3.5.4 Exterior Walls

Wall Name
Applicability All walls, optional input
Definition A unique name or code that relates the exterior wall to the design documents. This is an optional input since there are other acceptable ways to key surfaces to the construction documents.
Units Text, unique
Input Restrictions None
Baseline Rules None
Wall Type
Applicability All wall surfaces, optional
Definition One of four categories of above-grade wall assemblies used to determine minimum insulation requirements for walls. The four wall type categories are as follows: a) mass walls, b) metal building walls, c) metal framing walls, and d) wood framing and other walls. These wall types are defined in the baseline standards and the associated User's Manuals. The prescriptive criteria of the baseline standards depend on the wall type, but for green building ratings and tax deduction calculations, the PRM specifies that all baseline walls shall be “metal framed” so the input is not used for the purposes of this manual.
Units List: mass walls, metal building walls, metal framing walls, and wood framing and other walls
Input Restrictions This input is optional for the purposes covered by this manual. This input can often be derived from other inputs and may not need to be explicitly specified.
Baseline Rules All walls in the baseline building are modeled as “metal framed.”
Wall Geometry
Applicability All walls, required input
Definition Wall geometry defines the position, orientation, azimuth, and tilt of the wall surface. The details of how the coordinate system is implemented may vary between simulation engines. The data structure for surfaces is described in the reference section of this chapter.
Units Data structure: surface
Input Restrictions There are no restrictions other than that the surfaces defined must agree with the building being modeled, as represented on the construction drawings or as-built drawings.
Baseline Rules Wall geometry in the baseline building is identical to the proposed design.
Wall Construction
Applicability All walls, required input
Definition A reference to a construction assembly for the proposed design. See the building descriptors above for construction assemblies.
Units Dimensionless reference
Input Restrictions All wall surfaces must reference a construction assembly that meets the mandatory requirements of the appropriate baseline standard.
Baseline Rules Walls in the baseline building are all of the type “metal framed”. The insulation requirement is determined by the baseline standard and climate zone and is given in [bookref id="baseline-building-r-value-and-u-factor-criteria-for-walls"]. The baseline building construction shall be modeled as layers as defined in [bookref id="baseline-building-wall-construction-assemblies"].

[table title="Baseline Building R-value and U-factor Criteria for Walls" id="baseline-building-r-value-and-u-factor-criteria-for-walls"]

Applicable Standard Space Category Climate Zone Standard Design
Minimum Insulation Maximum Assembly
90.1 - 2001 Nonresidential 1-4 R-13 U-0.124
5,6 R-13 + R-3.8 c.i. U-0.084
7,8 R-13 + R-7.5 c.i. U-0.064
Residential 1,2 R-13 U-0.124
3 R-13 + R-3.8 c.i. U-0.084
4- 7 R-13 + R-7.5 c.i. U-0.064
8 R-13 + 10.0 c.i. U-0.055
Semi-Heated 1- 3 NR U-0.352
4 - 8 R-13 U-0.124
90.1 - 2007 Nonresidential 1,2 R-13 U-0.124
3 R-13 + R-3.8 c.i. U-0.084
4-8 R-13 + R-7.5 c.i. U-0.064
Residential 1 R-13 U-0.124
2-6 R-13 + R-7.5 c.i. U-0.064
7 R-13 +15.6 c.i. U-0.042
8 R-13 + R-18.8 c.i. U-0.037
Semi-Heated 1 NR U-0.352
2-7 R-13 U-0.124
8 R-13 + R-3.8 c.i. U-0.084

[table title="Baseline Building Wall Construction Assemblies" id="baseline-building-wall-construction-assemblies"]

