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ilp archive : journals

public lighting no. 14 vol. 4
July 1939

Editorial p35
The National Fitness Council have published a report on fitness in the UK. Floodlighting of open spaces during winter months is therefore required. The tests and investigations made by the Council appear to prove that the floodlighting of playgrounds, football fields and swimming pools is economic and practicable. Floodlit games are common abroad. Local authorities should consider grants from the National Fitness Council towards the capital cost of installation.
Progamme for the Congress at Glasgow has now been made public. "Still better lighting" appears to be the watchword of the Conference.
APLE: Conference, Lighting: Floodlighting

Uni-Directional Lighting p36
A new system of street lighting for double-carriageway roads has been installed on the Great Chertsey Road, Twickenham. It is the outcome of experiments by the GEC at Wembley. It reduces running costs by 60% without entailing any sacrifice in efficiency. Ordinary installations using 400W lamps can be carried out under the new method with 125W lamps; similarly 250W lamps can be replaced by 80W. This leads to a saving of 350 per mile. Research has shwon that light is required only in one direction - opposing the traffic flow - on each carriageway of a dual road. It gives improved revealing power by accentuating contrasts of obstacles on the roadway, and driving comfort is increased as the only light sources to be seen are on the driver's own carriageway. The Uniway lantern is the first lantern on the market for dual-carriageway roads. It is designed for Osira 80-125W mercury vapour lamps. The whole of the light is refelcted in one direction - towards oncoming traffic - and an extremely event "flash" is obtained as a result of special diffusing glass. The outside surface of the glass is smooth to facilitate cleaning. The "flash" covers an area of more than 100 sq. ins. whereas most ordinary 400W lanterns have a flashed area of only 60-80 sq. ins. Thus, surface brightness of the lantern per square inch is considerably reduced owing to its greater light emitting area. The lantern is in two parts - a detachable top which the brack arm slides horizontally, giving side-entry mounting, and the main lantern body. Both parts are made of light alloy castings and the complete unit weights on 15 lbs. The Uniway lantern is totally enclosed, non-ventilated and completely weatherproof. The front is hinged at one side and secured by simple postive action snap catches. Access to the lamp and reflector is afforded by the hinged front. The body can be rotated on the bracket arm so the light can be accurately directed towards the road. For thsi purpose an orthoptic sighting device is provided to enable the lantern to be correctly aligned. The lamp is automatically centred and is firmed held in the correct focal position. The lantern is simply erected, as the top, which weighs only 2lbs., can be slid on the bracket arm and there locked into position. The leads can be wired to the lampholder in a few moments and the body is connected by self-locking nuts.
Lighting: Distribution, Lighting: Installations, Lighting: Luminaires, Lighting: Theory

The Conference, 1939. p73
Details of the forthcoming conference in Glasgow
APLE: Conference

Glasgow Lighting Department p74
The department is one of the oldest services of the Glasgow Corporation. In 1800, the first Glasgow Police Act made the lighting of the streets a statutory duty. The streets were lit with oil and wick. In 1817 the first gas lamp was lit. In 1862 an Act Of Parliament was obtained to deal more effectively with the lighting of the city, and the lighting of courts and common stairs came directly under the Corporation. There are 36,650 lamps under public control in streets, lanes and courts: 16,072 gas and 20,578 electric. Owing to the number of tenements, there is an abundance of stair lamps. These "common stairs" are lit with 69,017 gas and 24,379 electric lamps. Thus the total number of lamps under public control is 130,046. The department continously experiments with new illuminants, fittings, materials and methods of control. There are 186 street-lighters and 599 attendants for stair lamps. The department's own workmen make, erect, fit and repair both gas and electric plant. There is a staff engaged on design and a well-equipped testing department carries out routine and experimental photometric and other tests. The erection of brackets on tramway standards and special steel lighting standards absorb the use of two motor cranes, nine motor tower-wagons and several hand-towers. In addition to public lighting, the department deals with street name tablets and number tablets, traffic direction and warning signs, some being illuminated by the department. It also undertakes at a charge, the provision and lighting of private roads. And has also erected and maintained 48 lamps on highways outside the city for local authorities. The lighting of clocks has also been under the charge of the department. It even cleans the windows of the Corporation buildings.
Lighting: Equipment, Lighting: Management

Demonstration Lighting p75
Details of the forthcoming exterior exhibitions in Glasgow
APLE: Conference

The Conference Sessions p75
Details of the forthcoming conference programme in Glasgow
APLE: Conference

