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ilp archive : journals

public lighting no. 43 vol. 11
October-December 1946

Editorial p127
Keep The Lights On p127
To save coal should be the aim of all. There are ways of conserving coal supplies without stinting the vital needs of essential public services. The requests made in recent months by regional fuel overseers, for lighting committees to cut down lighting by a defined percentage - which vary from place to place - is not only unreasonable but borders upon real danger. To cut down street lighting means one of two evils: either turn off entirely or reduce the amount of light. Each is bad practice. Modern street lighting, planned on scientific lines, cannot be tampered with by dispensing with odd lamps here and there. To do so is to increase the risk of street accidents. The same is to be said in instances of reducing light values. If reduced street lighting is the cause of one fatal accident, it is the right and duty of the public to make protest. It may cost the community, a further hardship to go short of a full quota of coal, but if by that small sacrifice a reserve of coal can be supplied for providing full street lighting and saving a life then it is worth it.
Lighting: Energy

Motorists - Take Note! p127
It is unfortunate that police is not taken in cautioning motorists who leave their cars facing oncoming traffic. It is an offence to existing regulations. And it spoils the good effects of street lighting. To be "blinded" by lights from a car standing at the kerb can quite easily cause an accident.
Lighting: Safety

A.P.L.E. Members, Note! p127
A London borough recently advertised for a "Mains Engineer and Public Lighting Superintendent". Representatives were made by the A.P.L.E. and Electrical Power Engineers' Association, each pointing out the undesirability of such an appointment - each case requiring the knowledge and experience of a separate and qualified Engineer.
Lighting: Management

Correspondence: Comments on the Conference by Francis F. Middleton p128
The conference at Cheltenham [1936] was the first opportunity that many authorities had obtained for making comparison between the then two new types of electric discharge lighting, although several lighting engineers had put fine installations of Sodium discharge lamps into operation prior to that date. I question the claim that sodium lighting has been brought into practice with the least possible delay - mercury lamps have been much more favourably exploited.
When properly applied, Sodium light is the most effective and economical system that has yet been installed for the provision of adequate visibility on heavy traffic routes. This is because:
  • At the low illumination values of street lighting, sodium has a shift in the visual response - dark tones appear in the field of view darker than they actually are, while the light tones appear lighter, so the contrast of objects again their background is more pornounced than with other types of lighting.
  • The lamps operate horizontally with a linear source, the light output being much more favourable to control for the production of a wide field of uniform brightness.
  • If visual acuity of vital importance then monochromatic light will produce the sharpest possible definition.
  • The extraordinary distant visibility observable in my existing installations, with their records of accident free traffic, proves conclusively that it has no superior for trunk road lighting.
The pioneers of Sodium lighting have contended with a great deal of misguided prejudice. Yet steady and successful progress has been made.
Lighting: Colour, Lighting: Lamps

The Late George Hulbert Wilson 1901-1946 by Jack Waldram p128
Obituary of George Wilson of the GEC.
Lighting: Personnel

Motorists Lose Bollard Claims from The Sheffield Telegraph p128
Two drivers claimed damages hitting an unlit bollard. The judge deemed the bollard was lit, and even if it wasn't, the street lighting was sufficient for the obstruction to be seen. He considered the plaintiffs were driving too fast.
Lighting: Legal

A.P.L.E. Luncheon Thursday 12th September, p129
Rt. Hon. W. S. Morrison, K.C., M.P. introduced the new president Mr. Clinch and gave a brief summary of Clinch's career.

A Life Saving Profession
There were far more accidents than there should be. After the war blackout, the industry of public lighting was coming into its own again. It was suggested that the lighting engineer was responsible for safety on the roads, but this was not so. The constructional side, which was the duty of the surveyor, there was also the duty of the motorist and pedestrian.