Construction Layer Thickness (inch) Conductivity (Btu/h ft F) Density (lb/ft²) Specific Heat (Btu/lb F) R-value (ft²·°F·h/
Btu)
U-factor (Btu/
ft²·°F·h)
Wall R-13 + R-18.8 Air film         0.17  
Stucco 0.400 0.4167 116 0.2 0.08  
R-18.8 continuous insulation 1.800 0.0200 1.8 0.29 18.8  
Gypsum board 0.625 0.0930 50 0.2 0.56  
R-13 insulation/steel framing         6.00  
Gypsum board 0.625 0.0930 50 0.2 0.56  
Interior air film         0.68  
Total for assembly         26.85 0.037
Wall R-13 + R-15.6 Air film         0.17  
Stucco 0.400 0.4167 116 0.2 0.08  
R-15.6 continuous insulation 1.800 0.0200 1.8 0.29 15.6  
Gypsum board 0.625 0.0930 50 0.2 0.56  
R-13 insulation/steel framing         6.00  
Gypsum board 0.625 0.0930 50 0.2 0.56  
Interior air film         0.68  
Total for assembly         23.65 0.042
Wall R-13 + R-10.0 Air film         0.17  
Stucco 0.400 0.4167 116 0.2 0.08  
R-10.0continuous insulation 1.800 0.0200 1.8 0.29 10.0  
Gypsum board 0.625 0.0930 50 0.2 0.56  
R-13 insulation/steel framing         6.00  
Gypsum board 0.625 0.0930 50 0.2 0.56  
Interior air film         0.68  
Total for assembly         18.05 .055
Wall R-13 + R-7.5 Air film         0.17  
Stucco 0.400 0.4167 116 0.2 0.08  
R-7.5 continuous insulation 1.800 0.0200 1.8 0.29 7.50  
Gypsum board 0.625 0.0930 50 0.2 0.56  
R-13 insulation/steel framing         6.00  
Gypsum board 0.625 0.0930 50 0.2 0.56  
Interior air film         0.68  
Total for assembly         15.55 0.64
Wall R-13 + R-3.8 Air film         0.17  
Stucco 0.400 0.4167 116 0.2 0.08  
R-3.8 continuous insulation 0.912 0.0200 1.8 0.29 3.80  
Gypsum board 0.625 0.0930 50 0.2 0.56  
R-13 insulation/steel framing         6.00  
Gypsum board 0.625 0.0930 50 0.2 0.56  
Interior air film         0.68  
Total for assembly         11.85 0.84
Wall R-13 Air film         0.17  
Stucco 0.400 0.4167 116 0.2 0.08  
Gypsum board 0.625 0.0930 50 0.2 0.56  
R-13 insulation/steel framing         6.00  
Gypsum board 0.625 0.0930 50 0.2 0.56  
Interior air film         0.68  
Total for assembly         199.95 0.124
Wall R-13 Air film         0.17  
Stucco 0.400 0.4167 116 0.2 0.08  
Gypsum board 0.625 0.0930 50 0.2 0.56  
Cavity/steel framing         0.79  
Gypsum board 0.625 0.0930 50 0.2 0.56  
Interior air film         0.68  
Total for assembly         2.84 3.52
Exterior Wall Surface Properties
Applicability All walls
Definition

The exterior wall surface properties descriptor describes the characteristics of exterior wall surfaces. Exterior surface properties may include emissivity, reflectivity and roughness. The first two govern radiation exchange from the surface, while the latter governs the magnitude of the exterior air film resistance.

The descriptor is a critical default structure input, applicable to all models. Critical defaults require documentation to change. Data structures are outlined in the reference data structures section of this chapter.

Units Data structure: exterior surface properties
Input Restrictions The default value for emittance is 0.90. The default value for reflectance is 0.30. There is no default for roughness. The default values may be overridden only in cases when the lower reflectance can be documented by manufacturers’ literature or tests.
Baseline Rules The baseline building shall use default values for emittance and reflectance. The roughness of the baseline building walls shall be identical to the proposed design.
90.1-2007
Wall Name
Applicability All walls, optional input
Definition A unique name or code that relates the exterior wall to the design documents. This is an optional input since there are other acceptable ways to key surfaces to the construction documents.
Units Text, unique
Input Restrictions None
Baseline Rules None
Wall Type
Applicability All wall surfaces, optional
Definition One of four categories of above-grade wall assemblies used to determine minimum insulation requirements for walls. The four wall type categories are as follows: a) mass walls, b) metal building walls, c) metal framing walls, and d) wood framing and other walls. These wall types are defined in the baseline standards and the associated User's Manuals. The prescriptive criteria of the baseline standards depend on the wall type, but for green building ratings and tax deduction calculations, the PRM specifies that all baseline walls shall be “metal framed” so the input is not used for the purposes of this manual.
Units List: mass walls, metal building walls, metal framing walls, and wood framing and other walls
Input Restrictions This input is optional for the purposes covered by this manual. This input can often be derived from other inputs and may not need to be explicitly specified.
Baseline Rules All walls in the baseline building are modeled as “metal framed.”
Wall Geometry
Applicability All walls, required input
Definition Wall geometry defines the position, orientation, azimuth, and tilt of the wall surface. The details of how the coordinate system is implemented may vary between simulation engines. The data structure for surfaces is described in the reference section of this chapter.
Units Data structure: surface
Input Restrictions There are no restrictions other than that the surfaces defined must agree with the building being modeled, as represented on the construction drawings or as-built drawings.
Baseline Rules Wall geometry in the baseline building is identical to the proposed design.
Wall Construction
Applicability All walls, required input
Definition A reference to a construction assembly for the proposed design. See the building descriptors above for construction assemblies.
Units Dimensionless reference
Input Restrictions All wall surfaces must reference a construction assembly that meets the mandatory requirements of the appropriate baseline standard.
Baseline Rules Walls in the baseline building are all of the type “metal framed”. The insulation requirement is determined by the baseline standard and climate zone and is given in [bookref id="baseline-building-r-value-and-u-factor-criteria-for-walls"]. The baseline building construction shall be modeled as layers as defined in [bookref id="baseline-building-wall-construction-assemblies"].

