3.5.8 Below Grade Walls

Below Grade Wall Name
Applicability All projects, optional input
Definition A unique name that keys the below grade wall to the construction documents
Units Text, unique
Input Restrictions None
Baseline Rules Not applicable
Below Grade Wall Geometry
Applicability All projects
Definition A geometric construct that describes the dimensions and placement of walls located below grade. Below grade walls have soil or crushed rock on one side and interior space on the other side. Some simulation models take the depth below grade into account when estimating heat transfer, so the geometry may include height and width.
Units Data structure: below grade wall geometry
Input Restrictions There are no restrictions other than that the inputs shall be in agreement with the construction documents.
Baseline Rules The geometry of below grade walls in the baseline building is identical to the below grade walls in the proposed design.
Below Grade Wall Construction
Applicability All projects, required input
Definition A description of the manner in which a below grade wall is constructed or a representation of the thermal performance of the below grade wall that can be used by the energy simulation software to estimate heat transfer. The construction can be described as a C-factor which is similar to a U-factor, except that the outside air film is excluded or the construction can be represented as a series of layers, like exterior constructions.
Units Data structure: construction assembly
Input Restrictions No restrictions other than that the inputs shall be in agreement with the construction documents.
Baseline Rules See [bookref id="baseline-building-c-factor-criteria-for-below-grade-walls"] and [bookref id="baseline-building-below-grade-wall-construction-assemblies"].

[table title="Baseline Building C-factor Criteria for Below-Grade Walls" id="baseline-building-c-factor-criteria-for-below-grade-walls"]

Applicable Standard Space Category Climate Zone Standard Design
Minimum Insulation C-Factor
90.1 - 2001 Nonresidential 1- 6 NR 1.140
7, 8 R-7.5 c.i. 0.119
Residential 1-5 NR 1.140
6- 8 R-7.5 c.i. 0.119
Semi-Heated 1-8 NR 1.140
90.1 - 2007 Nonresidential 1- 4 NR 1.140
5678 R-7.5 c.i. 0.119
Residential 1-3 NR 1.140
456 R-7.5 c.i. 0.119
7 R-10 c.i. 0.092
8 R-12.5 c.i. 0.075
Semi-Heated 1- 8 NR 1.140

[table title="Baseline Building Below-Grade Wall Construction Assemblies" id="baseline-building-below-grade-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) C-factor (Btu/ft²·°F·h)
NR 115 lb/ft3 CMU, solid grout 8 0.45 115 0.20 0.87 1.140
R-7.5 c.i. 115 lb/ft3 CMU, solid grout 8 0.45 115 0.20 0.87  
  R-10 continuous insulation 1.8 0.02 1.8 0.29 7.50  
  Total assembly         8.37 0.119
R-10 c.i. 115 lb/ft3 CMU, solid grout 8 0.45 115 0.20 0.87  
  R-10 continuous insulation 2.4 0.02 1.8 0.29 10.00  
  Total assembly         10.87 0.092
R-12.5 c.i. 115 lb/ft3 CMU, solid grout 8 0.45 115 0.20 0.87  
  R-10 continuous insulation 3.0 0.02 1.8 0.29 12.50  
  Total assembly         13.37 0.075
90.1-2007
Below Grade Wall Name
Applicability All projects, optional input
Definition A unique name that keys the below grade wall to the construction documents
Units Text, unique
Input Restrictions None
Baseline Rules Not applicable
Below Grade Wall Geometry
Applicability All projects
Definition A geometric construct that describes the dimensions and placement of walls located below grade. Below grade walls have soil or crushed rock on one side and interior space on the other side. Some simulation models take the depth below grade into account when estimating heat transfer, so the geometry may include height and width.
Units Data structure: below grade wall geometry
Input Restrictions There are no restrictions other than that the inputs shall be in agreement with the construction documents.
Baseline Rules The geometry of below grade walls in the baseline building is identical to the below grade walls in the proposed design.
Below Grade Wall Construction
Applicability All projects, required input
Definition A description of the manner in which a below grade wall is constructed or a representation of the thermal performance of the below grade wall that can be used by the energy simulation software to estimate heat transfer. The construction can be described as a C-factor which is similar to a U-factor, except that the outside air film is excluded or the construction can be represented as a series of layers, like exterior constructions.
Units Data structure: construction assembly
Input Restrictions No restrictions other than that the inputs shall be in agreement with the construction documents.
Baseline Rules See [bookref id="baseline-building-c-factor-criteria-for-below-grade-walls"] and [bookref id="baseline-building-below-grade-wall-construction-assemblies"].

