Monthly Archives: December 2024

Lux Contour Map & Light Spill Assessment – Chelsea, London

Lux Contour Map & Light Spill Assessment – Chelsea, London

Earlier this month we were commissioned to write a light spill assessment for a residential project in Chelsea, London the project involved modeling a site that was undergoing refurbishment & redevelopment, and observing the light spill given a specific set of internal and external light fittings.

Image showing a 3D model of a building and the lights spill which is emanating from the glazed facade the spill is shown as contours labeled with Lux values and false Color has been applied to the contour lines in shades of pink purple and blue to share the intensity of the lights spill

Lux Contour Modelling

We were able to model a three-story building with extensive glazing overlooking a rear courtyard the internal lighting intensity was set an acceptable Lux level and the glazing apertures were accurately placed so as to show spill into the rear Courtyard they’re also some windows from Neighboring properties overlooking Courtyard.

We also created simple building layouts for these neighbouring buildings and examined the lights bill into the bedrooms assumed of these Neighboring properties we’re able to show with the model that the lights belt into the bedrooms was below one Lux which is considered a criteria for sleep disturbance.

Lighting design has advanced considerably in the last decade, and the variety of beam shapes available are mind boggling, with an asymmetric beam shape you can place fittings close to a boundary, and limit light spill into neighbouring property.

Some manufactures publish very detailed data for their light fitting which enable us to model them accurately. If you are looking for light fittings of a specific type then please ask us, as we have seen 100’s of types over the years, although for ecological lighting design we do have our favourites.

If you need a slight spill assessment or a lux contour plan (or both!) then please contact us for no-obligation chat, and fixed price quotation.

 

Incorrect Flood Zone 3b on Flood Mapping

Incorrect Flood Zone 3b on Flood Mapping

This is about as niche as it gets . . . . but here we go!

We have recently seen a couple of examples where Cornwall Council’s flood mapping (which is different to flood map for planning) gives some very strange results for Flood Zone 3b.

How Flood Zones Normally Appear

Perhaps the most familiar flood mapping for those “in the trade” is the flood map for planning. Typically we see the darker blue (more often flooding)  Flood Zone 3, fringed with lighter blue (less often flooding) Flood Zone 2.

screen shot from flood map for planning

Screen shot from flood map for planning.

In flood mapping it is always the cases that a “more often” flood outline (shaded area) never go outside of the “less often” flood outline. Look:

Flood Zones from Some Older Mapping

In the above slide the dark blue areas do not extend beyond the light blue areas. They can extend up to the edge, but not beyond.

Flood Zone 3b on Cornwall Council Flood Mapping

So when we first saw the mapping from Cornwall Councils’ own mapping service below we knew something was wrong with it. Apart from the strange colour scheme, you can see Flood Zone 3b Extends well beyond Flood Zones 2 and Flood Zone 3a.

So there is something wrong with the modelling of Flood Zone 3b at this site.

Incorrect Flood Zone 3b – Cornwall Mapping

The image below shows the beginning of our investigations in to the error. We made a detailed study of elevations in the vicinity for starters and then wrote a report to explain why the site in this instance should not be included in Flood Zone 3b.

Detailed Contour Zones on Google Satellite Images

And we are happy to say that the argument we politely put forward worked well, and the permissions was granted.

If you have issues with a site that appears to be included in FLood Zone 3b, when maybe you think it shouldn’t be then please do contact us and we will be glad to help. We can deal with this issue as part of a flood risk assessment or as a bolt on.

We have seen strange behaviour like this in Cornwall Council’s flood mapping, and also in Bristol City Council’s Flood Mapping.