Social Functions p75
Details of the Civic Reception and the Luncheon (with trips to inspect installations and substations).
APLE: Conference

For The Ladies p75
Details of the trip by motor coach to the Loch Lomond Park. (Gentlemen could go too!)
APLE: Conference

The Kyles Of Bute p76
Details of the trip on Thursday afternoon to the Kyles Of Bute. "Let Glasgow flourish!"
APLE: Conference

London County Council: Floodlighting Of Playgrounds In Parks And Open Spaces p76
Following successful experimental floodlighting of playground at Eelbrook Common in 1937-8 (see Public Lighting #12) the LCC have made similar installations at a further twelve sites. All the sites are equipped with Benjamin Duoflux reflectors mounted 24' on REVO Humberstone steel columns. The installations are:
  • Archbishop's Park, Lambeth: 9 columns; 250W mercury discharge lamps.
  • Highbury Fields, Islington: 24 columns; 12 1000W GLS and 12 500W GLS.
  • Kennington Park, Lambeth: 12 columns; 12 1000W GLS
  • King Edward Memorial Park, Stepney: 17 columns; 17 500W GLS
  • Meath Gardens, Bethnal Green: 17 columns; 17 1000W GLS
  • Tabard Gardens, Bermondsey: 15 columns; 15 500W GLS
  • Tooting Bec Common, Wandsworth: 6 columns; 6 500W GLS
  • Wapping Recreation Ground, Stepney: 7 columns; 7 500W GLS
Although the surfaces lighted have very low reflecting power, adequate illumination has been obtained with an installed load at an average rate of 1.25W per square yard. The use of mercury discharge lamps was an experiment: the running costs are lower, but the installation costs were considerably higher. It was thought possible that objections would be raised by the public concerning colour distortion.
Lighting: Floodlighting, Lighting: Installations

Sodium Lighting In Luton p76
Description of the installation in Luton.
Lighting: Installations

Planting The Column p77
A series of photographs taken by Mr. C. D. Griffiths, Public Lighting Assistant to the Hamstead Borough Council, Electricity Department, of the recent installation of improved street lighting. Steel columns, made by Bromford Tube Co. Ltd., are shown being installed. In order to overcome a number of obstructions found underground, it was necessary to supply a quantity of specially manipulated roots.
Lighting: Columns, Lighting: Installations

Gas Street Lighting Improvements p78
Description of new gas installations in St. Helens and Feltham.
Lighting: Installations

Leighton Buzzard's Ten Years Contract p79
Description of new installation in Leighton Buzzard.
Lighting: Installations

Better Lighting In Coventry p79
Brief description and picture of a new installation in Coventry.
Lighting: Installations

Recent Electric Installations p80
Brief description and pictures of installations in Hebburn, Luton and Jarrow.
Lighting: Installations

Gas-Lighted Traffic Signs p81
A number of gas-lighted traffic signsed have been installed in Teignmouth. The lamps are fitted with one No. 2 mantle, and are kept alight during the hours of darkness.
Lighting: Signs

L.C.C. p81
The London County Council are very large consumers of Electric Lamps and have a completely equipped Laboratory for Photometry and Electrical Testing. A contract has been placed with Siemens Electric Lamps And Supplies Limited for the supply of lamps for a further 12 months.
Lighting: Lamps

Ideas For Swimming Bath Lighting p81
Under-water illumination is becoming increasingly popular. Light source for under-water illumination should be installed only slightly below the surface of the water while the beams should be directed at varying angles below the horizontal, according to the width of the pool. The simplest arrangemetn is to place the light sources in a recessed channel built around the bath or in recesses into the walls. In both cases, heavy plate glass must be used for the front of the lamp housings. In cases where a permanent under-water installation cannot be effected, a different arrangement is illustrated. A flat mirror at 45° is used to direct the light beam through the water from a light source inverted over the surface of the water.
Lighting: Floodlighting

Gas Schemes Qualify For M.O.T. Grant p82
Brief description of installations in Stockton-On-Tees and Abergavenny.
Lighting: Installations

Good Visibility - By Day And By Night p82
Brief description and pictures of an installation in Hoylake.
Lighting: Installations

Edinburgh's Improved Lighting p87
Description and pictures of improvements in Edinburgh.
Lighting: Installations