Street Lighting - But no Light
In London, many years ago, there was a Decree that during the hours of darkness, citizens should hang lanterns outside their houses, but it did not say the lanterns should be lighted! The result was that the citizens of London, law abiding as always, did not light the lanterns and it was not until long afterwards that the Decree was altered so that the lanterns were not only hung out but had to be lighted.
The President stressed the need for not concentrating on the economic aspect of street lighting, the primary consideration being the safety of the streets. It should be borne in mind that the Association was formed for a particular purpose and they must be objective in their desires and achievements. That purpose was the efficient lighting of the roads in this country.
APLE: Conference, Lighting: History, Lighting: Safety

Extinguishing Lights for 50 Years by P. V. Greensmith, Assoc., A.P.L.E., p130
It was about 50 years ago when the idea of a 'Mechanical Lamplighter', or 'Extinguisher', was causing Mr. John Gunning, many a night's lost of rest - for it was then that he patented and brought out his first Controller. The introduction of this 'Snuffer' was not easy going for, with the exception of a few gas engineers of the day, it was not generally appreciated that the new Controller would eventually be the Pioneer of Public Lighting Control. A company was formed to produce this extinguisher and this, coupled with the Incandescent Mantle, gave public lighting a major place in the everyday life of a community.
This early type did not do away with Lamplighters, because they still had to make the nightly trip to light up. His duty then included the winding of the mechanism by pulling a short chain with this torch pole, this action turned on the gas which was ignited by the tour. The clockwork was made to turn a dial to which a finger was attached at a predetermined position, so that after the clock had run for a given period, this finger struck the gas tap, and turned it off. Although this Controller did not cut-out the cost of Lamplighters, it did ensure the gas beign turned off at a fixed time, and the saving in this respect alone soon proved its commercial advantages for general use. From the date of its inception, imrpovemetns in the controller developed to meet the requirements of both lighting and extinguishing. Also the earliest type controller was made for use before the Mantle was introduced and the open type gas flame burner was the one means of using gas.
Lighting: Control, Lighting: History

Business Notes: Extensions Of Patents On Street Lighting Refractors p130
Mr. Justice Vaisey granted an application by Holophane Limited for the extension of the life of two patents covering dome refractors for street lighting periods for a period of five years. The two patents (Nos. 337398 and 398419) were taken on in the names of Holophane Limited and Dr. S. English and referred to Single-piece and Two-piece dome refractors. The original patents were taken out on 29th July 1940.
Lighting: Legal

Conference Handbook p130
Limited copies available and can be ordered.
APLE: Conference

Street Lighting From The Motorist's Point Of View by Mr. Edward Fryer, M.Inst.T., F.I.A.A. (Automobile Association) p131
Reproduction of the paper Street Lighting From The Motorist's Point Of View.

H. Midgley (Liverpool): Street lighting should be designed very largely from the point of view of drivers of motor vehicles, so they could drive in comfort and confidence, and so the safety of pedestrians was assured at night. Street lighting in unbuilt areas in rural districts was undesirable - it would be much safer not to have any street lighting. A great deal of the safety of roads depends upon the road surface, and everything should be done to persuade the road authorities to put down suitable surfaces.
G. L. Minchin (Manchester): Photographs should've been taken from the driver's point-of-view. Consideration should also be given to the position of traffic signs. The most important point of all was pavement illumination. It should be possible for the motorist to see a pedestrian stepping off the pavement; more thought should be given to the question of background lighting.
S. J. Scudamore (Gloucester): Agreed with different forms of lighting for different routes. In Gloucester they used mercury discharge lighting for through routes and sodium discharge lighting for circumrefential routes. Roundabouts and junctions were also lit with mercury discharge lamps. If this system was used nationally then it would serve a very useful purpose.
W. D. Reid (Aberdeen): As regards the system used in Glouecester, it might add to safety generally if the left-hand side of such roads were lighted with a different colour from the right-hand side.
H. S. Allpress (Simplex): The lighting of long traffic roads outside towns i.e. arterial routes, was not something very far away in the future. It had been done on certain sections on the Continent, and there was a famous stretch in Holland. Further, the lighting of intersections should use cut-off fittings.
Lighting: Authority Organisation, Lighting: Colour, Lighting: Safety, Lighting: Specifications, Lighting: Theory, Lighting: Users

The Quality of Public Lighting Installations and the Modern use of the Gas Source by Mr. Crawford Sugg, B.Sc.(Eng.), A.C.G.I. p135
Reproduction of the paper Street Lighting From The Motorist's Point Of View.

