltd., Venner Time Switches Ltd., C. H. Kempton and Co., Ltd., Foster And Pullen Ltd. and Poles Ltd.