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ilp archive : journals

public lighting no. 46 vol. 12
July-September 1947

The Annual Conference p47
Annual General Meeting
Mr. W. N. C. Clinch, the retiring President, was in the Chair for the AGM. Messages were sent to the King and the National Technical Conference of America. The accounts were then presented and approved. The following elections were announced: Mr. Thomas Wilkie (Leicester) as President and Mr. N. Boydell (Eastbourne) as Vice-President.

Official Opening of Conference
The Mayor officially opened the Conference. The displays of street lighting showed how far we'd advanced since the days of the flat-flame gas burner. In those days that form of lighting was regarded as wonderful but times had changed since then. The outgoing President replied that it was necessary to bear in mind that there were special difficulties at the present time, and that it was impossible to do as much in street lighting as those responsible for it would like. Nevertheless, why should they not pave the way for the morrow, when it was hoped that conditions would be very much better? That was the real aim of the Conference.
Both C. I. Winstone and E. J. Stewart wished to retire from the Council and were both made Honorary Members.
Five papers were received in July for the papers competition and these would have to be considered before a conclusion could be arrived at.

Induction of New President
Mr. Thomas Wilkie was made President, who'd been President in 1930. A great deal had been done in the last year including a deputation to the Ministry of Transport. Moreover the officers of the Ministry of Transport consulted the Council of the Association on all matters appertaining to street lighting. Wilkie believed that lighting engineers should have proper qualifications so that, having started in the profession, he would be in the position by subsequent experience to reach the highest posts. The interest in public lighting was very widespread and very real. It must be the view of all of them that when one person was killed as the result of defective lighting, nothing could be done to bring them back to life again. Therefore, the members of the Association must regard themselves as a team and apply their minds to the many problems involved in street lighting in order to make the roads of the country as safe as possible to all who used them. During the war we had to pass through trying times, as far as street lighting was concerned and it must be remembered that there was this perculiar psychological reaction at the present time. They were short of coal, which was unquestionably the thing we desired for the purpose of bartering with other countries who could supply us with our needs in return.
APLE: Conference

Public Works Congress p49
In connection with the Public Works Congress held in July at Olympia, a special session was held under the auspices of The Association of Public Lighting Engineers when Mr. N. Boydell, M.I.E.E., Borough Electrical Engineer of Eastbourne, presented The Development And Trend Of Street Lighting By Electricity before a very large audience. The Council of the Association considered the paper of sufficient interest to have it reprinted and a copy circulated to each member.
APLE: Journal, Lighting: Installations

Street Lighting in relation to Road Safety, Traffic Problems and Crime Prevention by A. E. Marchant, M.Sc.Tech., M.I.E.E., A.M.I.Mech.E and Robert Bell, Assoc.M.C.T., M.I.E.E., A.M.I.Mech.E p51
Reproduction of the paper Street Lighting in relation to Road Safety, Traffic Problems and Crime Prevention.

