Sandy's Garden ... Let There Be (A Little) Light

I have mentioned in a previous column that the street where I live has enjoyed having all the old concrete lamp posts replaced with shiny new metal columns, all rather taller than the posts which they replace.

By Sandy Simpson
Tuesday, 23rd February 2021, 3:15 pm

There is one just outside my house and, although it is not actually in my garden, it does come pretty close.

The back of the column is exactly 180mm … say 7 inches in old money … from the edge of the artificial grass which forms my front lawn; and a little of the light shining from the new luminaire reaches more of my garden than the glow from the old lamp did.

It has also changed the night-time lighting in the upstairs front bedroom of our house, the vivid orange of the sodium lamp replaced by what I fancy is termed the ‘warm white’ glow of the light emitting diodes (LEDs).

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Falkirk Herald gardening guru Sandy Simpson

The fact that the new pole is a little further away from the bedroom window is counterbalanced by the pole’s extra height when it comes to light distribution and, despite the street lighting engineer’s intentions, I am pretty certain that the amount of intrusive light is no less than it used to be.

More of our garden is definitely … albeit unintentionally … lit by the repositioned street light for, though very little … if any … light escapes upwards from the luminaire, the downward-directed light is meant to expand across an area of land spreading outward from the column; and rather more of our garden now comes within the boundaries of its area of illumination.

The novelty of these developments set me to wonder about several matters.

‘Street lighting column heights in the UK are generally standard heights when adopted by the councils and would either be 5, 6, 8, 10 or 12m heights. As a general rule, typical heights used in roads could be: Residential Road – 5 and 6m mounting height; Residential distributor/primary road – 8m mounting height; and Trunk Road – 10m mounting height.’

That’s taken from the website of MMA Lighting Consultancy.

By a rough calculation, I reckon the old concrete posts were 7m and that the new metal columns support their luminaires 8m above the pavement, which surprises me, for I live in what is definitely a ‘residential street.’

Turning to the positioning of the columns, the recommendation for a residential street is that they should be close to the edge of the footway further from the road.

That’s where our new poles are and where the old poles were. And, unsurprisingly, the new poles are identical in number to the old and are all close to the former poles’ locations – in other words, the spacing is very similar.

From the website ‘engineeringdiscoveries’, I learn that, ‘The spacing between light poles should be 2.5–3 times the height of the pole. The density, speed of travel and the type of light source along a corridor will also determine the ideal height and spacing.’ As the number of houses in our cul-de-sac has not increased since it was built,

I think I’ll inspect those parts of my garden which nowanights catch a glimmer of intrusive light … or perhaps I’ll just stay in, for there’s a gey snell wind out there!