[table title="Baseline Building R-value and U-factor Criteria for Walls" id="baseline-building-r-value-and-u-factor-criteria-for-walls"]

Applicable Standard Space Category Climate Zone Standard Design
Minimum Insulation Maximum Assembly
90.1 - 2007 Nonresidential 1,2 R-13 U-0.124
3 R-13 + R-3.8 c.i. U-0.084
4-8 R-13 + R-7.5 c.i. U-0.064
Residential 1 R-13 U-0.124
2-6 R-13 + R-7.5 c.i. U-0.064
7 R-13 +15.6 c.i. U-0.042
8 R-13 + R-18.8 c.i. U-0.037
Semi-Heated 1 NR U-0.352
2-7 R-13 U-0.124
8 R-13 + R-3.8 c.i. U-0.084

[table title="Baseline Building Wall Construction Assemblies" id="baseline-building-wall-construction-assemblies"]

Construction Layer Thickness (inch) Conductivity (Btu/h ft F) Density (lb/ft²) Specific Heat (Btu/lb F) R-value (ft²·°F·h/
Btu)
U-factor (Btu/
ft²·°F·h)
Wall R-13 + R-18.8 Air film         0.17  
Stucco 0.400 0.4167 116 0.2 0.08  
R-18.8 continuous insulation 1.800 0.0200 1.8 0.29 18.8  
Gypsum board 0.625 0.0930 50 0.2 0.56  
R-13 insulation/steel framing         6.00  
Gypsum board 0.625 0.0930 50 0.2 0.56  
Interior air film         0.68  
Total for assembly         26.85 0.037
Wall R-13 + R-15.6 Air film         0.17  
Stucco 0.400 0.4167 116 0.2 0.08  
R-15.6 continuous insulation 1.800 0.0200 1.8 0.29 15.6  
Gypsum board 0.625 0.0930 50 0.2 0.56  
R-13 insulation/steel framing         6.00  
Gypsum board 0.625 0.0930 50 0.2 0.56  
Interior air film         0.68  
Total for assembly         23.65 0.042
Wall R-13 + R-10.0 Air film         0.17  
Stucco 0.400 0.4167 116 0.2 0.08  
R-10.0continuous insulation 1.800 0.0200 1.8 0.29 10.0  
Gypsum board 0.625 0.0930 50 0.2 0.56  
R-13 insulation/steel framing         6.00  
Gypsum board 0.625 0.0930 50 0.2 0.56  
Interior air film         0.68  
Total for assembly         18.05 .055
Wall R-13 + R-7.5 Air film         0.17  
Stucco 0.400 0.4167 116 0.2 0.08  
R-7.5 continuous insulation 1.800 0.0200 1.8 0.29 7.50  
Gypsum board 0.625 0.0930 50 0.2 0.56  
R-13 insulation/steel framing         6.00  
Gypsum board 0.625 0.0930 50 0.2 0.56  
Interior air film         0.68  
Total for assembly         15.55 0.64
Wall R-13 + R-3.8 Air film         0.17  
Stucco 0.400 0.4167 116 0.2 0.08  
R-3.8 continuous insulation 0.912 0.0200 1.8 0.29 3.80  
Gypsum board 0.625 0.0930 50 0.2 0.56  
R-13 insulation/steel framing         6.00  
Gypsum board 0.625 0.0930 50 0.2 0.56  
Interior air film         0.68  
Total for assembly         11.85 0.84
Wall R-13 Air film         0.17  
Stucco 0.400 0.4167 116 0.2 0.08  
Gypsum board 0.625 0.0930 50 0.2 0.56  
R-13 insulation/steel framing         6.00  
Gypsum board 0.625 0.0930 50 0.2 0.56  
Interior air film         0.68  
Total for assembly         199.95 0.124
Wall R-13 Air film         0.17  
Stucco 0.400 0.4167 116 0.2 0.08  
Gypsum board 0.625 0.0930 50 0.2 0.56  
Cavity/steel framing         0.79  
Gypsum board 0.625 0.0930 50 0.2 0.56  
Interior air film         0.68  
Total for assembly         2.84 3.52
Exterior Wall Surface Properties
Applicability All walls
Definition

The exterior wall surface properties descriptor describes the characteristics of exterior wall surfaces. Exterior surface properties may include emissivity, reflectivity and roughness. The first two govern radiation exchange from the surface, while the latter governs the magnitude of the exterior air film resistance.

