Energy simulation programs commonly define construction assemblies by listing a sequence of material layers that make up the construction assembly. Appendix 5.5 has a list of standard materials that may be referenced by construction assemblies. 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 5.5 are non-homogeneous, for instance, framing members with insulation in the cavity. The properties of each material layer can be found in ACM Appendix 5.5.
Material Name
Applicability: Opaque constructions.
Definition: The name of a construction material used.
Units: Text: unique.
Input Restrictions: Material name is a required input for materials not available from the standard list in ACM Appendix 5.5. The user may not modify entries for predefined materials.
Standard Design: Not applicable.
Standard Design: Existing Buildings: Not applicable.
Density
Applicability: Opaque constructions.
Definition: The density, mass per unit volume, of the construction material as documented in Appendix 5.5A.
Units: lb/ft3.
Input Restrictions: Prescribed from Appendix 5.5.
Standard Design: Not applicable.
Standard Design: Existing Buildings: Not applicable.
Specific Heat
Applicability: Opaque constructions.
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: Prescribed from Appendix 5.5.
Standard Design: Not applicable.
Standard Design: Existing Buildings: 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/lb·°F.
Input Restrictions: Prescribed from Appendix 5.5.
Standard Design: Not applicable.
Standard Design: Existing Buildings: Not applicable.
Thickness
Applicability: All non-standard materials.
Definition: The thickness of a material.
Units: Inches.
Input Restrictions: Prescribed from Appendix 5.5.
Standard Design: Not applicable.
Standard Design: Existing Buildings: Not applicable.
For California compliance, construction assemblies for the proposed design shall be created by selecting from a library of building construction layers in ACM Appendix 5.5. The compliance software shall specify composite layers that consist of both framing and insulation. It shall use established methods defined in the ASHRAE Handbook of Fundamentals for calculating effective R-values of composite layers.
Geometry
The geometry of roofs, walls, floors, doors, and fenestration should match the construction documents or as-built drawings as accurately as possible. Unusual curved surfaces such as a dome or semi-circular wall may be approximated by a series of constructions.
Mass Walls
For mass walls, the user first chooses the mass layer from Appendix 5.5. After that, the user may select an insulating layer from Appendix 5.5 for outside and/or inside the mass wall.
Ballasted Roofs, Vegetated Roofs, Concrete Pavers, and Other Mass Roofs
An additional layer may be added to the roof construction assembly when thermal mass is used above the roof membrane. This exception is intended to allow ballasted roofs, concrete pavers, and other massive elements to be explicitly modeled. To qualify, the weight of the stone ballast, the concrete pavers or other elements must exceed 25 lb/ft². The thickness, heat capacity, conductance and density of the additional mass layer shall be based on the measured physical properties of the material. If the surface properties of the additional mass material have been verified through the Cool Roof Rating Council (CRRC), the CRRC reported properties may be used for the proposed design. Otherwise, the mass layer shall be modeled with an aged reflectance of 0.10 and an emittance of 0.75.
Assembly Name
Applicability: All projects.
Definition: The name of a construction assembly that describes a roof, wall, or floor assembly. The name generally needs to be unique so it can be referenced precisely by surfaces.
Units: Text.
Input Restrictions: Required input and name must be unique.
Standard Design: Not applicable.
Standard Design: Existing Buildings: Not applicable.
Specification Method
Applicability: All projects.
Definition: The method of describing a construction assembly. The common method is to describe the construction assembly as a series of layers, each layer representing a material. For slab-on-grade constructions, exterior insulation levels are specified, and the compliance software determines the corresponding F-factor from Reference Appendix JA4 tables.
Units: List: layers, F-factor.
Input Restrictions: The layers method shall be used for all above-grade constructions.
Standard Design: For each construction, the proposed design specification method shall be used.
Standard Design: Existing Buildings: Same as newly constructed buildings.
Layers
Applicability: All construction assemblies that use the layers method of specification
Definition: A structured list of material names that describe a construction assembly, beginning with the exterior finish and progressing through the assembly to the interior finish. Material names must be from the standard list (Appendix E) or defined (see above) ACM Appendix 5.5A.
Units: List: layers of construction assembly
Input Restrictions: The user is required to describe all layers in the actual assembly and model the proposed design based the layer descriptions.