[table title="Baseline Building C-factor Criteria for Below-Grade Walls" id="baseline-building-c-factor-criteria-for-below-grade-walls"]

Applicable Standard Space Category Climate Zone Standard Design
Minimum Insulation C-Factor
90.1 - 2007 Nonresidential 1- 4 NR 1.140
5678 R-7.5 c.i. 0.119
Residential 1-3 NR 1.140
456 R-7.5 c.i. 0.119
7 R-10 c.i. 0.092
8 R-12.5 c.i. 0.075
Semi-Heated 1- 8 NR 1.140

[table title="Baseline Building Below-Grade Wall Construction Assemblies" id="baseline-building-below-grade-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) C-factor (Btu/ft²·°F·h)
NR 115 lb/ft3 CMU, solid grout 8 0.45 115 0.20 0.87 1.140
R-7.5 c.i. 115 lb/ft3 CMU, solid grout 8 0.45 115 0.20 0.87  
  R-10 continuous insulation 1.8 0.02 1.8 0.29 7.50  
  Total assembly         8.37 0.119
R-10 c.i. 115 lb/ft3 CMU, solid grout 8 0.45 115 0.20 0.87  
  R-10 continuous insulation 2.4 0.02 1.8 0.29 10.00  
  Total assembly         10.87 0.092
R-12.5 c.i. 115 lb/ft3 CMU, solid grout 8 0.45 115 0.20 0.87  
  R-10 continuous insulation 3.0 0.02 1.8 0.29 12.50  
  Total assembly         13.37 0.075
90.1-2010
Below Grade Wall Name
Applicability All projects, optional input
Definition A unique name that keys the below grade wall to the construction documents
Units Text, unique
Input Restrictions None
Baseline Rules Not applicable
Below Grade Wall Geometry
Applicability All projects
Definition A geometric construct that describes the dimensions and placement of walls located below grade. Below grade walls have soil or crushed rock on one side and interior space on the other side. Some simulation models take the depth below grade into account when estimating heat transfer, so the geometry may include height and width.
Units Data structure: below grade wall geometry
Input Restrictions There are no restrictions other than that the inputs shall be in agreement with the construction documents.
Baseline Rules The geometry of below grade walls in the baseline building is identical to the below grade walls in the proposed design.
Below Grade Wall Construction
Applicability All projects, required input
Definition A description of the manner in which a below grade wall is constructed or a representation of the thermal performance of the below grade wall that can be used by the energy simulation software to estimate heat transfer. The construction can be described as a C-factor which is similar to a U-factor, except that the outside air film is excluded or the construction can be represented as a series of layers, like exterior constructions.
Units Data structure: construction assembly
Input Restrictions No restrictions other than that the inputs shall be in agreement with the construction documents.
Baseline Rules See Table 6.5.8-1 and Table 6.5.8-2.

Table 6.5.8-1: Baseline Building C-factor Criteria for Below-Grade Walls

Applicable Standard Space Category Climate Zone Standard Design
Minimum Insulation C-Factor
90.1 - 2007 Nonresidential 1- 4 NR 1.140
5678 R-7.5 c.i. 0.119
Residential 1-3 NR 1.140
456 R-7.5 c.i. 0.119
7 R-10 c.i. 0.092
8 R-12.5 c.i. 0.075
Semi-Heated 1- 8 NR 1.140

Table 6.5.8-2: Baseline Building Below-Grade 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) C-factor (Btu/ft²·°F·h)
NR 115 lb/ft3 CMU, solid grout 8 0.45 115 0.20 0.87 1.140
R-7.5 c.i. 115 lb/ft3 CMU, solid grout 8 0.45 115 0.20 0.87  
  R-10 continuous insulation 1.8 0.02 1.8 0.29 7.50  
  Total assembly         8.37 0.119
R-10 c.i. 115 lb/ft3 CMU, solid grout 8 0.45 115 0.20 0.87  
  R-10 continuous insulation 2.4 0.02 1.8 0.29 10.00  
  Total assembly         10.87 0.092
R-12.5 c.i. 115 lb/ft3 CMU, solid grout 8 0.45 115 0.20 0.87  
  R-10 continuous insulation 3.0 0.02 1.8 0.29 12.50  
  Total assembly         13.37 0.075
90.1-2016 BM

Heat transfer from below-grade walls may be modeled using a constant annual or monthly ground temperature. The temperatures from table 3.9.1-1 may be used as a default.

