Washington Administrative Code › Title 51 - Enterprise Services, Department of (Building Code Council) › Chapter 51-11C - State Building Code adoption and amendment of the 2021 edition of the International Energy Conservation Code, Commercial › Section 51-11C-402121 - Table C402.1.3-Opaque thermal envelope assembly R-value requirements

Current through Register Vol. 24-14, July 15, 2024
Table C402.1.3 Opaque Thermal Envelope Insulation
				Component Minimum Requirements,
R-value
Methoda,j
CLIMATE ZONE
5 AND MARINE 4
All Other
Group R
Roofs
Insulation entirely above deck
R-38ci
R-38ci
Metal buildingsb
R-25 + R-22 LS
R-25 + R-22 LS
Attic and other
R-49
R-49
Walls, Above
						  Gradei
Massh
R-9.5ci
R-13.3ci
Mass transfer deck slab
						  edgeg
Metal buildings
R-13 + R-14ci
R-13 + R-14ci
Steel framed
R-13 + R-10ci
R-19 + R-8.5ci
Wood framed and other
R-13 + R-7.5ci std or R-20 + R-3.8ci std
R-13 + R-7.5ci std or R-20 + R-3.8ci std or R-25
						  std
Walls, Below Grade
Below-grade walld,h
Same as above grade
Same as above grade
Floors
Massf
R-30ci
R-30ci
Joist/framing
R-30e
R-30e
Slab-on-Grade Floors
Unheated slabs
R-10 for 24" below
R-10 for 24" below
Heated slabs
R-10 perimeter & under entire slab
R-10 perimeter & under entire slab
For SI: 1 inch = 25.4 mm. ci = Continuous insulation. NR = No
				requirement.
LS = Liner system-A continuous membrane installed below the
				purlins and uninterrupted by framing members. Uncompressed, unfaced insulation
				rests on top of the membrane between the purlins.
a Assembly descriptions can be found in
				Chapter 2 and Appendix A.
b Where using
R
-value compliance method, a thermal spacer block with minimum
				thickness of 1/2-inch and minimum
R
-value of R-3.5 shall be
				provided, otherwise use the
U
-factor compliance method in
				Table C402.1.4.
c Exception: Integral insulated
				concrete block walls complying with ASTM C90 with all cores filled and meeting
				both of the following:
1. At least 50 percent of cores must be filled with vermiculite
				or equivalent fill insulation; and
2. The building thermal envelope encloses one or more of the
				following uses: Warehouse (storage and retail), gymnasium, auditorium, church
				chapel, arena, kennel, manufacturing plant, indoor swimming pool, pump station,
				water and waste water treatment facility, storage facility, storage area, motor
				vehicle service facility. Where additional uses not listed (such as office,
				retail, etc.) are contained within the building, the exterior walls that
				enclose these areas may not utilize this exception and must comply with the
				appropriate mass wall
R
-value from Table
				C402.1.3/
U
-factor from Table C402.1.4.
d Where heated slabs are below
				grade, they shall comply with the insulation requirements for heated
				slabs.
e Steel floor joist systems shall be
				insulated to R-38 + R-10ci.
f "Mass floors" shall include floors
				weighing not less than:
1. 35 pounds per square foot of floor surface area; or
2. 25 pounds per square foot of floor surface area where the
				material weight is not more than 120 pounds per cubic foot.
g Component performance in accordance
				with Section C402.1.5 shall be required for buildings with a mass transfer deck
				slab.
he floors are included in the
				above-grade mass wall category and therefore must be insulated as above-grade
				mass walls unless they meet the definition of Mass Transfer Deck Slab Edge. The
				area of the peripheral edges of concrete floors shall be defined as the
				thickness of the slab multiplied by the perimeter length of the edge condition.