Dr. J. W. T. Walsh (National Physical Laboratory): Specially grateful to the author because he emphasised and drew attention to the fact that lumen output from street lighting lanterns was only one factor contributing to the quality of a street lighting installation. He was with the author 100% on colour: he strongly objected to being asked by his friends what had happened to him and to people going about looking like animated corpses. It was from an aesthetic point of view that he felt the colour of lighting was very important. He did not think the flash frequency produced any sort of fatigue on the eye at all.
Dr. S. English (Holophane): The problem with lighting at the horizontal appeared to have developed into a private war between gas and electricity. He did not know why because it was a fundamental matter in street lighting.
Mr. A. V. Horsfall (Gas Light and Coke Company: Was interested in the commercial side of street lighting and was interested in the new designs of lantern shown by the author because the cost or repairs and maintenance was an important matter. It was here the money went and they were all affected as ratepayers. The modern designs of gas lanterns reflected a great deal of courage on the part of manufacturers who had approached the problem from a new angle. For instance, with the old types of lanterns the glassware was fixed, and if glass broke, it ws necessary to remove the broken piece and put putty in a new sheet. That did not apply now. In the new lanterns, a new panel of glass could be put into position in a few minutes, and that was the end of the job. Further, the glasses had been standardised. Glass could now be cleaned in-situ. It was now not necessary to regulate burners in-situ. The use of light alloy metals obviated rusting and made the lanterns practically indestructible.
A. Greenaway Brown (G.E.C.): Mr. Sugg's suggestion that it is difficult for a lantern designer to avoid glare when the brightness of the bare lamp source is high is a provocative suggestion. Mercury vapour discharge lamps are not monochromatic and the newer types produce an excellent imitation of daylight colour. Considering Mr Sugg's suggestion that all light emitted from a street lighting lantern above the horizontal is wasted light some qualification is required. In open country, it is probably true that light emitted above the horizontal is wasted. But where there are buildings and trees then it serves a very useful purpose: (1) It makes the night appearance similar to the day appearance; (2) Assists the police in their detection of crime and (3) generally adds to the natural appearance. It is unfortunate that the draft British Standard Specification for street lighting should draw attention to the precise quantity of light emitted above the horizontal - surely this is not a main criterion and could be left to the discretion of the lighting authority.
Mr. J. A. Prowse (B.E.D.A.): The author had greaet courage in presenting so provocative a paper on such a contraversial subject. The references to the draft British Standard Specification laid emphasis on its treatment of the imponderable aspects of street lighting, and in this the author revealed the essential weakness of the specification, which might well vitiate its use in practice. In his view, the M.O.T. Report should be a Code of Practice backed by a consultant. The author had skated on thin ice in regards to brightness, glare and colour. He hoped that many of the physicists present would take up the author's reference to pulsating light. Dr. Walsh had confirmed that the eye solved the problem to our complete satisfaction at all road speeds and normal angles of vision. The eye did it with discharge lighting even better than it did at the cinema. The universal use of electricity for domestic lighting was due not to casual popularity but the ability to obtain the goods in a small, convenient package and at a better price. The same applied to the time lag in similar street lighting development now being so rapidly overtaken. It was due to the long-term nature of street lighting agreements and to the "sitting tenant" aspect of the remaining gas installations - and sitting tenants faded away, although not always quietly. The alacrity with which the gas fitting industry responded to the stimulus of competition was worthy of that great industry, but it was vitiated by circumstances over which it had no control - the cost of gas and the cost of electricity. The fact remained that where comparable street lighting was concerned, the gas lumen almost invariable cost more in raw fuel than did its electrical counterpart. The capitalised value of the saving by electricifcation was sufficient to finance the change over and show an over-all economy to boot. In Manchester, where the complete electricification and improvement of street lighting from one-third electricity and two-thirds gas, was going to save £30,000 and 30,000 tons over coal annually. He felt that Mr. Sugg's abilities were at present misapplied, and that when Sugg decided to make electric lanterns, they would hold the same respect from his electrical colleagues and competitors as his present products did from his gas friends.
