150a - Off Hallam Way, Langley Mill

150a. Off Hallam Way, Langley Mill Installed within a car parking area of the former Hallam Plastics works is a twin-armed 25 ft (7.62 m) sheet steel lighting column supporting a couple of GEC Z8430 lanterns. Interestingly, although both lanterns are likely to be of the same age, the left-hand example features the revised bowl design that was introduced in the wake of phosphor-coated elliptical mercury vapour (MBF) lamps entering production (the suffix 'CM' being added to the lantern part code at the time, for 'Corrected Mercury' lamps), whilst the right-hand lantern retains the older style bowl, which featured a series of concentric refractors, and was optimised for uncoated tubular mercury lamps. The lamp type and wattage fitted to the lanterns these days is unknown. With the plastics firm having gone into administration in 2018, this installation may disappear in the not-too-distant future, if and when the site is redeveloped.

This is the only lighting installation in the car park; there is nothing to suggest that additional columns once existed here.

The Z8430CM (on the left) bowl is (marginally) deeper than the Z8430's bowl is.

An elliptical lamp of some repute can be seen within the lantern.

The same is true for the Z8430.

A single-arm column of a similar style to that seen above exists on an entrance to another derelict factory complex on Milnhay Road. Although this site was operated by a separate company, aerial photography of the area shows a gated roadway linking both sites, suggesting that they were part of the same company in the past. This too supports a Z8430.

A bracket with considerable outreach is fitted to this column.

The close-up view of the lantern demonstrates how the concentric refractors would have optimised the beam produced by the uncoated lamp.