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Alpha Eight on 3571 DB steel column
atlas alpha eight
mercury fluorescent lantern

This lantern lends itself for use in City and Town centres and other areas which require a high level of illumination. Freedom from glare, for the comfort of both drivers and pedestrians are provded in addition to good colour rendering.


Special Features. Employing two lamps in tandem has the effect of creating a linear source, a feature which ensures even road brightness and is complimentary to the type of distribution and intensities required for Group A1 lighting, in accordance with CP1004, 1963, Code Of Practise.

Means of access into the lantern is through a hinged door in the lantern canopy which is sealed by a braided asbestos gasket. The plastic bowl which does not require removal for maintenance, is sealed permanently in position with a 'D' section neoprene gasket. These features ensure low maintenance, and important factor at the new mounting heights recommended by the Code Of Practise. The hinged canopy door to which the lamps are fixed provide a positive working surface when re-lamping is necessary.

Economy burning can be effected by switched off one of the lamps at midnight.

Optical System. Two reflectors are used to achieve the semi-cut-off distribution required. The lantern has a sharp runback characteristic to ensure a glare free installation.

Materials. The lantern canopy is cast L.M.6 silicon aluminium alloy. Reflectors are manufactured from high purity aluminium alloy and the bowl from clear plastic. Other parts of the lantern are manufactured from corrosion resisting alloys and stainless steel. The internal wiring is glass braided heat resisting cable. A cable cleat and terminal block are provided.

Finish. The casting is finished with a stove enamelled aluminium paint, and the reflectors are anodised.

Installation. The spigot entry is 5" in length and 1½" B.S.P. diameter. The spigot is firmly engaged by three stainless steel socket headed screws, holding it firmly in position. The hinge pins of the canopy door assembly are hollow stainless steel Sel-lok pins and the door is firmly locked in position by two ¼" B.S.W. Stainless Steel cheese headed screws.

Lamps. Two ATLAS 400 watt MBF/U Mercury fluorescent lamps.

Catalogue Number. PPC/D.2400.

Polar diagram round major axis for 2 x 400 watt MBF/U lamps with a total light output from the lamp of 38,400 lumens.
Technical Data

ATLAS Mercury Vapour Discharge Lamps:2 x 400 watt MBF/U
Average light output throughout life:38400 lumens
Angles of elevation of 90% peak intensity in principle plane:59° - 71°
Peak Intensity Ratio:1.85
70% of Peak Intensity Ratio:1.3
Intensity Ratio in 0° to 30° zone:1.47
Elevation above peak of intensity ratio of 1.2:80°
Horizontal Intensity Ratio in plane parallel to road:0.13
Angle of Azimuth of Peak:
Flux below horizontal:23000 lumens
Total circuit rating:850 watts
Mounting heights for Group A1 roads:30ft, 35ft, 40ft
Mounting heights for Group A2 roads:35ft, 40ft
Conversion factor for 1 x 400 watts + 1 x 250 watts MBF/U lamp:    0.79
Overall length:47½ ins. 120.4 cms.
Overall width:21½ ins. 54.6 cms.
Overall height:12¾ ins. 32.4 cms.
Weight:38 lb. 17.2 kg.