3.5.9 Slab Floors in Contact with Ground

These building descriptors apply to slab-on-grade floors that are in direct contact with the ground.

Slab Floor Name
Applicability All slab floors, optional
Definition A unique name or code that relates the exposed floor to the construction documents.
Units Text, unique
Input Restrictions None
Baseline Rules Not applicable
Slab Floor Type
Applicability All slab floors, required
Definition One of two classes for floors in contact with ground. The classes are: 1) heated slab-on-grade floors and 2) unheated slab-on-grade floors. Heated slab-on-grade floors include all floors that are heated directly in order to provide heating to the space. Unheated slab-on-grade floors are all other floors in contact with ground. See the baseline standards and the associated User's Manuals for additional definition.
Units List: heated or unheated
Input Restrictions None
Baseline Rules Unheated
Slab Floor Geometry
Applicability All slab floors, required
Definition A geometric construct representing a slab floor in contact with the earth. The geometric representation can vary depending on how the energy simulation software models slabs-on-grade. Some models require that only the perimeter of the slab be entered. Other models divide the slab into a perimeter band within 2 ft of the edge and the interior portion or core area, such that the perimeter area and the core area sum to the total area of the slab.
Units Data structure: as appropriate for the simulation tool
Input Restrictions No restrictions
Baseline Rules Same as baseline building
Slab Floor Construction
Applicability All slab floors, required input
Definition

A description of how the slab is insulated (or not). How the construction is described will depend on the energy simulation model. Simple models may include just an F-factor, representing an instantaneous heat loss/gain to outside air. The F-factor could be related to the configuration of insulation in the proposed design. Other slab loss models may require that the surface area of the slab floor be divided between the perimeter and the interior. The insulation conditions then define heat transfer between both outside air and ground temperature.

The insulation condition for slabs includes the R-value of the insulation and the distance it extends into the earth at the slab edge and how far it extends underneath the slab.

Units Data structure: depends on the model that is used
Input Restrictions If the perimeter method is used to model the slab, F-factors shall be taken from Appendix A of ASHRAE Standard 90.1-2001 or ASHRAE Standard 90.1-2007. For all methods, inputs shall be consistent with the construction documents.
Baseline Rules Slab loss shall be modeled in the same manner in the baseline building as in the proposed design, e.g. if the perimeter method is used for the proposed design, the same method shall be used for the baseline building.
The configuration of insulation and the F-factors for the baseline building are shown in [bookref id="baseline-building-f-factor-criteria-for-slab-on-grade-floors"]. If the perimeter method is not used, then the F-factors from the table shall be used in the baseline building. If an alternative modeling method is used, then inputs to the method for the baseline building shall be consistent with the insulation configuration described in [bookref id="baseline-building-f-factor-criteria-for-slab-on-grade-floors"].

[table title="Baseline Building F-factor Criteria for Slab-on-Grade Floors" id="baseline-building-f-factor-criteria-for-slab-on-grade-floors"]

Applicable Standard Condition Space Category Climate Zone Baseline Building
Insulation Configuration F-Factor
90.1 – 2001 Unheated Nonresidential 1-7 NR 0.730
8 R-10 for 24 in. vertical 0.540
Residential 1-6 NR 0.730
7 R-10 for 24 in. vertical 0.540
8 R-15 for 24 in. vertical 0.520
Semi-Heated 1- 8 NR 0.730
Heated Nonresidential 1- 4 R-7.5 for 12 in. vertical 1.020
5- 7 R-10 for 36 in. vertical 0.840
8 R-10 for 48 in. vertical 0.780
Residential 1- 3 R-7.5 for 12 in. vertical 1.020
4, 5 R-10 for 36 in. vertical 0.840
6- 8 R-10 for 48 in. vertical 0.780
Semi-Heated 1- 7 R-7.5 for 12 in. vertical 1.020
8 R-7.5 for 24 in. vertical .0950
90.1 – 2007 Unheated Nonresidential 1-5 NR 0.730
6 R-10 for 24 in. vertical 0.540
7,8 R-15 for 24 in. vertical 0.520
Residential 1- 3 NR 0.730
4, 5 R-10 for 24 in. vertical 0.540
6, 7 R-15 for 24 in. vertical 0.520
8 R-20 for 24 in. vertical 0.510
Semi-Heated 1- 8 NR 0.730
Heated Nonresidential 1, 2 R-7.5 for 12 in. vertical 1.020
3 R-10 for 24 in. vertical 0.900
4- 6 R-15 for 24 in. vertical 0.860
7 R-20 for 24 in. vertical 0.843
8 R-20 for 48 in. vertical 0.688
Residential 1, 2 R-7.5 for 12 in. vertical 1.020
3 R-10 for 24 in. vertical 0.900
4, 5 R-15 for 24 in. vertical 0.860
6- 8 R-20 for 48 in. vertical 0.688
Semi-Heated 1- 6 R-7.5 for 12 in. vertical 1.020
7, 8 R-10 for 24 in. vertical 0.900
90.1-2007

These building descriptors apply to slab-on-grade floors that are in direct contact with the ground.

