HomeMy WebLinkAboutPermit Correspondence 1992-11-3
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Date:
November 3, 1992
To:
Don Moore - City of Springfield
From:
Cindy Brown ~.JJ ~
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Subject:
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DEPARTMENT OF
ENERGY
Charles Miller calculated wall and ceiling U.values for steel framing
Below are the U-values as calculated using Chapter 22 of the American Society of Heating
Refrigeration and Air Conditioning Engineers (ASHRAE) Handbook of Fundamentals 1989.
Wall:
Furring
R-value
Stud Header
R-value R-value
.25 .25
.81 .81
.62 .62
.60 .84
6.29 1.36
.45 .45
.68 .68
9.70 5.01
.103 .200
.07 .0212
.007 .004
.25
.81
.62
.84
.45
,68
3.65
.274
.0288
.008
Cavity
R-value
,25
.81
.62
32.12
,45
.68
34.93
,029
.88
.025
,008 + .007 + .004 + .025 = .044 overall U-value
Description
Outside Air 7.5 MPH
3/4" LP Lap Siding
1/2" sheathing
Steel stud & furring to stud
intersection
insulation
1/2" sheetrock
inside air
Total R-value
Total U-value
Area Weighing
Corrected U-value
Barbara Roberts
Governor
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625 Marion Street NE
Salem, OR 97310
(503) 378-4040
FAX (503) 373-7806
TOO (503) 378.4040
Toll Free 1.800-221-8035
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Don Moore - City of Springfield
November 3, 1992
Page 2
Ceiling:
Cavity Truss
R-value R-value
.61 .61
.40
49 38.28
.45 .45
.61 .61
50.67 40.35
.02 .025
.898 .07
.017 .001
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Web/truss
R-value
Void
R-value
Description
.61
1.82
Attic Air
Steel truss
lIisulation
1/2" sheetrock
inside air
.61
.45
.61
.45
.61
3.49
.29
.03
.008
Total R-value
Total U-value
Area Weighing
Corrected U-value
1.67
.60
.002
.001
.017 + .001 + .008 + .001 = .027 overall U-value
.'. ~= 31.of
Since Mr. Millers ceiling system incorporates Advanced framing (raised heel truss) and R-49
insulation. The table 53-P base path one requires R-38 insulation in a standard framed ceiling which
has a calculated U-value of .027 which is equivalent to Mr. Millers ceiling system. The table 53-P
Prescriptive base path one requires R-21 insulation installed in standard framing which has a U-value
of .060. Mr. Millers wall system uses advanced framing and he is installing a blown in blanket
insulation system which gives him a cavity R-value of 32.12, which calculates out to a .044 U-value.
The proposed home as submitted had a standard slab floor which Mr. Miller indicated installing R-15
rigid perimeter insulation, U-.40 windows, U-.54 entry door, U-.20 other door, R-8 ducts and no
skylights.
All of the above U-values meet the requirements of base path one and therefore the house qualifies
for the Table 53-P Prescriptive Path 1 1992 Oregon Energy Code Requirements.
As I indicated earlier, any additional homes that vary ll.Llill from the above system would require
calculations to prove compliance (eg. a steel framed floor system).
Please contact me if you have any additional questions.