Skylights and LED lighting

[Henchalwoog]

So the IECC allows for required skylights to be deleted per exceptions - one of which is a lighting power density of under .5 watts per sq ft...the 2012 IECC lists a warehouse LPD of .6 watts per sq ft which is over the exception...a designer has provided a warehouse design that would require skylights due to the size and height with a LED system that is under that figure...is the LPD in the code table (.6) the threshold that you use to require a skylight or is it the number provided by the designer which is lower and meets the exception?

 

[Yankee Chronicler]

The 2012 IECC? What jurisdiction is this?

 

[Henchalwoog]

The 2012 IECC? What jurisdiction is this?

The State of Iowa has adopted this version statewide and has not updated it

 

[steveray]

The State of Iowa has adopted this version statewide and has not updated it

Go Iowa!

 

[Gregg Harris]

So the IECC allows for required skylights to be deleted per exceptions - one of which is a lighting power density of under .5 watts per sq ft...the 2012 IECC lists a warehouse LPD of .6 watts per sq ft which is over the exception...a designer has provided a warehouse design that would require skylights due to the size and height with a LED system that is under that figure...is the LPD in the code table (.6) the threshold that you use to require a skylight or is it the number provided by the designer which is lower and meets the exception?

Look under C 402.3.1

 

[Henchalwoog]

Go Iowa!

Are you "BC" Iowa (before Caitlin)? lol

 

[Henchalwoog]

Look under C 402.3.1

Well after sleeping on it and reconsidering I have decided that the lighting design values are valid and can be used to exclude the skylights - energy conserved is energy conserved right? Thanks for the input.

 

[Yankee Chronicler]

Look under C 402.3.1

I would have said 402.3.2, but it can't hurt to read both.

 

[Yankee Chronicler]

So the IECC allows for required skylights to be deleted per exceptions - one of which is a lighting power density of under .5 watts per sq ft...the 2012 IECC lists a warehouse LPD of .6 watts per sq ft which is over the exception...a designer has provided a warehouse design that would require skylights due to the size and height with a LED system that is under that figure...is the LPD in the code table (.6) the threshold that you use to require a skylight or is it the number provided by the designer which is lower and meets the exception?

Can we assume the exception to which you refer is Exception 2 to 402.3.2?

If so, the language of the exception is pretty straightforward.

Exception: Skylights above daylight zones of enclosed
spaces are not required in:
1. Buildings in climate zones 6 through 8.
2. Spaces where the designed general lighting power
densities are less than 0.5 W/ft2 (5.4 W/m2).

What's the overall Lighting Power Density of the design submitted?

 

[Henchalwoog]

Can we assume the exception to which you refer is Exception 2 to 402.3.2?

If so, the language of the exception is pretty straightforward.



What's the overall Lighting Power Density of the design submitted?

It is below the threshold however my original question was if the listed LPD values in the IECC (.6 listed for warehouse) was the value applied to the skylights (.6 design value exceeds .5 so skylights required regardless in any warehouse that meets the height and area requirements)
I see now that this is not the case