As a street lighting historian and collector, Iâ€™ve found this thread particularly fascinating. Luckily I discovered this discussion before a short break in Dublin, so I was able to take several pictures of the examples in Merrion Square Park and pay my respect to the remaining concrete columns in the city.
Iâ€™ve since reviewed various publications and books devoted to street lighting and discovered that the Oâ€™Connell installation (that being the concrete columns) was mentioned several times. Even Waldram, who was probably the most respected street lighting engineer and researcher in the 1930s through to the 1960s, mentioned them favourably in his cornerstone book of 1951.
By road building standards, Oâ€™Connell Street is extremely wide. This causes problems with standard street lighting, which assumes a set road width (Normal street lighting lanterns are designed to cast light up and down the roadâ€™s axis). A custom built, or a novel approach, is required, and this is what the authorities set out to do in the late 1930s.
Looking at the old pictures of Oâ€™Connell Street, it was first lit with gas, then arc lamp, and finally incandescent electric bulb. In 1938, this often-altered installation was deemed inadequate and Mr. F X Algar, who was the head of the Lighting Section of the Irish Electricity Board, was asked to design a replacement installation.
His scheme was novel in many ways. Firstly, he specified concrete columns and brackets, which were only just being used for street lighting (the first columns in the UK being manufactured by Concrete Utilities and installed in Liverpool in 1932). The style of the bulky column, and the art-deco bracket, is an excellent example of these early concrete columns. Originally the surface would have been polished to a smooth finish, but the weathering of the last 60 years has reduced the surface back to the original, rough concrete mix.
Secondly, the large copper and brass lanterns were fitted with specialised refractor rings, which directed the light flux out towards the centre of the street, rather than along the streetâ€™s axis. Therefore to create a uniformly illuminated road surface, the lanterns had to be clustered closer together than the normal spacing; hence the requirement for a double bracket, arranged in-line with the roadâ€™s axis.
The lanterns were fitted with 1500W GLS lamps (which is a normal tungsten bulb). Additionally, the panes of the lantern were made of rimpled glass to diffuse the light and reduce glare from this intense point source.
Each complete lighting unit weighed 2 tons.
Iâ€™ve not been able to identify the manufacturers of either the columns or lanterns, but would suggest Concrete Utilities for the former, and perhaps BLEECO for the later.
When erected and completed in 1938, it was regarded as the best street lighting system in Ireland. By 1951, it was still of suitable merit that Waldram was singing its praises, dedicating a section of his book to this particular scheme.
Only subtle alterations were made during its lifetime. In 1963, the lanterns were converted to 700W high pressure mercury bulbs which gave off a more bluish-white light. Discharge lighting being far more effective than tungsten, it saved the Dublin authorities Â£10 per lantern per year, although there was a slight decrease in the installationâ€™s efficiency. (This was due to the refractors being designed for the point source of a tungsten bulb and not the vertical linear source of a mercury discharge bulb).
At some point in the mid 1960s, the lighting deemed inadequate along the centre of the carriageway, and post-top GEC lanterns were erected along the centre of the street to boost the lighting.
The death knell occurred in 1972 when the entire installation was obsoleted. The lighting around the city had been upgraded to modern standards, and the 1930s technology of the main streets was looking very dim in comparison. Dublinâ€™s lighting engineers visited Edinburgh to view the new wall-mounted lighting on Princess Street, and influenced by its clean, uncluttered design, decided on a similar, sterile design for Oâ€™Connell street. So the Oâ€™Connell concrete columns were ripped up in 1972, replaced by wall mounted GEC lanterns which burned pairs of high-pressure sodium lanterns.
In general, the early designed concrete columns and brackets have survived the longest, largely down to their sheer bulk, quality manufacturing and careful installation. By the 1940s and 1950s, spinning and prestressing of concrete columns allowed the manufacturers to build slender and thin columns. Coupled with sloppy installation by local authorities who skimped on sealing joints, many columns and brackets now show signs of water ingress i.e. cracking, spalling, and in some cases, collapse.
For this reason, concrete column manufacture for street lighting ceased in the early 1990s, and local authorities in the UK are currently embarking on schemes to remove as many of them as quickly as possible.
So, itâ€™s a small miracle that some of the old 1938 Dublin columns still exist!
Unfortunately, it looks like the remaining brackets are succumbing to cracking and spalling. This would account for the sellophane wrapped around some of the brackets and columns; theyâ€™re literally starting to fall apart. This does not bode well, as I donâ€™t know of any concrete column which has been repaired. I expect theyâ€™ll be declared dangerous and eventually removed.
A trip to the park was illuminating (ha!) because it revealed part of Dublinâ€™s street lighting heritage. Many of the brackets and lanterns in the park were manufactured in the 1930s through to the 1950s by British Thompson Houston (BTH) and the Brighton Lighting And Electrical Engineering Company (BLEECO). Iâ€™ve taken several pictures of the street lights and and identified several examples on my website:
I hope the above was of interest!
All the best,