				See Table A103.3.7.2 for typical default
U
-factors for
				above-grade slab edges and footnote 
				c for typical conditions of above-grade
				slab edges.
i Where the total area of
				through-wall mechanical equipment is greater than 1 percent of the opaque
above-grade wall area
, use of the
R
-value
				method is not permitted. See Section C402.1.4.3.
j For roof, wall or floor assemblies
				where the proposed assembly would not be
continuous
				insulation
, alternate nominal
R
-value compliance
				options for assemblies with isolated metal fasteners that penetrate otherwise
continuous insulation
are as shown in columns B and C of Table
				C402.1.3(i):
Table C402.1.3(i) Continuous Insulation
				Equivalents
Column A
Column B
Column C
Assemblies with continuous insulation (see
						  definition)
Alternate option for assemblies with metal
						  penetrations, greater than 0.04% but less than 0.08%
Alternate option for assemblies with metal
						  penetrations, greater than or equal to 0.08% but less than 0.12%
R-9.5ci
R-11.9ci
R-13ci
R-11.4ci
R-14.3ci
R-15.7ci
R-13.3ci
R-16.6ci
R-18.3ci
R-15.2ci
R-19ci
R-21ci
R-30ci
R-38ci
R-42ci
R-38ci
R-48ci
R-53ci
R-13 + R-7.5ci
R-13 + R-9.4ci
R-13 + R-10.3ci
R-13 + R-10ci
R-13 + R-12.5ci
R-13 + R-13.8ci
R-13 + R-12.5ci
R-13 + R-15.6ci
R-13 + R-17.2ci
R-13 + R-13ci
R-13 + R-16.3ci
R-13 + R-17.9ci
R-19 + R-8.5ci
R-19 + R-10.6ci
R-19 + R-11.7ci
R-19 + R-14ci
R-19 + R-17.5ci
R-19 + R-19.2ci
R-19 + R-16ci
R-19 + R-20ci
R-19 + R-22ci
R-20 + R-3.8ci
R-20 + R-4.8ci
R-20 + R-5.3ci
R-21 + R-5ci
R-21 + R-6.3ci
R-21 + R-6.9ci
Notes for Table C402.1.3(j)
These alternate nominal
R
-value compliance
				options are allowed for projects complying with all of the following:
1a. The ratio of the cross-sectional area, as
			 measured in the plane of the surface, of metal penetrations of otherwise
			 continuous insulation to the opaque surface area of the assembly is greater
			 than 0.0004 (0.04%), but less than 0.0008 (0.08%), for use of Column B
			 equivalents, and greater than or equal to 0.008 (0.08%), but less than 0.0012
			 (0.12%), for use of Column C equivalents.
1b. Where all metal penetrations are
			 stainless steel, Column B is permitted to be used for penetrations greater than
			 0.12%, but less than 0.24% of opaque surface area, and Column C is permitted to
			 be used for penetrations greater than or equal to 0.24%, but less than 0.48% of
			 opaque surface area.
2. The metal
			 penetrations of otherwise continuous insulation are isolated or discontinuous
			 (e.g., brick ties or other discontinuous metal attachments, offset brackets
			 supporting shelf angles that allow insulation to go between the shelf angle and
			 the primary portions of the wall structure). No continuous metal elements
			 (e.g., metal studs, z-girts, z-channels, shelf angles) penetrate the otherwise
			 continuous portion of the insulation.
3. Building permit drawings shall contain
			 details showing the locations and dimensions of all the metal penetrations
			 (e.g., brick ties or other discontinuous metal attachments, offset brackets,
			 etc.) of otherwise continuous insulation. In addition, calculations shall be
			 provided showing the ratio of the cross-sectional area of metal penetrations of
			 otherwise continuous insulation to the overall opaque wall area.
For other cases where the proposed assembly is not continuous
				insulation, see Section C402.1.4 for determination of
U
-factors for assemblies that include metal other than screws
				and nails.
Statutory Authority:
				  RCW
				    19.27A.020,
				  19.27A.025 and
				  chapters
				  19.27 and
				  34.05 RCW. 13-04-056, §
				  51-11C-402121, filed 2/1/13, effective
				  7/1/13.