The descriptor is a critical default structure input, applicable to all models. Critical defaults require documentation to change. Data structures are outlined in the reference data structures section of this chapter.

Units Data structure: exterior surface properties
Input Restrictions The default value for emittance is 0.90. The default value for reflectance is 0.30. There is no default for roughness. The default values may be overridden only in cases when the lower reflectance can be documented by manufacturers’ literature or tests.
Baseline Rules The baseline building shall use default values for emittance and reflectance. The roughness of the baseline building walls shall be identical to the proposed design.
90.1-2010
Wall Name
Applicability All walls, optional input
Definition A unique name or code that relates the exterior wall to the design documents. This is an optional input since there are other acceptable ways to key surfaces to the construction documents.
Units Text, unique
Input Restrictions None
Baseline Rules None
Wall Type
Applicability All wall surfaces, optional
Definition One of four categories of above-grade wall assemblies used to determine minimum insulation requirements for walls. The four wall type categories are as follows: a) mass walls, b) metal building walls, c) metal framing walls, and d) wood framing and other walls. These wall types are defined in the baseline standards and the associated User's Manuals. The prescriptive criteria of the baseline standards depend on the wall type, but for green building ratings and tax deduction calculations, the PRM specifies that all baseline walls shall be “metal framed” so the input is not used for the purposes of this manual.
Units List: mass walls, metal building walls, metal framing walls, and wood framing and other walls
Input Restrictions This input is optional for the purposes covered by this manual. This input can often be derived from other inputs and may not need to be explicitly specified.
Baseline Rules All walls in the baseline building are modeled as “metal framed.”
Wall Geometry
Applicability All walls, required input
Definition Wall geometry defines the position, orientation, azimuth, and tilt of the wall surface. The details of how the coordinate system is implemented may vary between simulation engines. The data structure for surfaces is described in the reference section of this chapter.
Units Data structure: surface
Input Restrictions There are no restrictions other than that the surfaces defined must agree with the building being modeled, as represented on the construction drawings or as-built drawings.
Baseline Rules Wall geometry in the baseline building is identical to the proposed design.
Wall Construction
Applicability All walls, required input
Definition A reference to a construction assembly for the proposed design. See the building descriptors above for construction assemblies.
Units Dimensionless reference
Input Restrictions All wall surfaces must reference a construction assembly that meets the mandatory requirements of the appropriate baseline standard.
Baseline Rules Walls in the baseline building are all of the type “metal framed”. The insulation requirement is determined by the baseline standard and climate zone and is given in Table 6.5.4-1. The baseline building construction shall be modeled as layers as defined in Table 6.5.4-2.

Table 6.5.4-1: Baseline Building R-value and U-factor Criteria for Walls

Applicable Standard Space Category Climate Zone Standard Design
Minimum Insulation Maximum Assembly
90.1 - 2007 Nonresidential 1,2 R-13 U-0.124
3 R-13 + R-3.8 c.i. U-0.084
4-8 R-13 + R-7.5 c.i. U-0.064
Residential 1 R-13 U-0.124
2-6 R-13 + R-7.5 c.i. U-0.064
7 R-13 +15.6 c.i. U-0.042
8 R-13 + R-18.8 c.i. U-0.037
Semi-Heated 1 NR U-0.352
2-7 R-13 U-0.124
8 R-13 + R-3.8 c.i. U-0.084

