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ilp archive : journals
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public lighting no. 5 vol. 2
March 1937
- Editorial p3
- Coronation Illumination Devices: These will be on a scale exceeding those of the Jubilee Celebrations
of 1935, floodlighting being considered the simplest and most effective and many manufactures have
made immense ranges of illuminating devices including ornamental street lighting;
Black Out Grievance: a complaint about part-night lighting "as a ratepayer he bears
his share of the lighting rate, and naturally feels aggrieved that this particular
amenity should be denied him in the small hours, while his more fortunate friends
in the same neighbourshood who live nearer to, or adjoining, a road which is much
used for traffic daily, suffer no such depreivation. The correspondent makes the
very reasonable point that, while there may be some financial justification for this
action, yet there remains the question of the householders' protection from nocturnal
marauders, whos nefarious practices are likely to become more active in those
roads in whcih a "black-out" exists after midnight." A possible solution
is by the extinguishment of alternative street lamps, or by minimum lighting
generally; Air Raid Precautions: This should be the sole responsibiltiy
of the Public Lighting Engineer [although it's interesting to note that "much
activity is being displayed by local authorities" at this early date];
Street Lighting Progress: 36,000 discharge lamps are now used
in the UK which is greater than in all the leading countries abroad put together. In
London alone, over 300 miles of streets are so lighted while over 200 local authorities
are employing this "accident-proof" type of lighting.
- Lighting: Events, Lighting: Levels,
- New Lamp Development p4
- The GEC have introduced their new high pressure mercury lamp (later MB) at the British
Industries Fair. Rated at 80 and 125W, this new "Osira" mercury electric discharge
lamp has an extremely high efficiency and gives three times as great light output
as a tungsten lamp of equivalent wattage. It is similar in shape to the ordinary
tungsten electric lamp and is internally frosted. To avoid confusion with the
tungsten type of lamp it is fitted with a three-pin cap.
- Lighting: Lamps
- Lighting Authorities Can Help Road Safety p4
- "I am sure that if we are to reduce this appalling loss of life on the
roads, the loss which, in any one year, is greater than the whole of the loss of life in
the two years eight months of the South African War, it will have to be through the
co-operation of manufacturers, suppliers, and public lighting authorities." - Alderman
J. Chuter Ede, M.P. for South Shields.
- Lighting: Social Comment
- Bottled Gas p4
- Among the proposed illuminations at Coronation time at Wallasey are to be displays
in which compressed gas will be used. This is being increasing used owing to the enterprise
of the Corporation's Gas Department.
- Lighting: Events
- Coronation Displays p4
- Details of gas floodlighting schemes of various buildings including
Gas Industry House (on the direct Coronation Route), St. James's Park
(where 300 concealed gas projectors will be used) and
Devonport Park, Plymouth; other displays are planned at Edinburgh, Stoke,
Guernsey and other towns.
- Lighting: Events, Lighting: Floodlighting
- Road Lighting: Counties And Road Fund Grant p4
- In the report of the Executive Council to the County Councils' Association on the
23rd March, reference is made to the efforts of the Council, so far without success,
to obtain a Road Fund grant in aid of such road lighting as may be undertaken
by County Councils. The view of the Minister of Transport is that he does not
possess any power to comply with the request.
- Lighting: Funding
- New Street Lighting In Fulham (London, S.W.) by W. C. Parker Borough Electrical Engineer p5-6
- Full details of the Fulham main road installation.
- Lighting: Installations
- Bicycle Allowance For Lamplighters The Times January 5th p6
- "Palmerston, when Queen Victoria once rebuked him for being late,
made bold to reply that he could not run like a lampligher." This
quote is still being made today, but only rarely and usually by elderly people.
It belonged to a past age when lamplighters really did run but has little
application to now when lamplighters ride bicycles. The lamplighers of
Southampton have taken issue with their employers over the allowance that should
be paided for using their own bicycles and performed a "go slow" by walking
their rounds at the weekend. The lampligher's bicycle allowance has been a local
agreement between employer and lamplighter and has not caused any problems in
the past.
- Lighting: Equipment
- Bristol's Improved Street Lighting To Cost £120,000 p6
- Details of a proposed improvements to Bristol's lighting.
