Specification Clearmain 9517
Use
Designed for use in Groups A1 and A2 at mounting heights of up to 35ft. and in Group A3
at mounting heights of up to 40ft.
Lamp
175-watt Osram Golden Linear Sodium lamp.
Mounting
The Z9517 side entry lantern requires not less than 5 in. of horizontal unthreaded 1¼ in. B.S.P.
When fully home two 3/8" diameter Allen type grub screws grip the barrel. Water running
along the barrel is prevented from entering the lantern by a water baffle.
Lantern Body
One-piece light alloy die-casting. The body carries a white enamelled over-reflector,
lampholders, lampholder clips and porcelain terminal block. An earthing screw and porcelain
cable cleat are provided.
Lampholders
Two ceramic insultated bi-pin holders.
Optical System
Light Control is provided by two 'Perspex' refractor plates. The prismatic sides of the
plates are bonded one to each inner side of a 'Perspex' bowl. Both inner and outer surfaces
of the bowl are smooth for easy cleaning. The ends and sides of the bowl are lightly
obscured.
The bowl is hinged to the lantern body and fastened by means of two stainless steel catches.
A tropicalised felt gasket between the body casting and bowl ensures a weatherproof seal
when the lantern is closed.
Weathering Finish
The alloy used is specially selected for its resistance to corrosion. Further protection is obtained by the
use of a pre-treatment primer and stove enamel top coat.

[1] Principle conical polar curve.
[2] Principle vertical polar curve and polar curve in vertical plane parallel to street axis.

The above iso-candela diagram is based on an average lamp light output through life from a
175-watt Osram Golden Linear Sodium Lamp (20,000 lumens average, applicable at time of print).
Light flux in lower hemisphere (lumens) |
13,200 |
See CP1004 Tables 10-16 |
Downward light output ratio |
0.66 |
No limits specified |
Angle of elevation of upper limit of beam |
79° |
75° must be within beam |
Angle of elevation of lower limit of beam |
67° |
75° must be within beam |
Peak intensity ratio |
2.13 |
1.8 to 4.0 |
Maximum intensity ratio in the zone from 0° to 30° |
1.18 |
0.3 to 1.7 |
Minimum intensity ratio in the zone from 0° to 30° |
1.04 |
0.3 to 1.7 |
Maximum intensity ratio in the zone from 0° to 30°/Peak intensity ratio |
0.55 |
0.7 Maximum |
Angle at which 1.2 intensity ratio occurs above peak |
83° |
80° to 86° |
Intensity ratio at the horizontal |
0.38 |
0.7 maxiumum |
Divergence of beam centre from the axis of the road in azimuth |
Zero |
15° Maximum |

The Z9517 side entry lantern with the bowl opened to show the lamp mounting

Sectional scale drawing of Z9517 lantern. Lantern weight: 12½ lbs. (5.7 Kg)
|