Table 6.5.4-2: Baseline Building Wall Construction Assemblies

Construction Layer Thickness (inch) Conductivity (Btu/h ft F) Density (lb/ft²) Specific Heat (Btu/lb F) R-value (ft²·°F·h/
Btu)
U-factor (Btu/
ft²·°F·h)
Wall R-13 + R-18.8 Air film         0.17  
Stucco 0.400 0.4167 116 0.2 0.08  
R-18.8 continuous insulation 1.800 0.0200 1.8 0.29 18.8  
Gypsum board 0.625 0.0930 50 0.2 0.56  
R-13 insulation/steel framing         6.00  
Gypsum board 0.625 0.0930 50 0.2 0.56  
Interior air film         0.68  
Total for assembly         26.85 0.037
Wall R-13 + R-15.6 Air film         0.17  
Stucco 0.400 0.4167 116 0.2 0.08  
R-15.6 continuous insulation 1.800 0.0200 1.8 0.29 15.6  
Gypsum board 0.625 0.0930 50 0.2 0.56  
R-13 insulation/steel framing         6.00  
Gypsum board 0.625 0.0930 50 0.2 0.56  
Interior air film         0.68  
Total for assembly         23.65 0.042
Wall R-13 + R-10.0 Air film         0.17  
Stucco 0.400 0.4167 116 0.2 0.08  
R-10.0continuous insulation 1.800 0.0200 1.8 0.29 10.0  
Gypsum board 0.625 0.0930 50 0.2 0.56  
R-13 insulation/steel framing         6.00  
Gypsum board 0.625 0.0930 50 0.2 0.56  
Interior air film         0.68  
Total for assembly         18.05 .055
Wall R-13 + R-7.5 Air film         0.17  
Stucco 0.400 0.4167 116 0.2 0.08  
R-7.5 continuous insulation 1.800 0.0200 1.8 0.29 7.50  
Gypsum board 0.625 0.0930 50 0.2 0.56  
R-13 insulation/steel framing         6.00  
Gypsum board 0.625 0.0930 50 0.2 0.56  
Interior air film         0.68  
Total for assembly         15.55 0.64
Wall R-13 + R-3.8 Air film         0.17  
Stucco 0.400 0.4167 116 0.2 0.08  
R-3.8 continuous insulation 0.912 0.0200 1.8 0.29 3.80  
Gypsum board 0.625 0.0930 50 0.2 0.56  
R-13 insulation/steel framing         6.00  
Gypsum board 0.625 0.0930 50 0.2 0.56  
Interior air film         0.68  
Total for assembly         11.85 0.84
Wall R-13 Air film         0.17  
Stucco 0.400 0.4167 116 0.2 0.08  
Gypsum board 0.625 0.0930 50 0.2 0.56  
R-13 insulation/steel framing         6.00  
Gypsum board 0.625 0.0930 50 0.2 0.56  
Interior air film         0.68  
Total for assembly         199.95 0.124
Wall R-13 Air film         0.17  
Stucco 0.400 0.4167 116 0.2 0.08  
Gypsum board 0.625 0.0930 50 0.2 0.56  
Cavity/steel framing         0.79  
Gypsum board 0.625 0.0930 50 0.2 0.56  
Interior air film         0.68  
Total for assembly         2.84 3.52
Exterior Wall Surface Properties
Applicability All walls
Definition

The exterior wall surface properties descriptor describes the characteristics of exterior wall surfaces. Exterior surface properties may include emissivity, reflectivity and roughness. The first two govern radiation exchange from the surface, while the latter governs the magnitude of the exterior air film resistance.

The descriptor is a critical default structure input, applicable to all models. Critical defaults require documentation to change. Data structures are outlined in the reference data structures section of this chapter.

Units Data structure: exterior surface properties
Input Restrictions The default value for emittance is 0.90. The default value for reflectance is 0.30. There is no default for roughness. The default values may be overridden only in cases when the lower reflectance can be documented by manufacturers’ literature or tests.
Baseline Rules The baseline building shall use default values for emittance and reflectance. The roughness of the baseline building walls shall be identical to the proposed design.
90.1-2016 BM

Wall Name

Applicability

All walls, optional input

Definition

A unique name or code that relates the exterior wall to the design documents. This is an optional input since there are other acceptable ways to key surfaces to the construction documents.

Units

Text, unique

Input Restrictions

None

Baseline Rules

None

 

Wall Type

Applicability

All wall surfaces, optional

Definition

One of four categories of above-grade wall assemblies: a) mass walls, b) metal building walls, c) metal framing walls, and d) wood framing and other walls. These wall types are defined in Standard 90.1-2013 and the associated User's Manuals. The prescriptive criteria of the baseline standards depend on the wall type, but for performance calculations, the PRM specifies that all baseline walls shall be “metal framed”.

Units

List: mass walls, metal building walls, metal framing walls, and wood framing and other walls

Input Restrictions

This input is optional for the purposes covered by this manual. This input can often be derived from other inputs and may not need to be explicitly specified.

Baseline Rules

All walls in the baseline building are modeled as “metal framed.”

 

Wall Geometry

Applicability

All walls, required input

Definition

Wall geometry defines the position, orientation, azimuth, and tilt of the wall surface. The details of how the coordinate system is implemented may vary between simulation engines. The data structure for surfaces is described in the reference section of this chapter.

Units

Data structure: surface

Input Restrictions

The geometry of walls should match the construction documents or as-built drawings as accurately as possible.  Unusual curved surfaces may be approximated by a series of flat constructions.

Baseline Rules

Wall geometry in the baseline building is identical to the proposed design.

 

Wall Construction

Applicability

All walls, required input

Definition

A reference to a construction assembly for the proposed design. See the building descriptors above for construction assemblies.