Dr. Hopkinson (G.E.C.): Just before the war, he was responsible for some investigations into discomfort glare from street lighting installations. This was reported to the Illumination Engineering Society and a fairly simple method for evaluating discomfort glare was evolved. The author's figures giving the brightness of the individual sources of light, tending to give a distorted picture of what came out of the lantern. The glare from the flashed area of a properly designed lantern using electric discharge lamps was no higher than that from a lantern using high presure gas. The effect of colour distortion for a driver, in the case of mercury discharge lamps, only came into serious play at very high brightnesses and lighting authorities had never sanctioned the expenditure of sufficient money to bring street lighting installations into that category. It had little or no effect on visibility. With pulsating light, the pulsations were not of any great significance, but the optic nerve did not transmit to the brain that impression of a continuous source of light. The impulses along the optic nerve were pulsating and whatever the source, these pulsations always existed.
Mr. W. J. G. Davey: The principles of lantern design should take account of the following: The upper hemispherical light should be utilised by redirection on the road surface, there should always be a forward movement of the light across the road, a certain amount of spilt backward light was essential to illuminate the near pavements or buildings (because it was against these that a pedestrian was silhouetted), the shadowless redirection of light was also of value and if mantle reflectors were used their size should be a minimum because of the shadow they threw, and any reflecting devices should form the integral part of the lantern in order that they should not appear as after-throughts or gadgets that had been added later.
Mr. E. Stroud (B.L.E.E.C.O.): He did not think the street lighting problem was intricate as long as there was enough light. But he did not mean excessive light. The whole problem of safety on the streets was a question of having sufficient light. Colour, from the point of view of the motorist, was relatively unimportant. Visibility was the great thing and by spending more money on street lighting and using monochromatic light, the desired visibility could be obtained. It was better to look dead than be dead.
L. T. Minchin: Mr. Sugg overstresses the effect of pupil aperture when discussing light and dark adaptation and glare. The major difference between day vision and night vision lies in the retina. The changes which occur there enable the eye to accommodate a far bigger difference in brightness than could possibly be due to the comparatively small differences in area of pupil. Light which is only radiated to the stars is no more use to the purchaser than is a counterfeit coin.
R. W. Steel (Cheltenham): Despite its drawbacks from the aesthetic point of view, mercury and sodium lighting is steadily gaining ground. This emphasises that it is visibility which is the important factor and mono-chromatic light has more advantages in this respect than disadvantages.
H. S. Allpress (Simplex Electric Company Ltd): The draft specification is under reconsideration so it perhaps wise not to comment further. Unfortunately Mr. Sugg appears to place a special consideration on this clause with respect to the gas industry. This does not operate solely against the design of gas lanterns. It may be argued that the case is made more difficult for the electrical designer who is dealing with lamps giving a spherical light distribution. Therefore it would appear that the electrical industry is being penalised for the emission of light above the horizontal. The statement that glare will be reduced by increasing the radiating area of lanterns does not appear to be sound (unless dealing with 5-ft. fluorescent electric lamps). It is generally accepted that glare is independent of surface brightness over the small angles usually subtended by the eye by normal street lighting apparatus. Also, for "pulsating light" some proof would be of great value, and the stroboscopic effect effect does not seem to occur in movements along a street.
The Author: Would have to have a few words in writing with Dr. Walsh on the question of upper and lower hemisphere lighting, because he still felt there was an explanation and that ratepayers' money was being spent where it should not be. The term "distraction" for glare was used with malice afore-thought, because there's something in this problem which is not yet understood. The matter may be psychological rather than physical but it none the less real. The recent demonstration in Bond Street, London of fluoescent lighting with really large low-brightness sources goes some way to emphasise this point. Dr. Cotton stated in a recent publication that with 50-cycle operation of discharge tubes, the stroboscopic effect will be "very considerable" and even on a 500-cycle supply the effect would be detectable - although at this frequency its effect on vision would be almost negligible. In the main, gas sources have a flux predominantly in the lower heisphere, which is an inherent advantage. The present Draft Sepcification does not allow any credit to be claimed for this advantage.
Lighting: Colour, Lighting: Comparisons, Lighting: Control, Lighting: Distribution, Lighting: Levels, Lighting: Luminaires, Lighting: Materials, Lighting: Specifications, Lighting: Theory