- Lighting: Installations
- Illumination Measurements p7
- During the last few years, methods of illumination measurement have been revolutionised.
The human eye might be said to have been designed as a
seeing device but it could never be classified as a measuring
device. Until recently, practically all methods of illumination
measurement consisted of comparing a surface of known illumination
with another surface whose illumination was unknown - this comparison depended
upon the human eye. With the advent of the "Barrier" type photoelectic cell
this whole situation has changed. This develops sufficient current in even
moderate light intensities to operate a milliameter without the use of
external batteries or amplifying devices. When comparisons are to be
made between illumination of different colours, then the colour sensitivity
of the cell becomes important and the best procedure is to employ a colour
filter in conjunction with the cell, which eliminates the invisible radiation
and reduces the balance of the radiation to a proportion so that the total
response of the cell is equivalent to that of the human eye. Indoor
illumination is prodvided for two reasons: for seeing and for beauty. Measurements
are them considered:
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0-3 foot candles
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Inadequate
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3-10 foot candles
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Suitable for stairs, hallways, warehouses and auditoriums
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10-20 foot candles
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Suitable for retail stores, school class-rooms, general offices and
factories producing rough products
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20-30 foot candles
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Suitable for drawing and sewing rooms, factories making average products
and offices doing close work.
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30-50 foot candles
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Suitable for factories producing bulk products and for inspection departments
examining carefully fine articles
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- Outdoor artificial illumination is provided for safety and
convenience as in the case of roads and airports; to prevent
theft or sabotage as in the case of works; and for advertising
as in the case of floodlighting. [Note: "beauty" is not considered
in this context.]
- There is some controversy as to the correct method of illumination
especially of roads. While some people are in favour of the measurement
of contrasts, shadows etc., it is still generally agreed that
average illumination in terms of foot candles is what is more
desirable. In making such measurements, due thought must be given
to the angle of incidence of the light upon any given surface
and the colour of the light source.
- (Two units are pictured and described. Includes Spectral
Response Curves for the eye and the cell.)
- Lighting: Equipment
- Better Gas-Lighted Streets p8
- Yearly statistics published by the gas industry show that many
lighting authorities in our large towns and cities continue to rely on
gas lighting. Of the fourteen districts named, there have been an increase
of 10,000 lamps from 1935.
- Lighting: Installations
- Some Aspects Of The Street Lighting Problem by S. English, D.Sc., F.I.C., F.Inst.P. Holophane Research Laboratory p9
- Excerpts from a Paper read at a meeting of the Illuminating Engineering Society,
held at the Institution Of Mechanical Engineers, London, on the 9th March 1937.
- [A very interesting paper which is one of the first published criticisms against
the new road surface brightness theory. The full paper should be found as these
were just notes made at the meeting.]
- Uniform Illumination
- 1. Recalled the early work by A. P. Trotter and stated
"the avowed aim of the early workers in this field was to produce a near as was
commercially possible uniform illumination along the roadway, a diversity factor
of less than 10 to 1 being regarded as reasonably good, while with non-directing
equipment and the relatively wide spacing then adopted the diversity ratio of
reached 40 to 1."
- 2. In the days before tarmacadam roads, this aim was excellent, as
the road surfaces were much lighter in colour and had much more difusely
reflecting surfaces than modern roads e.g. rough concrete, granite sets.
- 3. Pedestrian could use direct vision and motorist could use silhouette vision to see near and
far objects respectively.
- 4. These early workers also realised that directional lighting needed care,
since the indiscriminate projection of intense beams of light along a road was liable
to give rise to uncomfortable glare unless the angle of elevation of the beam
was carefully controlled. In well designed directional fittings, the main beam
was generally projected at 15° below the horizontal.
- 5. The adoption of this
angle allowed space-height ratios up to 8. Attempts to reduce the cost of the
installation and maintenance, by increasing the space-height ratio, either by
increasing the spacing or decreasing the mounting height, involved the use of higher
beam angles, with a consequent increase in glare.
- Road Surface Brightness
- 1. The widespread use of tarmacadam and asphalt, which take a failry good polish
after being subjected to heavy motor traffic, has led to the resurrection
of theories of street lighting based on road surface brightness.