Units

Dimensionless reference

Input Restrictions

All wall surfaces must reference a construction assembly that meets the mandatory requirements of Standard 90.1-2013.

Baseline Rules

Walls in the baseline building are all of the type “metal framed”. The insulation requirement is determined by the baseline standard and climate zone and is given in Table 3.5.4-1. The baseline building construction shall be modeled as layers as defined in Table 3.5.4-2.

Table 3.5.4-1: Baseline Building R-value and U-factor Criteria for Walls

Climate Zone

Nonresidential

Residential

Semi-Heated

Name

U-factor

Name

U-factor

Name

U-factor

1

R-13

0.124

R-13

0.124

NR

0.352

2

3

R-13+R-7.5 ci

0.064

R-13

0.124

4

R-13+R-3.8 ci

0.084

5

6

7

R-13+R-7.5 ci

0.064

8

R-13+R-10 ci

0.055

 

Table 3.5.4-2: Baseline Building Wall Construction Assemblies

Name

Layer

Thickness (inch)

Conductivity
(Btu/h ft F)

Density (lb/ft²)

Specific Heat (Btu/lb F)

R-value (ft²·°F·h/
Btu)

U-factor (Btu/
ft²·°F·h)

R-13 + R-10.0

Air film

       

0.17

 

Stucco

0.400

0.4167

116

0.2

0.08

 

R-10.0 continuous insulation

1.800

0.0200

1.8

0.29

10.0

 

Gypsum board

0.625

0.0930

50

0.2

0.56

 

R-13 insulation/steel framing

       

6.00

 

Gypsum board

0.625

0.0930

50

0.2

0.56

 

Interior air film

       

0.68

 

Total for assembly

       

18.05

.055

R-13 +
R-7.5

Air film

       

0.17

 

Stucco

0.400

0.4167

116

0.2

0.08

 

R-7.5 continuous insulation

1.800

0.0200

1.8

0.29

7.50

 

Gypsum board

0.625

0.0930

50

0.2

0.56

 

R-13 insulation/steel framing

       

6.00

 

Gypsum board

0.625

0.0930

50

0.2

0.56

 

Interior air film

       

0.68

 

Total for assembly

       

15.55

0.64

R-13 +
R-3.8

Air film

       

0.17

 

Stucco

0.400

0.4167

116

0.2

0.08

 

R-3.8 continuous insulation

0.912

0.0200

1.8

0.29

3.80

 

Gypsum board

0.625

0.0930

50

0.2

0.56

 

R-13 insulation/steel framing

       

6.00

 

Gypsum board

0.625

0.0930

50

0.2

0.56

 

Interior air film

       

0.68

 

Total for assembly

       

11.85

0.84

R-13

Air film

       

0.17

 

Stucco

0.400

0.4167

116

0.2

0.08

 

Gypsum board

0.625

0.0930

50

0.2

0.56

 

R-13 insulation/steel framing

       

6.00

 

Gypsum board

0.625

0.0930

50

0.2

0.56

 

Interior air film

       

0.68

 

Total for assembly

       

199.95

0.124

NR

Air film

       

0.17

 

Stucco

0.400

0.4167

116

0.2

0.08

 

Gypsum board

0.625

0.0930

50

0.2

0.56

 

Cavity/steel framing

       

0.79

 

Gypsum board

0.625

0.0930

50

0.2

0.56

 

Interior air film

       

0.68

 

Total for assembly

       

2.84

3.52

 

Exterior Wall Surface Properties

Applicability

All walls

Definition

The exterior wall surface properties descriptor describes the characteristics of exterior wall surfaces. Exterior surface properties may include emissivity, reflectivity and roughness. The first two govern radiation exchange from the surface, while the latter governs the magnitude of the exterior air film resistance.

Data structures are outlined in the reference data structures section of this chapter.

Units

Data structure: exterior surface properties

Input Restrictions

The default value for emittance is 0.90. The default value for reflectance is 0.30. There is no default for roughness. The default values may be overridden only in cases when the lower reflectance can be documented by manufacturers’ literature or tests.

Baseline Rules

The baseline building shall use default values for emittance and reflectance. The roughness of the baseline building walls shall be identical to the proposed design.

 

Building EQ
Wall Name
Applicability All walls, optional input
Definition A unique name or code that relates the exterior wall to the design documents. This is an optional input since there are other acceptable ways to key surfaces to the construction documents.
Units Text, unique
Input Restrictions None
Wall Geometry
Applicability All walls, required input
Definition Wall geometry defines the position, orientation, azimuth, and tilt of the wall surface. The details of how the coordinate system is implemented may vary between simulation engines. The data structure for surfaces is described in the reference section of this chapter.
Units Data structure: surface
Input Restrictions There are no restrictions other than that the surfaces defined must agree with the building being modeled, as represented on the construction drawings or as-built drawings.
Wall Construction
Applicability All walls, required input
Definition A reference to a construction assembly for the proposed design. See the building descriptors above for construction assemblies.
Units Dimensionless reference
Input Restrictions All wall surfaces must reference a construction assembly that meets the mandatory requirements of the appropriate baseline standard.

