Wash. Admin. Code § 51-11C-61014

Current through Register Vol. 24-20, October 15, 2024
Section 51-11C-61014 - Section A101.4 - Compression of insulation

A101.4 Compression of insulation. Insulation which is compressed shall be rated in accordance with Table A101.4 or reduction in value may be calculated in accordance with the procedures in the ASHRAE Fundamentals Handbook.

Table A101.4 R-value of Fiberglass Batts Compressed Within Various Depth Cavities

Insulation R-Values at Standard Thickness

Rated R-Value

82

71

60

49

38

30

22

21

19

15

13

11

Standard Thickness, Inches

26.0

22.5

19.0

15.5

12

9.5

6.5

5.5

6

3.5

3.5

3.5

Nominal Lumber Sizes, Inches

Actual Depth of Cavity, Inches

Insulation R-Values when Installed in a Confined Cavity

Truss

26.0

82

--

--

--

--

--

--

--

--

--

--

--

Truss

22.5

--

71

--

--

--

--

--

--

--

--

--

--

Truss

19.0

--

--

60

--

--

--

--

--

--

--

--

--

Truss

15.5

--

--

--

49

--

--

--

--

--

--

--

--

Truss

12.0

--

--

--

--

38

--

--

--

--

--

--

--

2 x 12

11.25

--

--

--

--

37

--

--

--

--

--

--

--

2 x 10

9.25

--

--

--

--

32

30

--

--

--

--

--

--

2 x 8

7.25

--

--

--

--

27

26

22

21

19

--

--

--

2 x 6

5.5

--

--

--

--

--

21

20

21

18

--

--

--

2 x 4

3.5

--

--

--

--

--

--

14

--

13

15

13

11

2.5

--

--

--

--

--

--

--

--

--

--

9.8

--

1.5

--

--

--

--

--

--

--

--

--

--

6.3

6.0

Wash. Admin. Code § 51-11C-61014

Statutory Authority: RCW 19.27A.020, 19.27A.025 and chapters 19.27 and 34.05 RCW. 13-04-056, § 51-11C-61014, filed 2/1/13, effective 7/1/13.