A New Method Of Roundabout Lighting by A. Greenaway Brown, A.C.G.I., F.I.E.S. p150
This is receiving the attention of public lighting engineers in many places and is referred to in the Draft British Standard Specification for Street Lighting. An interesting experiment has been conducted by the Engineer of the City of Nottingham R. M. Finch, O.B.E., M.I.C.E. and Lighting Engineer to the City of Nottingham E. Howard, F.I.E.S. in collaboration with the Research Laboratories of the General Electric Co. Ltd.. The roundabout island is surrounded with a self-illuminated glass wall.
To render a roundabout reasonably safe for road users and motor vehicles in particular, it is suggested there are three requirements: (1) A warning; (2) A conspicuous shape and (3) background brightness. The Nottingham scheme meets all these requirements.
The wall acts as a warning sign because, seen from a distance, it can be easily recognised. It has a conspicuous shape as it is important the motorist can see the shape of the island before steering around it. The vertical black strips on the wall are uniformly spaced so that, in perspective, they appear more closely spaced to the left and to the right, thus indicate a curved obstruction. Considering the background brightness, any object passing in front of it will be conspicuous because it is seen in silhouette.
The wall is 3'6" high and stands 18" behind the kerb. It is constructed like a brick or stone house with windows on the front, the windows being illuminated at night by a white reflector and small electric lamps concealed inside. They are glazed with armour plate glass and to facilitate cleaning and lamp replacement the windows are hinged along the top edge so can be opened outwards.
It also dispenses the need for tall columns supporting lanterns for night illumination. The Draft Specification states "care must be taken to avoid a confusing array of lights which may mislead the approaching driver."
The capital cost is a little less than £6 per foot and the maintenance cost no more than for the conventional method of lighting with tall columns and lanterns.
Lighting: Installations, Lighting: Maintenance, Lighting: Theory