Alderman F. Thraves (Sheffield): Those who had taken an interest in road safety from those early days has been looked upon as a body of interfering people who had nothing else to do, but now it had received such recognition from the Government, and the problem had become so serious, that it was exercisign the minds of everybody. He thought the authors had not laid sufficient stress on the fact that the motorist had two powerful headlights which helped him considerably in his difficulties in the darkness. It had often been said that it was better to have complete darkness than intermittent darkness and he would not have been surprised if someone said there should be no street lights at all.
Mr. E. C. Lennox (Newcastle-on-Tyne): The lack of street lighting was bound up with lack of coal production. It resulted in street accidents to individuals and damage to motor vehicles and other property. As a result there was the necessity for hospital treatment, reduced man power and a waste of national resources. As a result there was the necessity for hospital treatment, reduced man power and a waste of national resources. When all these factors were taken into account, it was a question of how much coal was really being saved in the decision to cut down street lighting. Less street lighting meant less use of the streets by the public in going about their normal duties and to places of entertainment, and this must mean a greater use of fuel in the home. Again how much fuel would be saved in this way and how it did compare with the small saving in coal renderd possible by reducing public lighting by 50 per cent. We were wasting more coal in reducing street lighting when all the implications were taken into account.
Mr. W. Bicknell (Siemens): A committe had just been appointed by the Road Research Bord on a proposal emanating from the British Standards Institution. The terms of reference were "To consider the general question of street lighting in relation to road accidents and to make recommendations as to the best method of securing adequate lighting for the needs of vehicular and pedestrian traffic." The chairman was Sir Clifford Paterson.
Mr. S. J. Chamberlain (Assistant Secretary, Traffic Department, New Scotland Yard): For a point point of view, street lighting was not just an amenity or a desirable thing but an essential both from the point of view of traffic and of crime. But what we should avoid in street lighting was persistent light and dark patches which were found even in what were considered well designed schemes. It was clear that a very high proportion of night accidents were due to bad street lighting and patchy street lighting. Scotland Yard held the view that if street lighting was reduced the number of night accidents would increase and that proved to be the case.
Mr C. C. Goodman (Chief Constable, Halifax): The majority of night accidents were due to bad street lighting. He advocated schemes which did not permit of patchy lighting and hoped to see the day when all main traffic routes whould be lighted in a clear and shadowless manner. Everything must be done to avoid the dangers which arose when drivers passed from well lighted to badly lighted areas. The Lighting Superintendent of Halifax always consulted him in connection with new lighting schemes and they examined bad accident spots together at night and endeavoured to do everything to minimise the danger. It was no good saying we could manage with reduced street lighting; we could not.
Mr. F. W. Axford (Northmet Co.): The problem was the lack of statistics to enable it to be brought home to the responsible authorities. One important factor in this respect was the night/day fatality rate. The Royal Society for the Prevention of Accidents was now giving figures for the country as a whole but he had not yet been able to trace what the effect street lighting had on these figures. The United States had carried out considerable research into accidents. He suggested that local authorities contemplating installing new lighting schemes should consult with the police and keep records for 12 months before installating and 12 months after installing improved lighting.
Councillor W. Hebden (Shoreditch): He did not think prevention of crime was a major responsibility of the public lighting engineer. An examination of the records showed that the greatest number of "jobs" were carried out in the best lighted street because the loot was there. Also from the point of view of street accidents, the best lighted thoroughfares in his district were the "black" spots because there was the largest amount of traffic there and the greatest number of people were passing.
Mr. L. T. Minchin: It is very difficult to get real solid statistics to show anything very definite. Where beacon lighting was adopted, it should be specially treated and designed. (One scheme which caused an accident had lamps every 200 yards on short posts on one side of the road). There should be some form of semi-cut off fitting adopted and one that did not glare on short posts.
Councillor D. Harvey (Waltham Holy Cross): He complained that in his district the streets were very narrow - only about 20ft. wide - and yet the Ministry was constantly pressing the local authority to do away with more and more lamps. With full street lighting, the accident rate in his district, was very low and he was one of those who believed that the small amount of coal saved by a reduction in street lighting was more than offset by other factors.
Mr. E. E. Jolly (Borough Electrical Engineer and Manager, Bethnal Green: The authors suggested that half lighting is better than none. They also appear to suggest that this half lighting will be a means of saving life by preventing accidents on the roads. However, the amount of improved lighting i.e. 50% pre-war for 1946, does not appear to indicate that the half lighting scheme is better than the 0.02 ft. candle lighting of 1945; the death rate is greater apparently with half lighting. It is suggested that this is due to the fact that a greater number of vehicles are now on the roads, which may be true, but may also be due to the band arrangements with half lightign. With the 0.02 ft. candle lighting we had uniform lighting which was generally bad, whereas with the half lighting many authorities (both gas and electricity) have staggered their lighting fittings i.e. had only alternative fittings in lighting with the result that there is a considerable amount of shadow which has made the roads extremely dangerous. To meet the 50% reduction, authorities should light main roads fully, the reduction made on side streets, where motorists should use one or two headlamps. It will be agreed that approaching a roundabout in darkness is extremely difficult and dangerous. If sodium lighting were installed at just roundabouts and main road junctions then it would be an indication to all vehicles to extinguish headlamps and proceed with caution. The authority which I represent has for one or two winters used sodium flood lights at heavy road junctions for fog purposes, and although for fog purposes yellow lighting is a fallacy, I am quite convinced that it has been the means of assisting and very definitely acts as a warning to motorists that caution is necessary.
Mr. Marchant (Reply): The figures showed what a small amoutn of coal was used for public lighting and the authors personally felt that fuel used for public lighting was not wasted. They would rather see that fuel used to prevent accidents than to see it used in our hospitals and mortuaries. It had been very interesting to hear the police point of view. It was useful to know that Scotland Yard confirmed the views expressed in the paper with regard to patchy lighting. It was true that the best lighted spots were often the "blackest" from the point of view of accidents but the best lighting should be put where the traffic was most dense. Beacon lighting was bad for motorists but could be some assistance to pedestrians. For main road lighting beacon lighting should be avoided. The great need was for more statistics.
Lighting: Anti-Social Behaviour, Lighting: ARP, Lighting: Energy, Lighting: History, Lighting: Health, Lighting: Levels, Lighting: Safety, Lighting: Statistics, Lighting: Users, Statistics: Accident Data, Statistics: Road Data

