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
|
