Bradford Council had reached the point where they faced a dilemma on how to deal with lamp replacements for their stock of 35W SOX lanterns; on 5m columns with large spacings. As SOX lamps are so expensive and the price of control gear massively inflated, the team needed to find an alternative lantern that was more cost effective to install versus a brand new SON fitting. They had to reduce energy consumption whilst still providing the right lighting levels and achieve a good night time aesthetic.
Two areas were used in the trial, a residential cul-de-sac where 3 x 20W LED AIR1 units were installed and another, narrow residential road with substantial spacings where 5 x 30W units went up. It was important to compare the previous look and feel of the light output to the new scheme.
Initially, due to the wide spacings and low wattage, the team thought LED might give a somewhat patchy scene, but in fact it was much better than expected with good uniformity. The overall public view was that the lighting was much better in both areas however the 30W location but due to the perceived increased brightness of white light and small number of residents felt the road was over lit.
We wanted to find a cost effective lantern but also, because SOX replacement lamps are so hard to come by and expensive, something that can be used as a maintenance lantern – a cost effective lantern that will do the same job well and keep the public happy. We are also conducting this small scheme as a trial of Direct Drive technology; reviewing the impact on the environment and the night time scene. Checking brightness, uniformity and glare from a real-life perspective. We weren’t designing to a level but wanted to find out the real impact which we thought would be worse but actually found to be much better, even with the reduced power consumption.
We dealt with Chris at INDO who was very approachable and knowledgeable. He came in and provided us with a sample, did a demonstration and explained that we could do a trial. It was very easy to deal with INDO and the results have exceeded our expectations.
Allun Preece, Principal Engineer
Facts & Figures
|35W SOX lantern
with standard gear
|20W INDO AIR1
with Direct Drive®
|30W INDO AIR1
with Direct Drive®
|Burn Hours||4,125||(20/20 PECU) 4,086||(20/20 PECU) 4,086|
|Energy cost per annum||£26.81||£7.76||£12.26|
|Maintenance per annum*||£7.50||£0||£0|
|Total cost per annum||£34.31||£7.76||£12.26|
|Savings per annum||–||£26.55
* Maintenance costs calculated and amortised assuming a 4-yr lamp replacement program and do not include electrical testing or cleaning.