Slab Floor Name
Applicability All slab floors, optional
Definition A unique name or code that relates the exposed floor to the construction documents.
Units Text, unique
Input Restrictions None
Baseline Rules Not applicable
Slab Floor Type
Applicability All slab floors, required
Definition One of two classes for floors in contact with ground. The classes are: 1) heated slab-on-grade floors and 2) unheated slab-on-grade floors. Heated slab-on-grade floors include all floors that are heated directly in order to provide heating to the space. Unheated slab-on-grade floors are all other floors in contact with ground. See the baseline standards and the associated User's Manuals for additional definition.
Units List: heated or unheated
Input Restrictions None
Baseline Rules Unheated
Slab Floor Geometry
Applicability All slab floors, required
Definition A geometric construct representing a slab floor in contact with the earth. The geometric representation can vary depending on how the energy simulation software models slabs-on-grade. Some models require that only the perimeter of the slab be entered. Other models divide the slab into a perimeter band within 2 ft of the edge and the interior portion or core area, such that the perimeter area and the core area sum to the total area of the slab.
Units Data structure: as appropriate for the simulation tool
Input Restrictions No restrictions
Baseline Rules Same as baseline building
Slab Floor Construction
Applicability All slab floors, required input
Definition

A description of how the slab is insulated (or not). How the construction is described will depend on the energy simulation model. Simple models may include just an F-factor, representing an instantaneous heat loss/gain to outside air. The F-factor could be related to the configuration of insulation in the proposed design. Other slab loss models may require that the surface area of the slab floor be divided between the perimeter and the interior. The insulation conditions then define heat transfer between both outside air and ground temperature.

The insulation condition for slabs includes the R-value of the insulation and the distance it extends into the earth at the slab edge and how far it extends underneath the slab.

Units Data structure: depends on the model that is used
Input Restrictions If the perimeter method is used to model the slab, F-factors shall be taken from Appendix A of ASHRAE Standard 90.1-2007. For all methods, inputs shall be consistent with the construction documents.
Baseline Rules Slab loss shall be modeled in the same manner in the baseline building as in the proposed design, e.g. if the perimeter method is used for the proposed design, the same method shall be used for the baseline building.
The configuration of insulation and the F-factors for the baseline building are shown in [bookref id="baseline-building-f-factor-criteria-for-slab-on-grade-floors"]. If the perimeter method is not used, then the F-factors from the table shall be used in the baseline building. If an alternative modeling method is used, then inputs to the method for the baseline building shall be consistent with the insulation configuration described in [bookref id="baseline-building-f-factor-criteria-for-slab-on-grade-floors"].

[table title="Baseline Building F-factor Criteria for Slab-on-Grade Floors" id="baseline-building-f-factor-criteria-for-slab-on-grade-floors"]

Applicable Standard Condition Space Category Climate Zone Baseline Building
Insulation Configuration F-Factor
90.1 – 2007 Unheated Nonresidential 1-5 NR 0.730
6 R-10 for 24 in. vertical 0.540
7,8 R-15 for 24 in. vertical 0.520
Residential 1- 3 NR 0.730
4, 5 R-10 for 24 in. vertical 0.540
6, 7 R-15 for 24 in. vertical 0.520
8 R-20 for 24 in. vertical 0.510
Semi-Heated 1- 8 NR 0.730
Heated Nonresidential 1, 2 R-7.5 for 12 in. vertical 1.020
3 R-10 for 24 in. vertical 0.900
4- 6 R-15 for 24 in. vertical 0.860
7 R-20 for 24 in. vertical 0.843
8 R-20 for 48 in. vertical 0.688
Residential 1, 2 R-7.5 for 12 in. vertical 1.020
3 R-10 for 24 in. vertical 0.900
4, 5 R-15 for 24 in. vertical 0.860
6- 8 R-20 for 48 in. vertical 0.688
Semi-Heated 1- 6 R-7.5 for 12 in. vertical 1.020
7, 8 R-10 for 24 in. vertical 0.900
90.1-2010

These building descriptors apply to slab-on-grade floors that are in direct contact with the ground.