 

Below-Grade Wall Name

Applicability

All projects, optional input

Definition

A unique name that keys the below grade wall to the construction documents

Units

Text, unique

Input Restrictions

None

Baseline Rules

Not applicable

 

Below-Grade Wall Geometry

Applicability

All projects

Definition

A geometric construct that describes the dimensions and placement of walls located below grade. Below grade walls have soil or crushed rock on one side and interior space on the other side. Some simulation models take the depth below grade into account when estimating heat transfer, so the geometry may include height and width.

Units

Data structure: below grade wall geometry

Input Restrictions

There are no restrictions other than that the inputs shall be in agreement with the construction documents.

Baseline Rules

The geometry of below grade walls in the baseline building is identical to the below grade walls in the proposed design.

 

Below-Grade Wall Construction

Applicability

All projects, required input

Definition

A description of the manner in which a below grade wall is constructed or a representation of the thermal performance of the below grade wall that can be used by the energy simulation software to estimate heat transfer. The construction can be described as a C-factor which is similar to a U-factor, except that the outside air film is excluded or the construction can be represented as a series of layers, like exterior constructions.

Units

Data structure: construction assembly

Input Restrictions

No restrictions other than that the inputs shall be in agreement with the construction documents.

Baseline Rules

See Table 3.5.8-1 and Table 3.5.8-2.

Table 3.5.8-1: Baseline Building C-factor Criteria for Below-Grade Walls

 

Nonresidential

Residential

Semi-Heated

Climate Zone

Name

C-factor

Name

C-factor

Name

C-factor

1

NR

1.140

NR

1.140

NR

1.140

2

3

4

5

6

R-7.5 ci

0.119

7

R-7.5 ci

0.119

8

 

Table 3.5.8-2: Baseline Building Below-Grade 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)

C-factor (Btu/ft²·°F·h)

NR

115 lb/ft3 CMU, solid grout

8

0.45

115

0.20

0.87

1.140

R-7.5 c.i.

115 lb/ft3 CMU, solid grout

8

0.45

115

0.20

0.87

 

 

R-10 continuous insulation

1.8

0.02

1.8

0.29

7.50

 

 

Total assembly

 

 

 

 

8.37

0.119

Building EQ
Below Grade Wall Name
Applicability All projects, optional input
Definition A unique name that keys the below grade wall to the construction documents
Units Text, unique
Input Restrictions None
Below Grade Wall Geometry
Applicability All projects
Definition A geometric construct that describes the dimensions and placement of walls located below grade. Below grade walls have soil or crushed rock on one side and interior space on the other side. Some simulation models take the depth below grade into account when estimating heat transfer, so the geometry may include height and width.
Units Data structure: below grade wall geometry
Input Restrictions There are no restrictions other than that the inputs shall be in agreement with the construction documents.
Below Grade Wall Construction
Applicability All projects, required input
Definition A description of the manner in which a below grade wall is constructed or a representation of the thermal performance of the below grade wall that can be used by the energy simulation software to estimate heat transfer. The construction can be described as a C-factor which is similar to a U-factor, except that the outside air film is excluded or the construction can be represented as a series of layers, like exterior constructions.
Units Data structure: construction assembly
Input Restrictions No restrictions other than that the inputs shall be in agreement with the construction documents.
Energy Star
Below Grade Wall Name
Applicability All projects, optional input
Definition A unique name that keys the below grade wall to the construction documents
Units Text, unique
Input Restrictions None
Below Grade Wall Geometry
Applicability All projects
Definition A geometric construct that describes the dimensions and placement of walls located below grade. Below grade walls have soil or crushed rock on one side and interior space on the other side. Some simulation models take the depth below grade into account when estimating heat transfer, so the geometry may include height and width.
Units Data structure: below grade wall geometry
Input Restrictions There are no restrictions other than that the inputs shall be in agreement with the construction documents.
Below Grade Wall Construction
Applicability All projects, required input
Definition A description of the manner in which a below grade wall is constructed or a representation of the thermal performance of the below grade wall that can be used by the energy simulation software to estimate heat transfer. The construction can be described as a C-factor which is similar to a U-factor, except that the outside air film is excluded or the construction can be represented as a series of layers, like exterior constructions.
Units Data structure: construction assembly
Input Restrictions No restrictions other than that the inputs shall be in agreement with the construction documents.