This Section of the Catalogue is devoted to a comprehensive range of scientifically designed lighting units for the efficient distribution of the light emitted by the various types of lamps now in general demand. The individual characteristics of each type of lamp have been carefully considered in the production of each unit, and these designs are the result of extensive experimental research and practical experience. The maximum utilisation of the lumen output of the different light sources has been the chief aim in the design of REVO Lanterns. Design and selection do not alone, however, guarantee satisfactory lighting, for the planning of any installation requires careful consideration of local conditions as well as actual experience in the laying out of such schemes. In August 1937, the Ministry of Transport published recommendations for the lighting of all traffic routes in the Final Report of their Departmental Committee on Street Lighting. (See also British Standard Code Of Practice CP1004:1952). In this Report roads are divided into two categories, Group A, which includes all the main traffic routes and for which the standard of lighting should be such as would render the use of automobile headlights unnecessary in all circumstances (with the possible exception of fog) and Group B, which includes all other roads of secondary importance.

Two requirements for the lighting of Group A roads, with lanterns of the non-cut-off type, are a mounting height of 25ft. and a normal spacing not exceeding 150ft., preferably 120ft. The spacing may, however, have to be considerably modified to suit the recommendations for siting at bends and road intersections, to which special attention must be paid. For Group B roads the mounting height should be 15ft. and the normal spacing not greater than 120ft., preferably 100ft., but here, again, the siting is of great importance. The REVO Staff of lighting engineers is available for making surveys of roads and for planning schemes in full compliance with the recommendations of the Final Report without obligation.

For Group A roads the total lantern lumens per 100ft. linear of road should be between 3,000 and 8,000 for carriageways up to 40ft. in width and this calculation should be based upon the average lumen output during the rated life of the lamps. For Group B roads the corresponding figure should be between 600 and 2,500. It is not intended that the lumens per 100ft. should be regarded as an absolute figure of merit, since there are so many other factors which influence visibility in street lighting such as glare, reflection properties of road and surroundings, etc., but merely as a guide to determine what size of lamp to use for a given installation.

One of the outstanding post-war developments in street lighting has been the use of fluorescent tubular discharge lamps. The Revo SOL-ETERN lanterns have been specially designed to use these light sources and numerous installations throughout the country have clearly demonstrated their unique qualities. The C12492 lanterns, each having two 5ft. 80 watt lamps, will provide excellent visibility and a high degree of uniformity in road brightness when spaced and sited in accordance with the requirements for Group A roads, although the lumens per 100ft. are near to the lower limit of the recommended range.

For higher standards of lighting the C13034 lantern for three 5ft. 80 watt. and the C12572 lantern for four 5ft. 80 watt. lamps are available.

For Group B roads the C12666 lanterns for two 2ft. 20 watt. and C12667 for two 2ft. 40 watt. almps are obtainable. These may be supplied with brackets for inclining the lantern to provide more extensive coverage when used on wide thoroughfares.

For Civic Centres, main shopping streets, promenades and other roads where lanterns of ornamental design are required, attention is drawn to C13428 for four 5ft. 80 watt. lamps and C13612 for four 2ft. 20 watt. or 40 watt. lamps.

Of particular interest of the C13738/40 "Eastbourne" fittings. These are essentially floodlighting units designed for mounting horizontally on the walls of buildings bordering the road, with the axes of the lamps parallel with the road. They are particularly suitable for streets with more or less continous buildings, of 25ft. or greater height, on both sides. When mounted at a height of 25ft. with a projection of 6ins. to 1ft. from the building line they are inconspicuous in the daylight and, if properly spaced, will provide remarkably uniform and glare-free lighting by night. The average spacing must be appreciably less than that normally adopted for street lighting lanterns, but hte increased cost involved is off-set by the savings in the cost of standards and brackets. Very effective results can be achieved with this form of lighting, especially in streets where narrow footways prevent the erection of standards.

Very efficient light control from street lighting lanterns is obtained by means of Revo patent lens dome refractors. The prisms are accurately formed and specially designed to provide effective light distruvtion, while at the same time avoiding objectionable glare and unnecessary waste of light.

These refractors are supplied with a wide range of fittings for both Group 'A' and 'B' Roads, suitable for up to 1000W. tungsten filament, 80/125w. mercury or 80w. fluorescent lamps. The light distribution is normally controlled in two main beams diverging 160° in azimuth, but refractors providing a symmetric distribution may be supplied if specially required. For Group 'A' Roads, refractors with 180° beam divergence are avilable for installations where lanterns are mounted centrally over the carriageway.

The "Kleen-Prism" dome refractor has been produced to simplify the problem of maintenance, and is available with all lanterns designed for up to 200W. tungsten or 125W. mercury lamps. The phenomena of both refraction and total internal reflection are employed to obtain efficient light control by means of accurate prisms formed on the outer surface only of a single piece inner glass dome. These prisms are completely protected by a clear outer glass sheath securely sealed to the inner dome, thereby exposing only smooth surfaces to the atmosphere, which may be easily cleaned by the maintenance staff.

"Kleen-Prism" refractors are particularly suitable for open type lanterns such as C12423 or C13222.

Back to REVO Electric Lighting Equipment