The Holophane Photo-Electric Street Lighting Photometer p60
The new British Standards Street Lighting Specification [since dropped] makes it necessary to measure the vertical illumination at certain test stations. These illumination values are required to measure the acceptance figure. Ordinary Light Meters are insufficiently adaptable or accurate at the low illumination levels provided in streets to provide reliable data.
It has four evenly divided scale ranges, the lowest range having a full scale deflection of 0.15 foot-candles, allowing direct readings to an accuracy of 0.002 foot-candles. A second control switch provides automatic correction for different types of steret lighting illuminants enabling direct readings for installations of incandescent gas, tungsten filament lamps and mercury and sodium discharge lamps.
A zero setting adjustment is provided, together with a built-in spirit level, and the illuminated scale and control panel enable easy manipulation and accurate observation of the scale readings in dark situations.
The light sensitive cell is connected to a flexible lead so that the operator can stand behind or at a suitable distance from the test position, thus avoiding obstructing shadows.
Candle-power values can be calculated by placing th test surface with carrier and tripod at a known distance from the light source and adjustign the cell to such a position that the rays are intercepted along the normal to its surface. Then use the inverse-square law to calculate the candle-power from the foot-candle reading. It is essential to shield the cell surface from extraneous light and other sources and a stray light shield is available for this purpose. This accessory is a rectangular matt black enclosure divided into two compartments by a longitudinal partition: one accommodates the photo-electric cell at one end and has a diaphram of suitable size; the other compartment includes a direct view-finder, which enables the operator to train the test cell accurately normal to the source.
Lighting: Equipment

Maintenance Of Public Street Lighting by J. Woodhouse (Lighting Dept., Sheffield) p61
Reproduction of the paper Maintenance Of Public Street Lighting.

