University of Southern California
Prof. Schiler
School of Architecture
Spring 2005
Arch 315: Design of the Luminous and Sonic Environment
Homework Assignment #2
1.)
Given: the illumination on a horizontal plane outside a room is 1200 lumens/ft
2
(fc), and
the DF for the rear corner of the room is 2%:
a.)
is the DF enough (under the guidelines) for a drafting station?
No.
The guidelines indicate a DF of 6 for drafting.
b.)
what would be the actual footcandle level at that spot at that time?
1200 fc * .02 = 24 fc (or lumens/square foot)
2.)
If you wanted to provide enough light for a 40,000 ft
2
warehouse using overhead
horizontal skylights, how many skylights of what size would you need?
Find the suggested daylight factor (DF) for a warehouse which relies on overhead
horizontal glazing in skylights.
From the table, the suggested DF is 1.5( %).
The formula for the required area of glazing for overhead horizontal skylights is:
A
g
= DF x A
f
/ 0.5 T
g
= 0.015 x 40000 ft
2
/ 0.5 (.62) = 1935 ft
2
≈
2000 ft
2
If we use 2 x 2 skylights, they would be 4 ft
2
each.
That would require (2000 ft
2
of
skylight) / 4 ft
2
per skylight = 500 skylights.
If we use 2 x 4 skylights, they would be 8 ft2 each.
That would require (2000 ft
2
of
skylight) / 8 ft
2
per skylight = 250 skylights
If we use 4 x 4 skylights, they would be 16 ft
2
each.
That would require (2000 ft
2
of
skylight) / 16 ft
2
per skylight = 125 skylights.
That’s beginning to get pretty far apart.
If
the ceiling weren’t high enough, there would be dark areas between skylights.
3.)
If you wanted to provide enough light for an office space that was 40 ft x 40 ft and 8 ft
high, lit entirely from one side, how big would the window have to be?
(Show your
assumptions and your work.)
Find the suggested daylight factor (DF) for an office which relies on side glazing to
replace electric lighting, whenever possible.
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 Spring '06
 Schiler
 Architecture, Imperial units, Horizontal plane, DF x Af

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