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Commercial Energy practice question

F

fiddler

Bronze Member
Joined
Jul 6, 2011
Messages
37
Exterior lighting planned for a commercial building

Parking lot 20,000 sq. ft

8' wide walks 300 linear ft.

main entries 2 at 6' wide

atm 1 location

considering both nontradable and tradable services what is the total lighting power density for this building.

I can not for the life of me come up with the correct answer for this question.

P.S. the question is out of the 2009 study companion. They give you the answer nad the code ref. but do not explain how they got the answer.

If any one could help it would be appreciated.
 
2009 IECC Table 505.6.2



Parking lot 20,000 sq. ft / 0.15 W/sq. ft. x 20000 = 3000 watts (trade)

8' wide walks 300 linear ft. / 1.0 watts/lin. ft. x 300 = 300 watts (trade)

main entries 2 at 6' wide / 30 watts/lin ft door width = 12 x 30 = 360 (trade)

atm 1 location / 270 watts for 1 location (nontrade)

3930 watts.

That's what I come up with.
 
fiddler said:
Exterior lighting planned for a commercial buildingParking lot 20,000 sq. ft

8' wide walks 300 linear ft.

main entries 2 at 6' wide

atm 1 location

considering both nontradable and tradable services what is the total lighting power density for this building.

I can not for the life of me come up with the correct answer for this question.

P.S. the question is out of the 2009 study companion. They give you the answer nad the code ref. but do not explain how they got the answer.

If any one could help it would be appreciated.
Click to expand...
Doesn't the zone also need to be known for the equation? Both 3 and 4 could be commercial and have different watts per square foot.
 
North Star The question is as it was stated in the book. You got the correct answer but whre did you get .15 for parking areas?
 
fiddler said:
North Star The question is as it was stated in the book. You got the correct answer but whre did you get .15 for parking areas?
Click to expand...
I know this is an old thread- I'm picking up some of my easier certs and this question has been making me crazy.

Tjacobs, you didn't include the 1300 Watts for the base site allowance- Why not?

and my 2009 IECC shows .13W/sq ft for parking areas in a zone 4, not .15.

therefore...

Base site allowance 1300w

Parking lot 20,000 sq. ft / 0.13 W/sq. ft. x 20000 = 2600 watts (trade)

8' wide walks 300 linear ft. / 1.0 watts/lin. ft. x 300 = 300 watts (trade)

main entries 2 at 6' wide / 30 watts/lin ft door width = 12 x 30 = 360 (trade)

atm 1 location / 270 watts for 1 location (nontrade)

for a grand total of 4830w. This is not one of the available answers.

Apparently, I'm missing somehting. Can anyone help me out?
 
-sigh- just realized what I am missing... I have the 6th printing of the 2009 IECC, and I am missing Table 505.6.2.

I swear I spent 2 hours on that stupid question because I have a bad printing... well that was pretty frustrating, but at least I got it.

THANKS TO THE BUILDING CODE FORUM!!
 
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