- 2. During recent
years the important of high and even road surface brightness has been
emphasised in this country and in some quarters almost elevated to a creed,
apparantly being regarded as the one and only characteristic of a street lighting
installation worth of attention. For instance, the question of glare appears
to be completely ignored, thought it is obvious that strong beams of light
impinging on the eye only a few degress from the normal line of sight must
result in an impairment of vision.
- 3. The statement is made that a polar curve of a particular type
is necessary to produce high and uniform road surface brightness:
- No body of evidence to support such a statement has been published.
- It is generally agreed that the brightness of the road surface is more
a function of the nature of the surface than of the precise form of the
polar curve.
- Brightness distribution on a road surface can be completely altered
by a simple repair or even a shower of rain.
- 4. In towns and popular areas where pedestrian traffic is heavy and where the
road surface only forms a relatively small proportion of the background, it
seems obvious that different form of lighting could be adopted. For heavy
pedestrian traffic uniformity of illumination is of greater importance, for
the motorist it is road surface brightness.
- Real Aim Of Street Lighting
- "The aim of street lighting is not to produce uniform illumination
along the roadway, nor to produce uniform and high surface brightness, nor
to eliminate glare, nor to produce a constant degree of glare, but to simply
to enable road users of whaterver class they belong to see clearly whatever they
need to see, more particularly to see obstacles and circumstances that
may lead to danager." It does seem neccessary to say this in order
to bring some specialists down to earth and to get them to realise that there
is something in the points of view that are held by other people regarding the
means by which good street ligthing may be achieved.
- The pedestrian needs to see people and things generally at a relatively close range.
- The motorist needs to see clearly and quickly in the near neighbourhood of
his car as well as objects on the road a quarter of a mile away.
- Experimental Work
- "If an attempt is made to determine in an experimental manner
what constitutes good street lighting, innumerable difficulties crop up:"
- Psychological - what is good street lighting is a matter of opinion and it
is difficult to get agreement. Even if agreement is obtained, it is still more
difficult to get a numerical evaluation of the goodness of an installation.
- Physical - the enormous number of variables e.g. mounting height, space
of units, lumen output, type of light source, light distribution of fittings,
cut off, nature of road surface and its condition.
- Lighting: History, Lighting: Distribution, Lighting: Theory
- Representation Of Street Lantern Characteristics by R. Maxted, B.E.Elec., B.E.Mech. p10
- Excerpts from a Paper read at a meeting of the Illuminating Engineering Society,
held at the Institution Of Mechanical Engineers, London, on the 9th March 1937.
- Suitable diagrams for representing lantern characteristcs must by used to (1)
investigate the fundamental factors influencing visibility and (2) allow the
specification of a street lighting installation. "In street lighting, the goal
can only be approximately defined as visibility; and the degree of visibility necessary,
or the extent to which it has been achieved, is entirely a matter of the experience
and judgement of all classes of road user."
- Objective Factors To Be Analysed
- Installation design must be examined from two points of view: (1) Providing
suitable brightness of backgrounds and objects and (2) Avoiding or limiting the
neautralising effects of glare. Unfortunately it is light which has been projected
towards the observer for the purpose of producing surface brightness whcih may also
give rise to glare."If it is proposed to modify a lantern distribution with
a view to reducing glare, then the surface brightness must also be changed, and an
optimum lantern design can be obtained only by a compromise between the requirements
for surface brightness and glare."
- Glare And Cut-Off
- Glare cannot be described satisfactorily in terms of brightness, for whilst an
excessive source brightness may result in discomfort glare, disability glare is
a function of the intensity and the angle of light projected towards the eye. Similarly
repetitive glare effects arise mainly from variation in these factors produced by
movement of the observer.
- The Specification Of An Installation
- "In an analytical survey of street lighting, the records should cover
the lantern characteristics, the distribution of brightness, and the location of
units." A complete account of the lantern distribution is given by the iso-candle
diagram. It seems advisable to seek a specification based entirely upon the installation
layouts and the lantern characteristics. "Thus the lantern distribution would
be determined by the minimum size of the bright patch to be produced by an individual
lantern when the road surface is in the least favourable conditions. The
installation layout would then place the lanterns so that the bright areas coalesced
to give satisfactory overall surface brightness from the normal path of the observer."