[table title="Baseline Building Wall Construction Assemblies" id="baseline-building-wall-construction-assemblies"]

Construction Layer Thickness (inch) Conductivity (Btu/h ft F) Density (lb/ft²) Specific Heat (Btu/lb F) R-value (ft²·°F·h/
Btu)
U-factor (Btu/
ft²·°F·h)
Wall R-13 + R-18.8 Air film         0.17  
Stucco 0.400 0.4167 116 0.2 0.08  
R-18.8 continuous insulation 1.800 0.0200 1.8 0.29 18.8  
Gypsum board 0.625 0.0930 50 0.2 0.56  
R-13 insulation/steel framing         6.00  
Gypsum board 0.625 0.0930 50 0.2 0.56  
Interior air film         0.68  
Total for assembly         26.85 0.037
Wall R-13 + R-15.6 Air film         0.17  
Stucco 0.400 0.4167 116 0.2 0.08  
R-15.6 continuous insulation 1.800 0.0200 1.8 0.29 15.6  
Gypsum board 0.625 0.0930 50 0.2 0.56  
R-13 insulation/steel framing         6.00  
Gypsum board 0.625 0.0930 50 0.2 0.56  
Interior air film         0.68  
Total for assembly         23.65 0.042
Wall R-13 + R-10.0 Air film         0.17  
Stucco 0.400 0.4167 116 0.2 0.08  
R-10.0continuous insulation 1.800 0.0200 1.8 0.29 10.0  
Gypsum board 0.625 0.0930 50 0.2 0.56  
R-13 insulation/steel framing         6.00  
Gypsum board 0.625 0.0930 50 0.2 0.56  
Interior air film         0.68  
Total for assembly         18.05 .055
Wall R-13 + R-7.5 Air film         0.17  
Stucco 0.400 0.4167 116 0.2 0.08  
R-7.5 continuous insulation 1.800 0.0200 1.8 0.29 7.50  
Gypsum board 0.625 0.0930 50 0.2 0.56  
R-13 insulation/steel framing         6.00  
Gypsum board 0.625 0.0930 50 0.2 0.56  
Interior air film         0.68  
Total for assembly         15.55 0.64
Wall R-13 + R-3.8 Air film         0.17  
Stucco 0.400 0.4167 116 0.2 0.08  
R-3.8 continuous insulation 0.912 0.0200 1.8 0.29 3.80  
Gypsum board 0.625 0.0930 50 0.2 0.56  
R-13 insulation/steel framing         6.00  
Gypsum board 0.625 0.0930 50 0.2 0.56  
Interior air film         0.68  
Total for assembly         11.85 0.84
Wall R-13 Air film         0.17  
Stucco 0.400 0.4167 116 0.2 0.08  
Gypsum board 0.625 0.0930 50 0.2 0.56  
R-13 insulation/steel framing         6.00  
Gypsum board 0.625 0.0930 50 0.2 0.56  
Interior air film         0.68  
Total for assembly         199.95 0.124
Wall R-13 Air film         0.17  
Stucco 0.400 0.4167 116 0.2 0.08  
Gypsum board 0.625 0.0930 50 0.2 0.56  
Cavity/steel framing         0.79  
Gypsum board 0.625 0.0930 50 0.2 0.56  
Interior air film         0.68  
Total for assembly         2.84 3.52
Exterior Wall Surface Properties
Applicability All walls
Definition

The exterior wall surface properties descriptor describes the characteristics of exterior wall surfaces. Exterior surface properties may include emissivity, reflectivity and roughness. The first two govern radiation exchange from the surface, while the latter governs the magnitude of the exterior air film resistance.

The descriptor is a critical default structure input, applicable to all models. Critical defaults require documentation to change. Data structures are outlined in the reference data structures section of this chapter.