E.L.M.A. Light Service Bureau p87
At the Electric Street Lighting Conference last month, Mr. Morley New touched on the importance of arriving at uniformity in the standards of lighting on similar classes of roads to facilitate traffic flow and prevent accidents. Mr. L. J. Davies described recent developments in lamp and lantern design. Mr. C. R. Bicknell and Mr. J. G. Christopher, pointed out that modern electric lanterns, being able to take several sizes of lamp with little or no alteration, were able to accommodate themselves to changes in lighting requirements brought about by new traffic conditions. The relation between road surfaces and illumination was dealt with by Mr. G. H. Wilson
Lighting: Lamps, Lighting: Luminaires , Lighting: Theory

Gas Lighting For After-Dark Sports
Description of gas-lighted installations used for sports:
Hampton Public Baths: A new installation at this outdoor swimming pool where Twickenham Borough Council have installed gas floodlighting. Nine 8-light No. 2 mantle lamps, mounted on 17' concrete columns with bracket arms, are distributed around the pool. Mounting height of the lanterns is 13'6". The running costs are 7½d. per hour.
Portsmouth Rugby Football Club: Lit by gas. A battery of three 10-light parabolic flood lamps have been working for several seasons.
Kendal Rugby Football Club: Lit by gas. Four 10-light strip type projectors are used. Mounted at 6' and at intervals of 15 yards.
Saracens Rugby Football Club: Lit by gas. Four 12-light gas lamps are fitted on poles some 12' above ground level.
Highfields Open-Air Bath: Lit by gas. Twenty-four 10-light strip lanterns running at 1s. per hour.
Torquay: Lit by gas. Indoor bowls green lit by twenty lamps on each of two bowls greens.
West Hartlepool: Lit by gas. Indoor boxing stadium. The ring is lit by four 5-light gas lamps, each with 7" deep enamelled steel reflector.
Lewisham Club: Lit by gas. Bowling green. Lit by twenty-four gas lamps, each which as six No. 2 burners. Special reflectors are fitted.
Lighting: Floodlighting, Lighting: Installations

Mercury Lamps For Kingston-Upon-Hull p90
Details of a mercury installation in Kingston-Upon-Hull.
Lighting: Installations

A Gas Exhibit At Glasgow p90
Details of Foster And Pullen's forthcoming exhibit at the APLE Conference in September. Both the Arcturus and Alpha lanterns, in sizes suitable for Group "A" lighting, will be shown. The Arcturus circular suspension lamp, is available from 1 light or 15 light cluster, and has been appreciated for its robust construction and consequent long life. It has been widely adopted for long-term contracts where maintenance costs are required to be kept to a minimum. The superheater burner has separate primary and secondary air supplies and there are cleaning plugs to the gasways; the enamelled steel shade can carry the "Registered Back" reflector (reg. des. 797495 of 27/10/34) in "Staybrite" steel and the "Isolight" under-mantle reflectors, while the "Globe" under-mantle reflector is available for fitting inside the globe of the 5, 6 and 7-light sizes; Holophane refractors may be used with these lamps. The lanterns have easy access and dual-feed burners are available for reduction of light by controller at pre-determined times. All makes of clock controllers are supplied and Newbridge "Comet" ignition fitted to order.
The Alpha rectangular suspension lamp, available with 6, 8, 10 or 12-light burners, is another unit of proved success and popularity.
APLE: Conference, Lighting: Luminaires

Trade Notes p90
A collection of brief notes concerning various deals, firm news and new street lighting installations.
Lighting: Installations