- Lumen Basis Of Lantern Curves
- While the 400W HPMV lamp gives an initial output of 18,000 lumens, the curves
of lantern performance should be based upon a perfectly clean lantern and a lamp output
of 12,000 lumens. With the lamp giving an average of 16,000 lumens over life, this
allows a factor of safety of 33% to cover all other contingencies such as variations
in road surface, reflectivity, efficiency of cleaning, accuracy of lantern erection etc.
- Conclusion
- Sources of different colour should not be mixed indiscriminately in a survey
aimed at the study of lantern distributions.
- Lighting: Theory
- Modern Gas Street Lighting Installations by W. J. G. Davey, B.Sc. and A. R. McGibbon, A.M.I.E.E.
p11-16, p21-28
- Enitre copy of the paper given at the conference. Originally
contributed for the Lighting Section of the Society of British Gas Industries.
- Lighting: Luminaires, Lighting: Specifications, Lighting: Theory, Lighting: Installations
- Folkestone p20
- Arrangements for the forthcoming conference in Folkestone. Also includes new members,
junior members and associates.
- APLE: Conference, APLE: Organisation
- Night Photography p20
- Recommendation for Messrs. Hobbs, Offen & Co., who carry
out night photography of installations for manufacturers.
- Lighting: Photography
- Coronation Floodlighting p29-30
- Descriptions of various electrical schemes planned for the Coronation.
"Electricity is rapidly progressing, largely owning to the improvements
in generating plant and efficiency in working, and a consequent reduction in
operating costs." Discussion of the plans of various authorities of
the floodlighting of public buildings, memorials, institutions etc.
BEDA have sent out a circular
stressing the potential advantages of electricity generally. The article
notes how many temporary floodlighting schemes are becoming permanent. Includes
plans of several local authorities.
- Lighting: Events, Lighting: Floodlighting
- Newcastle Coronation Street Decoration Lighting p30
- Newcastle Corporation will installed 132 large decorative lanterns for
the coronation. The lantern, which is of rectangular shape, is by the
GEC It is 4' high and 28" wide.
- Lighting: Events, Lighting: Floodlighting
- Park Illumination by a London Parks Superintendent p30
- Suggestions for the increased use of parks in the winter months.
This includes lighting: "So far, with some exceptions, the attempts
at artistic park and garden illumination have been of a crude order,
accompanied by a considerabl amount of paraphernalia and various
contraptions, which, in the day time at any rate, are often in the way,
highly dangerous and far from being beautiful... It is sincerely to
be hoped, however, that we shall be spared in such lighting systems the
ghastly effects which are produced by mercury vapour lamps in the
countenances of otherwise pleasant looking individuals."
- Lighting: Social Comment
- Street Lighting In Romford: Competitive Supply by F. V. Appleby, M.Sc., A.M.Inst.C.E., M.Inst.M. & Cy.E p31-p33
- Eastern District of the Institution of Municipal and County Engineers, Romford, March 11th, 1937
- Description of the requirements of the new installation. Includes the
The Urban District Council's Specification for street lighting. (See "Romford" section in the link.)
- Lighting: Installations
- Lighting News From Members p34
- Details of various installations sent in by members of the association.
- Lighting: Installations
- Obituary p34
- Obituary of Charles F. Blincoe, the Gas Manager and Public
Lighting Superindendent for Middlesbrough.
- Lighting: Personnel
- Street Lighting News p35
- Brief details of various installations.
- Lighting: Installations
- Adverts:
Philips Lamps Ltd.,
William Sugg And Co., Ltd.,
Walter Slingsby and Co., Ltd.,
South Metropolitan Gas Co.,
The British Thomson-Houston Co. Ltd.,
Radiovisor Parent Ltd.,
Siemens Electric Lamps And Supplies Ltd.,
British Commercial Gas Association,
Gowshall Ltd.,
Foster And Pullen Ltd.,
Concrete Utilities Co., Ltd.,
The Horstmann Gear Co., Ltd.,
British Electrical Development Association, Inc,
Gas Meter Company,
Public Works Roads & Transport Exhition And Congress,
W. Parkinson and Co.,
Bromford Tube Co., Ltd.,
James Keith And Blackman Co., Ltd. and
The General Electric Co., Ltd.
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