Experimental Applications of Tubular Fluorescent Lamps to Street Lighting by Mr. L. J. Davies, M.A., B.Sc. and W. D. Sinclair, A.M.I.E.E p151
Reproduction of the paper Experimental Applications of Tubular Fluorescent Lamps to Street Lighting.

Mr. Thomas Wilkie (Vice-President, Leicester): The authors had made a considerable contribution to the science of public lighting engineering. Fluorescent tubes were bracketed with other ideas such as captive balloons, kerb lighting etc., and had been classed with such improbabilities. He hoped that every delegate had seen the Bond Street installation. His immediate reaction in Rugby was that the light was not only good but rather too good. In Rugby a very narrow street was selected and central suspension was adopted. He viewed it on a wet night, and there was a large central streak, but it was not objectionable and the kerbs were reasonably well lit.
(1) The usefulness would apepar to be limited to shoping centres where the colour of discharge lamps might be considered objectionable.
(2) The capital cost is bound to be such as would militate against their general adoption, but even the saving of energy would only apply when compared against tungsten or gas lighting.
(3) The weight of the lantern brought in its erectional problems which did not arise normally and would mean still further costs for sturdier poles or duplicate span wires.
(4) Owing to the size of the fitting, the mounting height could not, be less than 25 ft.
(5) Further practical and uncontrolled tests would appear to be very necessary on the question of cold weather behaviour.
(6) Maintenance in situ would certainly require at least two men and a different type of tower ladder.
(7) The 80 ft. spacing could be extended quite a lot - possible even to 120 ft. and would still give good results.
There were many points in favour of this system as far as the electrical and mechanical arrangement were concerned.
(1) The lantern cut-off was very happy and the buildings received sufficient light to make the whole street alive. He could discern absolutely no glare.
(2) Small current consumption.
(3) Arrangement where one tube could be used (for midnight switching) was most effective.
(4) Long life of tubes. Each tube would give almost a year's service.
(5) A lamp failure would not be very serious - certainly not for a night or two.
The authors should get a few more installations going under practical working conditions, and collect data which at the moment was bound to be lacking.
Councillor Selwood (Swindon): As near it was possible to copy daylight in street lighting, the better for humanity it would be.
Mr. J. F. Colquhoun (Sheffield) (Swindon):After viewing the Bond Street installation he was thrilled; Mr. Davies and his colleagues had solved many of the problems of the public lighting engineer: (1) There was no glare; (2) The spread of light was admirable - bearing in mind that Bond Street was narrow with high buildings on either side. The fact that the street was narrow enabled span wires to be used, and that might not apply in other places, but for small-town streets this was more than a little improvement on what existed at the present time. It represented a fundamental change in outlook. Not long ago he told a friend that fluorescent lighting for street work was an impossibility; he thought the units were too large and could never be handled. He hoped that BTH and others who might be engaged on this kind of work would be get full support of the lighting authorities of the country, without too close a regard to the £. s. d. in experimental work of this nature. Local authorities were far too mean in this connection. The public wanted efficient lighting and were perfectly willing to pay for it.
Mr. J. G. Christopher (G.E.C.): The application of fluorescent tubes for street lighting should be treated on merits and the lamps should not be put to jobs for which they were not suitable. In addition to the three lanterns described, there was a bigger lantern capable of working with longer spacings, and those who visited the G.E.C. laboratories at Wembley would see a 7-lamp lantern for this purpose.
Mr. Leach (Central London Electricity Ltd.): It was specified there must be good colour lighting with no glare. It was felt that fluorescent lighting showed great promise, and his company was very fortunate in securing the prompt co-operation of two or three important manufacturers. It was hoped in October it would be possible to demonstrate other trials which would include the 7-lamp lantern. The Bond Street installation was put up in two weekends, and while it could be said to be a success, there were still a good many things to be learned. He was convinced that it would be possible, with this form of lighting, to cater not only for shopping centres but for other types of street also. The system was already showing a large number of advantages and on the economic side he had every confidence that the system would prove as cheap as any other form of lighting and with better light. It was too early yet to speak definitely of costs.
Mr. L. J. Minchin: The lighting of Bond Street was a step in the right direction. The Bond Street lighting formed a canopy of the road and it gave an extremely large source of low brilliancy. Could two shorter sources 5 ft. apart be used - like the Victoria Embankment and Blackfriars Road.
Mr. Sinclair: The lumen rating per 100 ft. of road was between 8000 and 9000 lumens. It would've been unwise to carry out the experiment under conditions which were not favourable, but the results of the experiments afforded an impetus for future work.
Lighting: Distribution, Lighting: Installations, Lighting: Lamps, Lighting: Levels, Lighting: Luminaires, Lighting: Specifications, Lighting: Theory

Centralised Remote Control Installed In Central London p159
A section of the network administered by the Central London Electricity Ltd has recently been equipped with Rythmatic Street Lighting Centralised Remote Control. It is located in the St. Martin's Lane sub-station and includes a control panel, equipment for generating audible frequency currents from 300 to 1000 cycles and injection apparatus for superimposing the A.F. currents in accurately timed impulses on to the network. Street lighting in the area bounded by the Mall, Whitehall, Strand, Trafalgar Square, Leicester Square, Charing Cross Roda and Northumberland Avenue is controlled by this installation, the 1,500W lamps being directly switched by "Rythmatic" Relays mounted on each lamp standard.
Lighting: Control, Lighting: Installations

Adverts: Poles Ltd, The Association Of Metal Sprayers, Stanton Ironworks Co., Ltd, Siemens Electric Lamps And Supplies Ltd., Automatic Telephone And Electrical Co., Ltd., Engineering And Lighting Equipment Co. Ltd., Holophane Ltd., Philips Lamps Ltd., British Gas Council, Crompton Parkinson Ltd., British Electrical Development Association, Inc, Stewarts And Lloyds Co., Ltd., The British Thomson-Houston Co. Ltd., E. K. Cole Ltd, Willey And Co. Ltd., The Horstmann Gear Co., Ltd., British, Foreign And Colonial Automatic Light Controlling Co., Ltd., Falk, Stadelmann Co., Ltd., Metropolitan Vickers Electrical Co. Ltd, Broad And Co. Ltd., Brighton Lighting and Electrical Engineering Co. Ltd, William Sugg And Co., Ltd., Hobbs, Offen And Co., Ltd., James Keith And Blackman Co., Ltd. Sangamo Weston Ltd. and The General Electric Co., Ltd.