Road Lighting And Traffic Density by H. L. Juliusburger p91
Introduction: A thesis which still has to be proved in practice. Road brightness theory, with objects seen in silhouette, is likely to become the most economic system in general circumstances. This is now the basis of official recommendations. It is a necessity for the working of silhouette vision that the traffic density should not exceed certain values - otherwise the car moving ahead of the observer's car may serious hinder the detection of any object in the road. For example, an object 3' high at 150' distant, requires 400' of clear road. Therefore the traffic density should not exceed 400'.
Traffic Density: A diagram is presented to find the traffic density of roads under certain given conditions and to find the "average distrance" between two cards moving in the same direction in relation to their speed. Every road will have a "maximum speed limit" and a given maximum capacity. The distance between two cars can be taken as a fixed one and varies only with the speeds at which the cars are moving. What is the minimum length of this distance? It is dependent on two factors: braking distance and reaction time. The relationship between "average car distance", speed and traffic density is given in the diagram. The diagram gives a complete picture of all traffic conditions for a mile of straight road.
Influence On Silhouette Effect: The importance of studying traffic conditions on a road, before planning a road lighting installation, is accepted. The present classificaiton of roads is tacitly based on such conditions and their influence on lighting schemes is obvious. The proper working of silhouette demands a comparitively long stretch of empty road. For it to work the respective minima of empty road have to lie ahead:
At 60 MPH ... 700'
At 30 MPH ... 315'
At 15 MPH ... 100'
Thus in the case of 700', at 60 MPH, the corresponding car density is 440 cars. If there are more cars passing over the mile per hour at this speed, a road lighting installation working on silhouette effect is no longer safe, whereas if there are less, silhouette effect in underhindered.
Influence On Direct Visibility: It would be desirable to see the successful application of the second illuminating principle, direct visibility, below such values. Unfortunately, however, only in theory is there a clear cut boundary.
Each principle can be expressed simply as follows: in the case of silhouette effect the object is seen against a background and in direct visibility on a background.
At certain speeds below certain car distances the proper working of silhouette vision may be seriously hindered by the presence of a car on the road which forms the background. This means that any object runs the danger of appearing against a vertical background with entirely different brightness properties instead of against the road surface. The direct visibility principle might be defined as making the obejct detectable on the vertical background of the moving car ahead.
Resulting Critical Car Distances: At 60 MPH the minimum car distance for silhouette vision in 700' and the maximum car distance for direct visibility is 145'. The gap inbetween the two can accordingly be dealt with appropiately if lighting for mixed conditions is provided.
Conclusion: Traffic density should be taken into account when planning lighting. A Traffic Census or similar should be taken during the hours of 4:00PM to midnight. Then a decision should be made to which road lighting condition the road applies. Traffic density conditions vary a great deal during the day, so the installation should comply to the worst conditions. The technical importance of classifying road according to the principles applicable lie in the fact that for direct visibility light would have to be thrown in the direction of traffic flow. Such an installation would have a benifical influence on glare. For "mixed conditions" the gap between minimum limit for silhouette and maximum limited for direct is narrowing down with falling speed limit and if 30MPH is imposed both limits lie very close together and for roads through towns the Traffic Density Diagram might show that silhouette principle is preferable to the direct visibility principle.
Lighting: Theory

Hereford's Improved Gas Lighting p94
Details of a gas installation in Hereford.
Lighting: Installations

L.C.C Jubilee Celebrations p94
Picture of the floodlighting carried out at County Hall. The fountains were also floodlighted.
Lighting: Floodlighting, Lighting: Installations

Sheffield p94
Six street lighting lanterns with 500W lamps have been used to light a chidren's playground on one of the Corporation's housing estates. The laterns serve to provide a reasonable amount of light over the whole of the area as well as excellent intensity on the playing area.
Lighting: Floodlighting, Lighting: Installations

Screening Of Lights p94
There needs to be a simpler method than the use of blinds and black paint on windows to obscure lights during war time. An idea has recently been tested at a Luton factory which combines coloured windows with orange coloured electric lamps. It is claimed that no illumination escapes any windows. The scheme was first tested in France in aerodrome buildings.
It was found that with windows covered with a preparation resembling carnish of a blue colour, 75% of daylight was admitted, whilst the orange lamps give a satisfactory illumination by night. The orange lamps have to be sepcially made but should not exceed the cost of ordinary filament lamps.
There are many advantages: it enables wokr to be done in the daylight without artifical lighting; obviates the risk of disorganisation which might follow a sudden extinction of lights.
It is expected that lamps and paint will be soon available in large quantities.
Lighting: ARP

Rythmatic Control - The First Installation In Great Britain p95
The first installation in Great Britain of Rythmatic Control has been placed in service in Falkirk, Scotland. It is designed to enable numerous public services to be controlled from a central point by means of push buttons. Up to 24 different switching operations are possible. Of primary importance is the control of street lamps. At Falkirk, some 400 lamps are controlled and can be switched "on" at dusk; "off" except for pilot lamps at midnight; and completley "off" at dawn.
Other services such as tariff "change overs", electric water heating, space heating etc. can be controlled if required.
Particularly important are ARP services, such as the calling-up of wardens, nurses, firemen and the like.
The equipment consists essentially of a control panel carrying the push buttons and a red indicator for each facility. Associated with the operating button is the injector equipment, which sends out audio frequencies as a train of timed impulses according to the signal code. The system uses four audio frequencies and six different impulse timings. The equipment is normally located in the power station.
Mounted in the street lamps or other individual items to be controlled is a special relay which has two principle components: (1) A tuned circuit which responds to one of the four audio frequencies and (2) Two swinging armatures with natural periodicities corresponding respectivley to two of the six impulse timings, but which can only be fully deflected by repeated impulses at the correct periodicity.
The relay is fitted with 15A contacts and operates at a very low voltage.
Rythmatic Control operates over existing power networks and it does not matter whether the supply is AC or DC.
The Falkirk installation was hatened into service so it could be used in connection with the important Eastern Scotland "black-out" which commenced an hour or two after the Rythmatic Control equipment was put into service.
Lighting: ARP, Lighting: Control