Mr. A. G. Tookey (Bristol): In Bristol, the lamp attendant did not fill in as many forms - this should be done by the inspector. In Bristol there was a district foreman to 4000 lamps, and he knew every lamp and his attendants. He did not like the idea of the 'mystery' inspector who had a weekly tour trying to find some fault.
Mr. R. S. Bradley (Portsmouth): There was a lack of information on this subject, especially with regard to costs. Lennox had shown that the three main items of annual expenditure: energy, capital and maintenance - the latter represented 25-50%. Therefore maintenance costs had to be kept low. The paper contained useful information but there wasn't enough of it: what of the fittings and poles; how were they maintained; and to what standard and at what cost? He agreed with the necessity for regular nightly inspections because this kept a watch on the failures but served as a check on the condition of the equipment. All accidents were not reported and there appeared always to be a small section of the public which could not resist the temptation to interfere with public property. No mention was made of electric controllers. The method of using spare refractors had several disadvantages e.g. more extra handling with more chance of breakages, and glassware was scarce. Where special pattern refractors requiring careful fitting were concerned, he did not think it desirable to disturb them. What was the author's average costs of cleaning, and what was the average number of units dealt with by a tower wagon per day?
Mr. R. L. Greaves (St. Helens): There were other factors he wold like to have known about. One was the enormous breakage of glass, particularly on the gas side. In St. Helens armour-plated glass had been used in some of the side streets. As a gas engineer he was intrigued by the reduction of gas pressure - all gas lamps he knew were fitted with governors to maintain the gas pressure at 2 in.
Mr. J. Howard Long: Practicable lighting equipment should be completely dustproof, and the glass or other transparent surface should be so disposed that it did not collect dust falling by gravity
Mr. R. Parker (Aberdeen): There was not sufficient detail in the paper. For instance, the author dealt in particular with only one type of refractor fitting i.e. the open, single-piece type which was open to the air and the accumulation of dust. The problem of dirt was not a new one and the fitting manufacturers were not unaware of it. There was the two-piece refractor with sealed in prisms, and there was the non-ventilated refractor which was sealed to the extent that dirt did not accumulate on the prisms. There was a method of testing the dirt accumulation on single piece refractors on the assumption that the degree of dirt accumulation was directly related to the degree of loss of visibility on the street. He did not know whether that was the case. Did the accumulation of dirt effect the vertical or horizontal redirection by the prisms? Could the author give relative costs of maintaining the different types of fittings.
The President: The author mentioned that lamps were cleaned once a fortnight but this was too long and interval and in Leicester the lamps were cleaned once a week. The filling in of forms by the attendant was overdone.
Mr. W. Hine (Yorkshire Elecrtical Power Co): Their problems of maintenance of street lighting installations were very different than the author. His area was 3000 square miles and included a large number of local authorities for whose lighting installations he was responsible. The Sheffield model was uneconomic in his case, particularly for small villages. This confirmed what Mr. Lennox said in his I.E.E. paper concerning the wide divergence in the cost of maintenance of street lighting in various areas.
Mr. L. A. Doxey (Leeds): He has similar problems to those of the author, his town being of similar size. He cleaned in some parts of the City every week and in others every 16 or 17 days. He would like the manufacturers, when they introduced a new fitting, to assemble 30 of them on a wet day from the top of a tower wagon. He also hoped the manufacturers would turn out a dustproof fitting as he had not found one yet.
Mr. C. C. Smith (Liverpool): He has similar problems to those of the author and dealt with them in a similar manner. The filling in of forms had to be carefully watched because maintenance men were neither qualified or able to fill in forms. In Liverpool each area was divided into a number of smaller areas each of which were in charge of a lamp attendant foreman who had 8 or 9 attendants under him, each of whom had their own sections of 200 to 300 lamps depending on the type of control and the density of the area. There were three inspectors at headquarters who were mobile and they went out at night and made a completely impartial report on the condition of the installation. Refractors were not employed in Liverpool and they were not sure they were as efficient as claimed. On A and B roads in Liverpool, cut-off lanterns were used and the light was put where it was wanted. Such careful control wsa not so necessary in the side roads and there might be a more general distribution of the lighting. Maintenance problems were considerably simplified if refractors were not used. He agreed that the new type of refractor that exposed only smooth surfaces to the weather was a great improvement. He was trying out armour plate glass in Liverpool, but was afraid that juvenile offenders would accept this as a challenge and the final result might be damage to the whole lantern.
Mr. J. H. Morrison (Bolton): Heartily endorsed what was said as to the co-operation of manufacturers before introducing new types of fittings or new ideas for light distribution. Forms should only be filled in by a foreman who knew what was happening.
Mr. P. Richbell (Croydon Gas Co.): How many lamps were maintained by each attendent and whether their were any difficulty with nightly inspections, particularly at the weekends. This was one of the latest problems in the London area and he had overcome it in the following manner: The man now workd a normal 44-hour week. The nightly inspection was carried out by the district foremen who were responsible for a certain number of lamp attendants and supervised their work during the day time. These foremen were each provided with a motor van for the nightly inspection and thus it was possible to have an inspection by the men responsible for the particular aeras.
Mr. H. J. Risby (Gas Engineer, Southport): He found his men were expected to do mrore than was reasonable. They were expected to make a tour of their round in the morning and ensure the lamps were all out. Then they had to go round and carry out cleaning and maintenace. And in the evening they went round again to make sure all the lamps were alight. The system was not working very well. He therefore introduced a two-shift system by which one week the attendant made an inspection in the morning to make sure the lamps were out and then went round doing the cleaning and maintenance. The other shift did their round in the afternoon doing cleaning and maintenance and then went around in the evening to make sure the lamps were all alight. Men, who were not performing well, were told that if a beter job was not made of the street lighting, then the electrical people would get the street lighting and then they would lose their jobs - this had been found to be very effective. The lamps in Southport were well maintained although he admitted they were in a fortunate position in that they did not have the problem of an industrial atmosphere.
Mr. Woodhouse: Removal of refractors was quicker and more satisfactory than trying to clean the refractor in situ. If a lamp attendant was not capable of filling in a form then he should not be employed at all. The travelling inspectors were not "mystery" inspectors by it was a pre-arranged visit and it worked very well. Costs were not given in the paper as many of the items varied from place to place i.e. the cost of electricity and gas was rarely the same in two places and therefore it was difficult to compare costs. Armour plate glass had been used in Sheffield but it was expensive and it would need some investigation to ascertain how long this glass would last. The dust-proof lantern had been mentioned but he had not come across one yet. Two piece refractors had been used to a considerable extent before the war but when cleaning it was found that the interior was very dirty, suggesting that the dust had got through. The attendants in Sheffield were expected to look after 300 lamps, although the number varied with the type of lamp, type of fitting and type of controller. This included cleaning the lamps once per fortnight. Collaboration on the part of manufacturers had been raised at previous Conferences, and it was once suggested that a Committee should be formed with the manufacturers to look into the question of designing lanterns which were easier to handle than some which were available.
Lighting: Equipment, Lighting: Maintenance, Lighting: Management