Slab Floor Name
Applicability All slab floors, optional
Definition A unique name or code that relates the exposed floor to the construction documents.
Units Text, unique
Input Restrictions None
Baseline Rules Not applicable
Slab Floor Type
Applicability All slab floors, required
Definition One of two classes for floors in contact with ground. The classes are: 1) heated slab-on-grade floors and 2) unheated slab-on-grade floors. Heated slab-on-grade floors include all floors that are heated directly in order to provide heating to the space. Unheated slab-on-grade floors are all other floors in contact with ground. See the baseline standards and the associated User's Manuals for additional definition.
Units List: heated or unheated
Input Restrictions None
Baseline Rules Unheated
Slab Floor Geometry
Applicability All slab floors, required
Definition A geometric construct representing a slab floor in contact with the earth. The geometric representation can vary depending on how the energy simulation software models slabs-on-grade. Some models require that only the perimeter of the slab be entered. Other models divide the slab into a perimeter band within 2 ft of the edge and the interior portion or core area, such that the perimeter area and the core area sum to the total area of the slab.
Units Data structure: as appropriate for the simulation tool
Input Restrictions No restrictions
Baseline Rules Same as baseline building
Slab Floor Construction
Applicability All slab floors, required input
Definition

A description of how the slab is insulated (or not). How the construction is described will depend on the energy simulation model. Simple models may include just an F-factor, representing an instantaneous heat loss/gain to outside air. The F-factor could be related to the configuration of insulation in the proposed design. Other slab loss models may require that the surface area of the slab floor be divided between the perimeter and the interior. The insulation conditions then define heat transfer between both outside air and ground temperature.

The insulation condition for slabs includes the R-value of the insulation and the distance it extends into the earth at the slab edge and how far it extends underneath the slab.

Units Data structure: depends on the model that is used
Input Restrictions If the perimeter method is used to model the slab, F-factors shall be taken from Appendix A of ASHRAE Standard 90.1-2007. For all methods, inputs shall be consistent with the construction documents.
Baseline Rules Slab loss shall be modeled in the same manner in the baseline building as in the proposed design, e.g. if the perimeter method is used for the proposed design, the same method shall be used for the baseline building.
The configuration of insulation and the F-factors for the baseline building are shown in Table 6.5.9-1. If the perimeter method is not used, then the F-factors from the table shall be used in the baseline building. If an alternative modeling method is used, then inputs to the method for the baseline building shall be consistent with the insulation configuration described in Table 6.5.9-1.

Table 6.5.9-1: Baseline Building F-factor Criteria for Slab-on-Grade Floors

Applicable Standard Condition Space Category Climate Zone Baseline Building
Insulation Configuration F-Factor
90.1 – 2007 Unheated Nonresidential 1-5 NR 0.730
6 R-10 for 24 in. vertical 0.540
7,8 R-15 for 24 in. vertical 0.520
Residential 1- 3 NR 0.730
4, 5 R-10 for 24 in. vertical 0.540
6, 7 R-15 for 24 in. vertical 0.520
8 R-20 for 24 in. vertical 0.510
Semi-Heated 1- 8 NR 0.730
Heated Nonresidential 1, 2 R-7.5 for 12 in. vertical 1.020
3 R-10 for 24 in. vertical 0.900
4- 6 R-15 for 24 in. vertical 0.860
7 R-20 for 24 in. vertical 0.843
8 R-20 for 48 in. vertical 0.688
Residential 1, 2 R-7.5 for 12 in. vertical 1.020
3 R-10 for 24 in. vertical 0.900
4, 5 R-15 for 24 in. vertical 0.860
6- 8 R-20 for 48 in. vertical 0.688
Semi-Heated 1- 6 R-7.5 for 12 in. vertical 1.020
7, 8 R-10 for 24 in. vertical 0.900
90.1-2016 BM

These building descriptors apply to slab-on-grade floors that are in direct contact with the ground. 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.

 

Slab Floor Name

Applicability

All slab floors, optional

Definition

A unique name or code that relates the exposed floor to the construction documents.

Units

Text, unique

Input Restrictions

None

Baseline Rules

Not applicable

 

Slab Floor Type

Applicability

All slab floors, required

Definition

One of two classes for floors in contact with ground. The classes are: 1) heated slab-on-grade floors and 2) unheated slab-on-grade floors. Heated slab-on-grade floors include all floors that are heated directly in order to provide heating to the space. Unheated slab-on-grade floors are all other floors in contact with ground.

Units

List: heated or unheated

Input Restrictions

None

Baseline Rules

The baseline building slab floor is unheated.

 

Slab Floor Geometry

Applicability

All slab floors, required

Definition

A geometric construct representing a slab floor in contact with the earth. The geometric representation can vary depending on how the energy simulation software models slabs-on-grade. Some models require that only the perimeter of the slab be entered. Other models divide the slab into a perimeter band within 2 ft of the edge and the interior portion or core area, such that the perimeter area and the core area sum to the total area of the slab.

