Hi,
I am investigating the priority schools criteria for daylighting.
I am struggling to get a room with single sided glazing to pass.
The examples from the EFA all have borrowed light to the back of the room. Has anyone managed to get a room to comply without this?
Ross
Priority Schools Daylight Autonomy
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RossThompson87
- VE Professor
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- Joined: Mon Feb 13, 2012 8:56 am
Re: Priority Schools Daylight Autonomy
I was looking at the same thing last week. My conclusion was that it's going to be almost impossible to get a normal depth, single sided classroom to pass. Even with borrowed light I was struggling to pass the UDI target, usually because the rooms spent too much time in the 'above 2000 lux' range. but reducing the glazing then caused the DA to not meet the minimum 50%.
Out of interest, how were you calculating your UDI value? I set the range test to report results between 100 and 2000 lux, pulled up the table of results, imported to Excel, and then averaged the 'UDI 100 to 2000 lux' column. I *think* that gave me what I was looking for but it's an incredibly cumbersome way of getting it.
John.
Out of interest, how were you calculating your UDI value? I set the range test to report results between 100 and 2000 lux, pulled up the table of results, imported to Excel, and then averaged the 'UDI 100 to 2000 lux' column. I *think* that gave me what I was looking for but it's an incredibly cumbersome way of getting it.
John.
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RossThompson87
- VE Professor
- Posts: 202
- Joined: Mon Feb 13, 2012 8:56 am
Re: Priority Schools Daylight Autonomy
Hi John,
I did eventually get a single sided typical classroom to pass the PSBP criteria without borrowed light. But I did have the same issue of excessive light near the windows.
I eventually managed to get in contact with someone at the EFA who confirmed the goal posts had been moved to 3000 lux to make life easier. This is because the 2000 lux was based on reading on old curved CRT screen and modern screens are much better.
So you now only have to stay in the 100 - 3000 lux range. This got me a bit closer to passing.
I then managed to get over the line with a venetian blind or a translucent roller blind to 'scatter' the light. As the light still gets in, DA doesn't suffer too badly.
I actually ended up moving away from IES for my calcs. But I was averaging the readings for each point in excel.
I also got clarification that some points can be less than 80% of the time in range as long as the average for the workplane is ok.
The calculation settings also play a big effect. I'm not sure what IES assumes but the number of ambient bounces is very important as lots of bounces are needed for light to reach the back of a room.
I found it a frustrating route but the EFA were really helpful and once you know a few tricks life seemed to get much easier and I was getting rooms to pass after one or two attempts.
Ross
I did eventually get a single sided typical classroom to pass the PSBP criteria without borrowed light. But I did have the same issue of excessive light near the windows.
I eventually managed to get in contact with someone at the EFA who confirmed the goal posts had been moved to 3000 lux to make life easier. This is because the 2000 lux was based on reading on old curved CRT screen and modern screens are much better.
So you now only have to stay in the 100 - 3000 lux range. This got me a bit closer to passing.
I then managed to get over the line with a venetian blind or a translucent roller blind to 'scatter' the light. As the light still gets in, DA doesn't suffer too badly.
I actually ended up moving away from IES for my calcs. But I was averaging the readings for each point in excel.
I also got clarification that some points can be less than 80% of the time in range as long as the average for the workplane is ok.
The calculation settings also play a big effect. I'm not sure what IES assumes but the number of ambient bounces is very important as lots of bounces are needed for light to reach the back of a room.
I found it a frustrating route but the EFA were really helpful and once you know a few tricks life seemed to get much easier and I was getting rooms to pass after one or two attempts.
Ross
Re: Priority Schools Daylight Autonomy
When doing the normal Radiance calculations within IES you can change the settings for number of bounces etc. but I don't think this is an option at the moment in the dynamic daylight calculation options. Something to be added in a future development perhaps.
John.
John.
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RossThompson87
- VE Professor
- Posts: 202
- Joined: Mon Feb 13, 2012 8:56 am
Re: Priority Schools Daylight Autonomy
Hi,
No I am pretty sure there is no option for dynamically changing the blinds / geometry.
I got some rooms to pass, just by leaving a venetian blind in the same fixed open position all year.
Alternatively leaving a translucent roller blind down all the time also worked.
Ross
No I am pretty sure there is no option for dynamically changing the blinds / geometry.
I got some rooms to pass, just by leaving a venetian blind in the same fixed open position all year.
Alternatively leaving a translucent roller blind down all the time also worked.
Ross
Re: Priority Schools Daylight Autonomy
Hi,
Any chance either of you know if the issue regarding automed blinds has been addressed as yet? Blinds on the south elevations seems a standard measure now to be able to meet the UDI target, but it doesn't appear to be an option.
Also need to ask about increasing the number of bounces but i will do that in a separate thread.
Thanks
Any chance either of you know if the issue regarding automed blinds has been addressed as yet? Blinds on the south elevations seems a standard measure now to be able to meet the UDI target, but it doesn't appear to be an option.
Also need to ask about increasing the number of bounces but i will do that in a separate thread.
Thanks