A Useful Handbook for Lighting Engineers p69
Details of the Penmaenmawr Pocket Book which is intended for use in the field by all those concerned in the design, construction and maintenance of the highways. Special attention has been given to street lighting.
Lighting: Publications

Patent Progress by S. T. Madeley p70
Changes in patent legislation after the war.

The American Approach to Public Lighting (Part Two) by H. L. Juliusburger, F.I.E.S. p71
(Concluded from the previous issue)

The Potential Market.
What is the potential market? The electricity undertakings, more active now in thefield of Street Lighting, hope for an ultimate sale of 8,000,000,000 units p.a. San Francisco is quoted as an example where a 9-fold increase in consumption for Street Lighting of a main street has produced an 8-fold gain in shop lighting consumption. This raises a point of interest which is commented upon by the Canadians: the Toronto authorities state it is imperative to increase Street Lighting in shopping areas where the intensity of shop lighting is acutely distracting the vehicle driver from a clear observation of the road, and they call for a measure to blend one type of lighting into the other. If the San Francisco experience is to be taken as indicative of a general trend, this condition mught develop into a vicious spiral.
The manufacturers estimate an increase in numbers of lamp posts at 3,000,000 and the light output per point to go up to a minimum of 4000 lumens in roads with light traffic and 10,000 lumens in the case of heavy traffic. The present national average is 2500 lumens per light point. Some 1,500,000 "radial wave" reflectors designed 40 years ago are still in use and considered obsolete.