Units

Data structure: as appropriate for the simulation tool which may include area, perimeter or other information

Input Restrictions

No restrictions

Baseline Rules

Same as baseline building

 

Slab Floor Construction

Applicability

All slab floors, required input

Definition

A description of how the slab is insulated (or not). How the construction is described will depend on the energy simulation model. Simple models may include just an F-factor, representing an instantaneous heat loss/gain to outside air. The F-factor could be related to the configuration of insulation in the proposed design. Other slab loss models may require that the surface area of the slab floor be divided between the perimeter and the interior. The insulation conditions then define heat transfer between both outside air and ground temperature.

The insulation condition for slabs includes the R-value of the insulation and the distance it extends into the earth at the slab edge and how far it extends underneath the slab.

Units

Data structure: depends on the model that is used

Input Restrictions

If the perimeter method is used to model the slab, F-factors shall be taken from Appendix A of ASHRAE Standard 90.1-2013. For all methods, inputs shall be consistent with the construction documents.

Baseline Rules

Slab loss shall be modeled in the same manner in the baseline building as in the proposed design, e.g. if the perimeter method is used for the proposed design, the same method shall be used for the baseline building.
The configuration of insulation and the F-factors for the baseline building are shown in Table 3.5.9-1. If the perimeter method is not used, then the F-factors from the table shall be used in the baseline building. If an alternative modeling method is used, then inputs to the method for the baseline building shall be consistent with the insulation configuration described in Table 3.5.9-1.

Table 3.5.9-1: Baseline Building F-factor Criteria for Slab-on-Grade Floors

 

Nonresidential

Residential

Semi-Heated

Climate Zone

Name

F-factor

Name

F-factor

Name

F-factor

1

NR

0.730

NR

0.730

NR

0.730

2

3

4

5

6

7

R-10 for 24 in. v

0.540

8

R-10 for 24 in. v

0.540

R-15 for 24 in. v

0.520

Building EQ

These building descriptors apply to slab-on-grade floors that are in direct contact with the ground.

Slab Floor Name
Applicability All slab floors, optional
Definition A unique name or code that relates the exposed floor to the construction documents.
Units Text, unique
Input Restrictions None
Slab Floor Geometry
Applicability All slab floors, required
Definition A geometric construct representing a slab floor in contact with the earth. The geometric representation can vary depending on how the energy simulation software models slabs-on-grade. Some models require that only the perimeter of the slab be entered. Other models divide the slab into a perimeter band within 2 ft of the edge and the interior portion or core area, such that the perimeter area and the core area sum to the total area of the slab.
Units Data structure: as appropriate for the simulation tool
Input Restrictions No restrictions
Slab Floor Construction
Applicability All slab floors, required input
Definition

A description of how the slab is insulated (or not). How the construction is described will depend on the energy simulation model. Simple models may include just an F-factor, representing an instantaneous heat loss/gain to outside air. The F-factor could be related to the configuration of insulation in the proposed design. Other slab loss models may require that the surface area of the slab floor be divided between the perimeter and the interior. The insulation conditions then define heat transfer between both outside air and ground temperature.

The insulation condition for slabs includes the R-value of the insulation and the distance it extends into the earth at the slab edge and how far it extends underneath the slab.

Units Data structure: depends on the model that is used
Input Restrictions If the perimeter method is used to model the slab, F-factors shall be taken from Appendix A of ASHRAE Standard 90.1-2001 or ASHRAE Standard 90.1-2007. For all methods, inputs shall be consistent with the construction documents.
Energy Star

These building descriptors apply to slab-on-grade floors that are in direct contact with the ground.

Slab Floor Name
Applicability All slab floors, optional
Definition A unique name or code that relates the exposed floor to the construction documents.
Units Text, unique
Input Restrictions None
Slab Floor Geometry
Applicability All slab floors, required
Definition A geometric construct representing a slab floor in contact with the earth. The geometric representation can vary depending on how the energy simulation software models slabs-on-grade. Some models require that only the perimeter of the slab be entered. Other models divide the slab into a perimeter band within 2 ft of the edge and the interior portion or core area, such that the perimeter area and the core area sum to the total area of the slab.
Units Data structure: as appropriate for the simulation tool
Input Restrictions No restrictions
Slab Floor Construction
Applicability All slab floors, required input
Definition

A description of how the slab is insulated (or not). How the construction is described will depend on the energy simulation model. Simple models may include just an F-factor, representing an instantaneous heat loss/gain to outside air. The F-factor could be related to the configuration of insulation in the proposed design. Other slab loss models may require that the surface area of the slab floor be divided between the perimeter and the interior. The insulation conditions then define heat transfer between both outside air and ground temperature.

The insulation condition for slabs includes the R-value of the insulation and the distance it extends into the earth at the slab edge and how far it extends underneath the slab.

Units Data structure: depends on the model that is used
Input Restrictions If the perimeter method is used to model the slab, F-factors shall be taken from Appendix A of ASHRAE Standard 90.1-2001 or ASHRAE Standard 90.1-2007. For all methods, inputs shall be consistent with the construction documents.