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C301.1 General

AMENDMENT
This section has been amended at the state or city level.
Climate zones from Table C301.1 shall be used in determining the applicable requirements from Chapter 4.


TABLE C301.1
CLIMATE ZONES, MOISTURE REGIMES, AND WARM-HUMID DESIGNATIONS BY STATE AND COUNTY


Key: A — Moist, B — Dry, C — Marine.
Absence of moisture designation indicates moisture regime is irrelevant.

WASHINGTON

5B Adams

5B Asotin

5B Benton

5B Chelan

4C Clallam

4C Clark

5B Columbia

4C Cowlitz

5B Douglas

5B Ferry

5B Franklin

5B Garfield

5B Grant

4C Grays Harbor

4C Island

4C Jefferson

4C King

4C Kitsap

5B Kittitas

5B Klickitat
4C Lewis

5B Lincoln

4C Mason

5B Okanogan

4C Pacific

5B Pend Oreille

4C Pierce

4C San Juan

4C Skagit

5B Skamania

4C Snohomish

5B Spokane

5B Stevens

4C Thurston

4C Wahkiakum

5B Walla Walla

4C Whatcom

5B Whitman

5B Yakima

C301.2 Warm Humid Counties

AMENDMENT
This section has been amended at the state or city level.

C301.3 International Climate Zones

AMENDMENT
This section has been amended at the state or city level.

C301.4 Tropical Climate Zone

AMENDMENT
This section has been amended at the state or city level.
The interior design temperatures used for heating and cooling load calculations shall be a maximum of 72°F (22°C) for heating and minimum of 75°F (24°C) for cooling.

C302.2 Exterior Design Conditions

AMENDMENT
This section has been amended at the state or city level.
The heating or cooling outdoor design temperatures shall be selected from Appendix C.
Materials, systems and equipment shall be identified in a manner that will allow a determination of compliance with the applicable provisions of this code.
An R-value identification mark shall be applied by the manufacturer to each piece of building thermal envelope insulation 12 inches (305 mm) or greater in width. Alternately, the insulation installers shall provide a certification listing the type, manufacturer and R-value of insulation installed in each element of the building thermal envelope. For blown or sprayed insulation (fiberglass and cellulose), the initial installed thickness, settled thickness, settled R-value, installed density, coverage area and number of bags installed shall be listed on the certification. For sprayed polyurethane foam (SPF) insulation, the installed thickness of the areas covered and R-value of installed thickness shall be listed on the certification. For insulated siding, the R-value shall be labeled on the product's package and shall be listed on the certification. The insulation installer shall sign, date and post the certification in a conspicuous location on the job site.

C303.1.1.1 Blown or Sprayed Roof/Ceiling Insulation

AMENDMENT
This section has been amended at the state or city level.
The thickness of blown-in or sprayed roof/ceiling insulation (fiberglass or cellulose) shall be written in inches (mm) on markers that are installed at least one for every 300 square feet (28 m2) throughout the attic space. The markers shall be affixed to the trusses or joists and marked with the minimum initial installed thickness with numbers of > CE-18 2015 Washington State Energy Code, 2nd Edition not less than 1 inch (25 mm) in height. Each marker shall face the attic access opening. Spray polyurethane foam thickness and installed R-value shall be listed on certification provided by the insulation installer.
Insulating materials shall be installed such that the manufacturer's R—value mark is readily observable upon inspection.

C303.1.3 Fenestration Product Rating

AMENDMENT
This section has been amended at the state or city level.
U-factors of fenestration products (windows, doors and skylights) shall be determined in accordance with NFRC 100.

Exception: Where required, garage door U-factors shall be determined in accordance with either NFRC 100 or ANSI/SASMA 105.

U-factors shall be determined by an accredited, independent laboratory, and labeled and certified by the manufacturer.

Products lacking such a labeled U-factor shall be assigned a default U-factor from Table C303.1.3(1), C303.1.3(2) or C303.1.3(4). The solar heat gain coefficient (SHGC) and visible transmittance (VT) of glazed fenestration products (windows, glazed doors and skylights) shall be determined in accordance with NFRC 200 by an accredited, independent laboratory, and labeled and certified by the manufacturer. Products lacking such a labeled SHGC or VT shall be assigned a default SHGC or VT from Table C303.1.3(3).

Exception: Units without NFRC ratings produced by a small business may be assigned default U-factors from Table C303.1.3(5) for vertical fenestration.


TABLE C303.1.3(1)
DEFAULT GLAZED FENESTRATION U-FACTORS


FRAME TYPE SINGLE
PANE
DOUBLE
PANE
SKYLIGHT
Metal 1.20 0.80 See Table
C303.1.3(4)
Metal with Thermal Break1 1.10 0.65
Nonmetal or Metal Clad 0.95 0.55
Glazed Block 0.60
1 Metal Thermal Break .= A metal thermal break framed window shall incorporate the following minimum design characteristics:
  1. The thermal conductivity of the thermal break material shall be not more than 3.6 Btu-in/h/ft2/°F;
  2. The thermal break material must produce a gap in the frame material of not less than 0.210 inches; and
  3. All metal framing members of the products exposed to interior and exterior air shall incorporate a thermal break meeting the criteria in a) and b) above.