The so-called "Planned Street Lighting Programme", essentially a direct sales effort aiming to contact some 14,000 municipalities, promoted by the NEMA and supported by the utilities, suggests a 10-year lay-out for improvements, a period which is reiterated with great uniformity in all types of publications on the subject. Some municipalities, judging by the pace lighting developments have taken in the recent past, might be hesitant to decided on improvements now in the fear that today's decisions may be superseded by fresh technical developments in the course of the next ten years, it is repeatedly stated that no fundamental changes of present day street lighting technique can be expected in the near future. Recent experiments carried out to prove or disprove the value of fluorescent lamps in the field of street lighting have been arranged just now.
What is the reaction of the municipalities? In the bigger communities, thre names stand out as promoter of the casue: Detroit, Denver and Toronto.
Detroit: The Mecca of modern Street Lighting specialist.
Denver: The protagonist of Mercury Vapour Street Lighting. In 1945 some 1000 mercury lamps were in use at that time in that town and it is specially ephasised that the public is appreciative of their visibility value. Mercury lamps were used for reasons of economy when the administration was faced with the task to raise visibility in certain streets but there was not the sufficient funds. The lamp selected is the 400-watt type giving 16,000 lumen.
Toronto: Has embarked on a thorough test programme to establish the governing factors required to replan the lighting system of the whole town methodically The present lighting system had been designed in 1910 and all that had been done was to raise the mounting height of the lowest fixtures from 9 ft. to 12-17 ft. Eight different lanterns of various directive types are on test. Central and curbside suspension, double-pole and staggered formation are systematically explored in relation to the various road and traffic conditions in the town. Part of the experiment is to reduce the number of standards - spacings up to 400 ft. are mentioned - compensating by increasing the mounting height and light output per point. Toronto has 48,000 street lamps and the total expenditure is expected to be in th region of seven figures.

Remarks on Technical Aspects
Mounting Height: There is a marked tendency to go to a height of 30 ft. The effects of glare of any description can be considered negligible when the light source is near or above 30 ft. height.
Spacing: According to statistics published in 1935 the average spacing between street lamps in the country is 327 ft. linear length of road. Shifting light points is considered expensive so it's recommended to keep the spacing and to increase the mounting height and the wattage of the lamps.
Type of Light Source: 97% of light sources are tungsten filament lamps. Hopes are expressed that mercury lamps will be more widely adopted. Great efforts are made to encourage the use of sodium lamps but rather as a dual-purpose luminaire for lighting and warning. This is a marked difference to official recommendations made in this country. Applications of the sodium lamp is advocated for road juntions, traffic circles, bridges and tunnels.
Roadways Illumination Values: Official recommendations go down to minimum average values of .2 f.c. for certain conditions. It is pointed out that higher illumination values are desirable. It has been expressed that .8 f.c. is the minium value.
Fluorescent Lamps: Systematic experiements have been carried out to establish advantages and disadvantages of fluorescent lamps in street lighting. One advantage has been established: A linear light source will produce a more useful brightness pattern on the road than a point light source in wet weather. But a number of disadvantages have been established which restore the balance in favour of tungsten lamps, which are the low lumen output per ft. tube length and its size. Any fitting to house the lamp will be bulky and make the installation undesirably conspicuous in daylight; further the directional properties are poor due to the tubular shape of the light source; and jackets will be necessary in cold weather.

Lighting: Funding, Lighting: Lamps, Lighting: Levels, Lighting: Statistics, Statistics: Road Data

Adverts: The General Electric Co., Ltd, The Association Of Metal Sprayers, Stanton Ironworks Co., Ltd, Siemens Electric Lamps And Supplies Ltd., Automatic Telephone And Electrical Co., Ltd., Broad And Co. Ltd., British Gas Council, Brighton Lighting & Electrical Engineering Co., Ltd., Holophane Ltd., Stewarts And Lloyds Co., Ltd., REVO Electric Co., Ltd., British Electrical Development Association, Inc, The British Thomson-Houston Co. Ltd., Concrete Utilities Co., Ltd., Crompton Parkinson Ltd., Gowshall Ltd., J. W. & R. E. Hughes, A.P.L.E., Engineering And Lighting Equipment Co. Ltd., Walter Slingsby and Co., Ltd., Willey And Co. Ltd., British, Foreign And Colonial Automatic Light Controlling Co., Ltd., Falk, Stadelmann Co., Ltd., The Horstmann Gear Co., Ltd., The Gas Meter Co. Ltd., Metropolitan Vickers Electrical Co. Ltd, William Sugg And Co., Ltd., Hobbs, Offen And Co., Ltd., James Keith And Blackman Co., Ltd., Sangamo Weston Ltd. and Poles Ltd.