Street Lighting Notes p96
Brief description of the installations at: Abertillery, Aireborough, Amersham, Ballymena, Battersea, Beccles, Broadway, Buckley, Burgess Hill, Carlisle, Chard, Chipping Campden, Cirencester, Coventry, Dalkeith, Darlington, Derby, Dungannon, Durham, Ellesmere, Glasmorgan, Greenock, Grimsby, Hemel Hempstead, Herts, Heskin, Hoylake, Ilkley, Leven, London, Morley, Notts., Paignton, Paisley, Poplar, Prestatyn, Reigate, Retford, Rothesay, Rothwell, St. Helen's, Saltcoats, Scotland, Sedbergh, Sherringham, Sunderland, Treharris, Usk, West Ham, Wigan, Willenhall, Wimbledon, Windsor, Worsley and Yorks.
Lighting: Installations

Hospital Lighting Equipment p98
There are many requirements in hospitals and sanatoria that call for specialised lighting treatment.
Ward Lighting: At the Royal Free hospital, Grays Inn Road, there is an excellent system of ward lighting consisting of white opal pendants and brackets, which provide well diffused illumination from the main light source for general requirements, while for night supervision a concealed lamp emits a subdued light in the region immediately beneath the lighting unit. These fittings employ either a 40-60W Osram lamp for general lightign and a 15W pygmy lamp for subdued lighting. Another type of ward lighting unit (which has the approval of the London County Council) consists of a pendant fitting carrying a 10" white opal bowl arranged for one 60W and two 15W Osram lamps. The latter are arranged to provide indirect night lighting when the main light source is subdued. Pilot lighting systems for use as ARP lighting can have low intensity blue lamps installed under central control. Another ward fitting is the bed-head type: it is fitted with morocco pattern glassware and has a switch at the base. It amply suffices for bed illumination and staff attention to patients. At the Redhill County Hospital, Edgware, another method of ward lighting has been adopted: it serves as general ward lighting and bed lighting. However it does not provide night or pilot lighting.
Operating Theatre Lighting: A shadowless operating theatre fitting has many outstanding featuers. An average light intensity of 600 foot candles is mainted within the limits of the 12" diameter circle when fitted with a 150W Osram lamp. Such high efficiency is due to an entirely new form of optical system. The unit will also provide a certain amount of diffused light well beyond the circle of maximum intensity - this is to reduce eyestrain caued by concentration on a localised area of high relative brightness.
Emergency Lighting: This is embodied in the unit. This produces the same beam characteristic as the main system. The lamps and all other component parts are quickly and easily accessible from the bottom of the unit; the contour of all external parts is made smooth to minimise dust collection; rapid cleaning is possible from floor level. The lighting unit is balanced so it will remain at any desired angle without clamping; an enclosed counterweight is supplied which permits vertical displacement without clamping; the diffusion of the light patch is such that there's no critcal focal point which requires refocusing.
Lighting: ARP, Other

Change Of Address p98
Change of address for GEC Hull branch and Philips Lamps in London.
Lighting: Manufacturers

Adverts: The General Electric Co., Ltd, William Sugg And Co., Ltd., Walter Slingsby and Co., Ltd., Siemens Electric Lamps And Supplies Ltd., British, Foreign And Colonial Automatic Light Controlling Co., Ltd., Gowshall Ltd., Standard Telephones And Cables Ltd., Sangamo Weston Ltd., British Commercial Gas Association, The British Thomson-Houston Co. Ltd., Philips Lamps Ltd., Metropolitan Vickers Electrical Co. Ltd, British Electrical Development Association, Inc, The Horstmann Gear Co., Ltd., Johnston Brothers (Contractors) Ltd., REVO Electric Co., Ltd., Peebles Co., Ltd., Hobbs, Offen And Co. Ltd., Northampton Polytechnic, Holophane Ltd., Public Works Exhibition, Automatic Telephone And Electrical Co., Ltd., Gas Meter Company, Foster And Pullen Ltd., Bromford Tube Co. Ltd., James Keith And Blackman Co., Ltd. and Concrete Utilities Co., Ltd..