TABLE C303.1.3(2)
DEFAULT DOOR U-FACTORS


See Appendix A, Section A107

TABLE C303.1.3(3)
DEFAULT GLAZED FENESTRATION SHGC AND VT
  SINGLE GLAZED DOUBLE GLAZED GLAZED
BLOCK
Clear Tinted Clear Tinted
SHGC 0.40 0.40 0.40 0.40 0.40
VT 0.6 0.3 0.6 0.3 0.6


TABLE C303.1.3(4)
DEFAULT U-FACTORS FOR SKYLIGHTS
Fenestration Type Frame Type
Aluminum
Without Thermal Break
Aluminum
With Thermal Break
Reinforced
Vinyl/
Aluminum-Clad Wood or Vinyl
Wood or Vinyl-
Clad Wood/
Vinyl without
Reinforcing
Single Glazing        
   glass U-1.58 U-1.51 U-1.40 U-1.18
   acrylic/polycarb U-1.52 U-1.45 U-1.34 U-1.11
Double Glazing        
   air U-1.05 U-0.89 U-0.84 U-0.67
   argon U-1.02 U-0.86 U-0.80 U-0.64
Double Glazing, e=0.20        
   air U-0.96 U-0.80 U-0.75 U-0.59
   argon U-0.91 U-0.75 U-0.70 U-0.54
Double Glazing, e=0.10        
   air U-0.94 U-0.79 U-0.74 U-0.58
   argon U-0.89 U-0.73 U-0.68 U-0.52
Double Glazing, e=0.05        
   air U-0.93 U-0.78 U-0.73 U-0.56
   argon U-0.87 U-0.71 U-0.66 U-0.50
Triple Glazing        
   air U-0.90 U-0.70 U-0.67 U-0.51
   argon U-0.87 U-0.69 U-0.64 U-0.48
Triple Glazing, e=0.20        
   air U-0.86 U-0.68 U-0.63 U-0.47
   argon U-0.82 U-0.63 U-0.59 U-0.43
Triple Glazing, e=0.20 on 2 surfaces        
   air U-0.82 U-0.64 U-0.60 U-0.44
   argon U-0.79 U-0.60 U-0.56 U-0.40
Triple Glazing, e=0.10 on 2 surfaces        
   air U-0.81 U-0.62 U-0.58 U-0.42
   argon U-0.77 U-0.58 U-0.54 U-0.38
Quadruple Glazing, e=0.10 on 2 surfaces        
   air U-0.78 U-0.59 U-0.55 U-0.39
   argon U-0.74 U-0.56 U-0.52 U-0.36
   krypton U-0.70 U-0.52 U-0.48 U-0.32

Notes for Table C303.1.3(4)
  1. U-factors are applicable to both glass and plastic, flat and domed units, all spacers and gaps.
  2. Emissivities shall be less than or equal to the value specified.
  3. Gap fill shall be assumed to be air unless there is a minimum of 90% argon or krypton.
  4. Aluminum frame with thermal break is as defined in footnote 1 to Table C303.1.3(1).


TABLE C303.1.3(5)
SMALL BUSINESS COMPLIANCE TABLE
DEFAULT U-FACTORS FOR VERTICAL FENESTRATION
Vertical Fenestration Description Frame Type
Any Frame Aluminum
Thermal Break2
Wood/Vinyl/
Fiberglass
Panes Low-e1 Spacer Fill
Double3 A Any Argon 0.48 0.41 0.32
B Any Argon 0.46 0.39 0.30
C Any Argon 0.44 0.37 0.28
C High
Performance
Argon 0.42 0.35 Deemed to
comply5
Triple4 A Any Air 0.50 0.44 0.26
B Any Air 0.45 0.39 0.22
C Any Air 0.41 0.34 0.20
Any double
low-e
Any Air 0.35 0.32 0.18

  1. 1  Low-eA (emissivity) shall be 0.24 to 0.16.
    Low-eB (emissivity) shall be 0.15 to 0.08.
    Low-eC (emissivity) shall be 0.07 or less.
  2. 2 Aluminum Thermal Break = An aluminum thermal break framed window shall incorporate the following minimum design characteristics:
    1. The thermal conductivity of the thermal break material shall be not more than 3.6 Btu-in/h/ft2/°F;
    2. The thermal break material must produce a gap in the frame material of not less than 0.210 inches; and
    3. All metal framing members of the products exposed to interior and exterior air shall incorporate a thermal break meeting the criteria in a) and b) above.
  3. 3  A minimum air space of 0.375 inches between panes of glass is required for double glazing.
  4. 4  A minimum air space of 0.25 inches between panes of glass is required for triple glazing.
  5. 5  Deemed to comply glazing shall not be used for performance compliance.
  6.  

C303.1.4 Insulation Product Rating

AMENDMENT
This section has been amended at the state or city level.
The thermal resistance (R-value) of insulation shall be determined in accordance with the U.S. Federal Trade Commission R-value rule (C.F.R. Title 16, Part 460) in units of h × ft2 × °F/Btu at a mean temperature of 75°F (24°C).

C303.1.4.1 Insulated Siding

AMENDMENT
This section has been amended at the state or city level.
The thermal resistance (R-value) of insulated siding shall be determined in accordance with ASTM C1363. Installation for testing shall be in accordance with the manufacturer's installation instructions.

C303.2 Installation

AMENDMENT
This section has been amended at the state or city level.
Materials, systems and equipment shall be installed in accordance with the manufacturer's instructions and the International Building Code or International Residential Code, as applicable.
Insulation applied to the exterior of basement walls, crawlspace walls and the perimeter of slab-on-grade floors shall have a rigid, opaque and weather-resistant protective covering to prevent the degradation of the insulation's thermal performance. The protective covering shall cover the exposed exterior insulation and extend not less than 6 inches (153 mm) below grade.
Maintenance instructions shall be furnished for equipment and systems that require preventive maintenance. Required regular maintenance actions shall be clearly stated and incorporated on a readily accessible label. The label shall include the title or publication number for the operation and maintenance manual for that particular model and type of product.
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