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Topic Title: 0.5m boundary on lighting software packages on corridors
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Created On: 05 October 2015 09:58 AM
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 05 October 2015 09:58 AM
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Matt01

Posts: 216
Joined: 25 July 2008

I've been reviewing some lighting calculations that have been undertaken for a scheme we're on to which the designer has left the 0.5m boundary on every space. For narrow corridors this practically leaves nothing left to measure on the calculation and seems a bit of a cheat to achieve a higher lighting level. I'll accept it in large open spaces but in areas such as WC's and corridors i'm reluctant too. Hes quotes clause 2.1.3.4 out of the SLL code of lighting 2012 but reading this again i think this relates more to office areas.

Can someone tell me is there a clause somewhere that identifies for these types of spaces you need to calculate the full space? I know on the emergency side you need to but in regards to general lighting.

The corridor in question is 1500mm wide so by adding this 0.5m boundary you are only calculating a 1/3 of the space.
 05 October 2015 10:25 AM
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pww235

Posts: 199
Joined: 03 April 2014

It could be argued that within the corridor the whole area is the 'task area' therefore the 0.5m boundary should be omitted.

Or, if they have aimed for the target Eav of 100lux which the SLL Code gives for corridors and general circulation spaces then the 0.5m boundary should also be lit to 100lux by virtue of Table 2.1.

You may find there is little difference in the Eav if they were to include this boundary area since the corridor is only 1.5m wide, unless they've used luminaires with a narrow beam angle or it is a particularly low ceiling.
 05 October 2015 10:43 AM
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mawry

Posts: 324
Joined: 26 April 2004

What software have they used?

On dialux in the standard output sheet. The floor level calculation output is for the full width of the corridor. The 0.5 boundary is only applied to the reference workplane, which unless the user has altered it is defaulted to 0.75m.
 05 October 2015 11:23 AM
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Matt01

Posts: 216
Joined: 25 July 2008

They have used Relux, the scheme is for a university so LG5 applies. The average illuminance for the corridor space is 108 Lux but then they are disregarding a 1/3 of the space. the fittings they are using are linear LED with a default MF of 0.8.
 05 October 2015 01:50 PM
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pww235

Posts: 199
Joined: 03 April 2014

There's nothing I know of that says they can't use the 0.5m boundary in those spaces, other than logically thinking about what is the actual task area. In those types of spaces, to me it makes more sense to assume the floor as the workplane which negates the issue of boundary zone in the calc as the software measures the full floor as a room surface.
 06 October 2015 02:23 PM
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smithy2588

Posts: 1
Joined: 27 May 2015

2.1.3.4 relates to the immediate surrounding area lighting level, which is entirely different from putting a 0.5M boundary on a lighting calculation.

The immediate surrounding area lighting calc is only considered when the primary area being illuminated is a task area (i.e. where someone is working). So in your case this does not apply as it is a corridor. The working plane is what is required to be calculated, which for a corridor is 0M (floor level) refer to LG7 table 2.5.

I'd request the calc is re-run incorporating the above with a sensible boundary added (0.150mm-0.250mm). It's also a good idea to ask for the colour render output from the calculation as this should give an accurate illustration of the lighting levels.
 06 October 2015 04:26 PM
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pww235

Posts: 199
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Agreed Smithy.
 06 October 2015 09:11 PM
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TeesdaleSpark

Posts: 690
Joined: 12 November 2004

There is a useful guide to EN 12464-1 available here: http://en.licht.de/en/

It advises:

"d. Corridor
In corridors, the entire area of the room in which traffic
flows occur is regarded as the reference surface. For
corridors up to 2.5 m wide, it is recommended - in line
with DIN EN 1838 - that a central strip on the floor at
least 1.0 m wide should be regarded as the reference
surface and the rest of the space to the walls treated as
surrounding area. In wider corridors, the central strip
constituting the reference surface should be adjusted
accordingly. Uniformity on the reference surface is 0.40.
Walls require vertical illuminance Ev > 50 lx and a minimum
uniformity of 0.10. Visual tasks here include doors,
door handles and signs."

BS EN 12464-1 states that "A band of 0,5 m from the walls is excluded from the calculation area except when a task area is in or extends into this border area."

However note that table 1 of BS EN 12464-1 states that the illuminance of the "surrounding area" should be the same as the task area when the task area required illuminance is <= 150 lux.
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