Units Data structure: exterior surface properties
Input Restrictions The default value for emittance is 0.90. The default value for reflectance is 0.30. There is no default for roughness. The default values may be overridden only in cases when the lower reflectance can be documented by manufacturers’ literature or tests.
Energy Star
Wall Name
Applicability All walls, optional input
Definition A unique name or code that relates the exterior wall to the design documents. This is an optional input since there are other acceptable ways to key surfaces to the construction documents.
Units Text, unique
Input Restrictions None
Wall Geometry
Applicability All walls, required input
Definition Wall geometry defines the position, orientation, azimuth, and tilt of the wall surface. The details of how the coordinate system is implemented may vary between simulation engines. The data structure for surfaces is described in the reference section of this chapter.
Units Data structure: surface
Input Restrictions There are no restrictions other than that the surfaces defined must agree with the building being modeled, as represented on the construction drawings or as-built drawings.
Wall Construction
Applicability All walls, required input
Definition A reference to a construction assembly for the proposed design. See the building descriptors above for construction assemblies.
Units Dimensionless reference
Input Restrictions All wall surfaces must reference a construction assembly that meets the mandatory requirements of the appropriate baseline standard.

[table title="Baseline Building Wall Construction Assemblies" id="baseline-building-wall-construction-assemblies"]

Construction Layer Thickness (inch) Conductivity (Btu/h ft F) Density (lb/ft²) Specific Heat (Btu/lb F) R-value (ft²·°F·h/
Btu)
U-factor (Btu/
ft²·°F·h)
Wall R-13 + R-18.8 Air film         0.17  
Stucco 0.400 0.4167 116 0.2 0.08  
R-18.8 continuous insulation 1.800 0.0200 1.8 0.29 18.8  
Gypsum board 0.625 0.0930 50 0.2 0.56  
R-13 insulation/steel framing         6.00  
Gypsum board 0.625 0.0930 50 0.2 0.56  
Interior air film         0.68  
Total for assembly         26.85 0.037
Wall R-13 + R-15.6 Air film         0.17  
Stucco 0.400 0.4167 116 0.2 0.08  
R-15.6 continuous insulation 1.800 0.0200 1.8 0.29 15.6  
Gypsum board 0.625 0.0930 50 0.2 0.56  
R-13 insulation/steel framing         6.00  
Gypsum board 0.625 0.0930 50 0.2 0.56  
Interior air film         0.68  
Total for assembly         23.65 0.042
Wall R-13 + R-10.0 Air film         0.17  
Stucco 0.400 0.4167 116 0.2 0.08  
R-10.0continuous insulation 1.800 0.0200 1.8 0.29 10.0  
Gypsum board 0.625 0.0930 50 0.2 0.56  
R-13 insulation/steel framing         6.00  
Gypsum board 0.625 0.0930 50 0.2 0.56  
Interior air film         0.68  
Total for assembly         18.05 .055
Wall R-13 + R-7.5 Air film         0.17  
Stucco 0.400 0.4167 116 0.2 0.08  
R-7.5 continuous insulation 1.800 0.0200 1.8 0.29 7.50  
Gypsum board 0.625 0.0930 50 0.2 0.56  
R-13 insulation/steel framing         6.00  
Gypsum board 0.625 0.0930 50 0.2 0.56  
Interior air film         0.68  
Total for assembly         15.55 0.64
Wall R-13 + R-3.8 Air film         0.17  
Stucco 0.400 0.4167 116 0.2 0.08  
R-3.8 continuous insulation 0.912 0.0200 1.8 0.29 3.80  
Gypsum board 0.625 0.0930 50 0.2 0.56  
R-13 insulation/steel framing         6.00  
Gypsum board 0.625 0.0930 50 0.2 0.56  
Interior air film         0.68  
Total for assembly         11.85 0.84
Wall R-13 Air film         0.17  
Stucco 0.400 0.4167 116 0.2 0.08  
Gypsum board 0.625 0.0930 50 0.2 0.56  
R-13 insulation/steel framing         6.00  
Gypsum board 0.625 0.0930 50 0.2 0.56  
Interior air film         0.68  
Total for assembly         199.95 0.124
Wall R-13 Air film         0.17  
Stucco 0.400 0.4167 116 0.2 0.08  
Gypsum board 0.625 0.0930 50 0.2 0.56  
Cavity/steel framing         0.79  
Gypsum board 0.625 0.0930 50 0.2 0.56  
Interior air film         0.68  
Total for assembly         2.84 3.52
Exterior Wall Surface Properties
Applicability All walls
Definition

The exterior wall surface properties descriptor describes the characteristics of exterior wall surfaces. Exterior surface properties may include emissivity, reflectivity and roughness. The first two govern radiation exchange from the surface, while the latter governs the magnitude of the exterior air film resistance.

The descriptor is a critical default structure input, applicable to all models. Critical defaults require documentation to change. Data structures are outlined in the reference data structures section of this chapter.

Units Data structure: exterior surface properties
Input Restrictions The default value for emittance is 0.90. The default value for reflectance is 0.30. There is no default for roughness. The default values may be overridden only in cases when the lower reflectance can be documented by manufacturers’ literature or tests.