3.5.1 Materials

Energy simulation programs commonly define construction assemblies by listing a sequence of materials that make up that construction assembly. Appendix D has a list of standard materials that may be referenced by construction assemblies. Additional materials not listed in Appendix D may be defined as described below. Alternate methods may be used to define construction assemblies such as specifying the U-factor and optionally, a metric describing thermal mass such as heat capacity (HC). These alternate methods may not require identification of materials. When a material is defined, all of the properties listed below must be defined. Some materials listed in Appendix D are non-homogeneous, for instance, framing members with insulation in the cavity.

Material Name
Applicability	When construction assemblies reference materials that are not standard
Definition	The name of a construction material used in the exterior envelope of the building
Units	Text, unique
Input Restrictions	Material name is a required input for materials not available from the standard list. The user may not modify entries for predefined materials.
Baseline Rules	Not applicable

Density
Applicability	All non-standard materials
Definition	The density (or mass per unit of volume) of the construction material as documented in an ASHRAE handbook, a comparably reliable reference, or manufacturers’ literature.
Units	Numeric input: lb/ft3
Input Restrictions	Density is a required input when non-standard materials are specified.
Baseline Rules	Not applicable

Specific Heat
Applicability	All non-standard materials
Definition	The specific heat capacity of a material is numerically equal to the quantity of heat that must be supplied to a unit mass of the material to increase its temperature by 1 degree F.
Units	Btu/lb•°F
Input Restrictions	Specific heat is a required input when non-standard materials are specified. The specific heat capacity of the construction material as documented in an ASHRAE handbook, a comparably reliable reference, or manufacturers’ literature.
Baseline Rules	Not applicable

Thermal Conductivity
Applicability	All non-standard materials
Definition	The thermal conductivity of a material of unit thickness is numerically equal to the quantity of heat that will flow through a unit area of the material when the temperature difference through the material is 1 degree F.
Units	Btu/h•ft•°F
Input Restrictions	Thermal conductivity is a required input for non-standard materials.
Baseline Rules	Not applicable

Thickness
Applicability	All non-standard materials
Definition	The thickness of a material
Units	ft or in. (cm)
Input Restrictions	Thickness is a required input for non-standard materials. The user shall document the data source for thermal conductivity used for additional materials under the material name descriptor.
Baseline Rules	Not applicable

90.1-2019

Energy simulation programs commonly define construction assemblies by listing a sequence of material layers that make up the construction assembly. Typical construction assemblies and their respective material layers are defined in Normative Appendix A of Standard 90.1-2019.

*Material Name*
Applicability	When construction assemblies reference materials that are not standard
Definition	The name of a construction material used in the exterior envelope of the building
Units	Text, unique
Input Restrictions	Material name is a required input for materials not available from the standard list. The user may not modify entries for predefined materials.
Baseline Building	Not applicable

*Density*
Applicability	All non-standard materials
Definition	The density (or mass per unit of volume) of the construction material
Units	lb/ft³
Input Restrictions	Density is a required input when non-standard materials are specified as documented in an ASHRAE handbook, a comparably reliable reference, or manufacturers’ literature
Baseline Building	Not applicable

*Specific Heat*
Applicability	All non-standard materials
Definition	The specific heat capacity of a material is numerically equal to the quantity of heat that must be supplied to a unit mass of the material to increase its temperature by 1°F
Units	Btu/lb·°F
Input Restrictions	Specific heat is a required input when non-standard materials are specified. The specific heat capacity of the construction material as documented in an ASHRAE handbook, a comparably reliable reference, or manufacturers’ literature.
Baseline Building	Not applicable

*Thermal Conductivity*
Applicability	All non-standard materials
Definition	The thermal conductivity of a material of unit thickness is numerically equal to the quantity of heat that will flow through a unit area of the material when the temperature difference through the material is 1 °F.
Units	Btu/h·ft·°F
Input Restrictions	Thermal conductivity is a required input for non-standard materials as documented in an ASHRAE handbook, a comparably reliable reference, or manufacturers’ literature.
Baseline Building	Not applicable

*Thickness*
Applicability	All non-standard materials
Definition	The thickness of a material
Units	ft or in.
Input Restrictions	Thickness is a required input for non-standard materials
Baseline Building	Not applicable