Standard Design: See building descriptors for roofs, exterior walls, exterior floors, doors, fenestration, and below-grade walls.
Standard Design: Existing Buildings: Same as newly constructed buildings
Roof Name
Applicability: All roof surfaces.
Definition: A unique name or code that identifies the roof and ties it to the construction documents submitted for energy code review. It is not mandatory to name roofs.
Units: Text.
Input Restrictions: Name must be unique.
Standard Design: N/A.
Standard Design: Existing Buildings: N/A.
Roof Type
Applicability: All roof surfaces.
Definition: A roof classification defined in the Energy Code. This descriptor can be derived from other building descriptors and it may not be necessary for the compliance software user to specify it directly.
Units: List: metal building roofs, wood framed or other, residential or non-residential; steep or low-slope roof.
Input Restrictions: As designed for existing buildings.
Standard Design: All roofs in the standard design are modeled as wood-framed and other.
Standard Design: Existing Buildings: Same as proposed.
Roof Geometry
Applicability: All roofs.
Definition: Roof geometry defines the position, orientation, azimuth, tilt, and dimensions of the roof surface. The details of how the coordinate system is implemented may vary between compliance software programs. 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.
Standard Design: Roof geometry is identical in the proposed and standard design building designs.
Standard Design: Existing Buildings: Roof geometry will be identical in the proposed and standard design building designs. For alterations, roof geometry will be fixed, based on one of the building prototypes
Roof Solar Reflectance
Applicability: All opaque exterior roof surfaces exposed to ambient conditions.
Definition: The solar reflectance of a material. For roofing materials, the three-year aged reflectance value from CRRC testing should be used if available.
Units: Unitless.
Input Restrictions: Must be in the range of 0 to 1.
For roofs that are part of newly constructed buildings, if asphalt shingles or composition shingles are not rated by the CRRC, the default aged solar reflectance shall be equal to 0.08 for asphalt roofs and 0.10 for all other roof types. The default value may be overridden when roof materials are used that the CRRC has tested and are called for in the construction documents. In cases where the default value is overridden, the user is required to submit documentation identifying the test procedure that was used to establish the non-default values. If the aged CRRC reflectance is not known, the aged CRRC reflectance may be calculated from the initial CRRC reflectance using the following equation:
ƿaged = 0.2 + β · (ƿinit – 0.2)
Where,
ƿaged - the calculated aged reflectance
β - 0.65 for field-applied coatings, 0.7 for all other roof surfaces
ƿinit - the initial CRRC reflectance
As a compliance option, low-sloped roofs that use aggregate may specify an aged reflectance of 0.50 if the product meets the following criteria:
Conforms to material standard ASTM D1863.
Conforms to ASTM D448, size number equal between No.6 and No.7.
Has a CRRC‐tested initial solar reflectance that meets or exceeds 0.55 using the ASTM E1918 test procedure with aggregate passing a No. 4 sieve and is retained by a No. 8 sieve that conforms to ASTM D448, conducted by a CRRC-accredited independent laboratory meeting the requirement of §10‐113(d)4 of the Building Energy Efficiency Standards.
Has a label on bags or containers of aggregate stating that the materials conform to ASTM D1863 and ASTM D448.
Standard Design: For newly constructed buildings, the standard design reflectance is defined in Table 140.3-B for nonresidential buildings, Table 140.3-C for guest rooms of hotel/motel buildings containing guestrooms, Table 140.3-D for relocatable classroom buildings, and Table 170.2-A for multifamily buildings.
For alterations to more than 50 percent of the roof area or roof areas above 2,000 ft², the standard design shall be modeled as the more efficient of either the existing conditions or the values required for cool roofs under §141.0 and §180.2 of the Energy Code.
Standard Design: Existing Buildings: For alterations to more than 50 percent of the roof area or roof areas above 2,000 ft2, the standard design shall be modeled as the more efficient of either the existing conditions or the values required for cool roofs under §141.0 and §180.2.
Roof Thermal Emittance
Applicability: All opaque exterior roof surfaces exposed to ambient conditions.
Definition: The thermal emittance of a material. For roofing materials, the three-year aged emittance value from CRRC testing should be used if available.
Units: Unitless.
Input Restrictions: Must be in the range of 0 to 1.
For roofs, newly constructed buildings: as designed, from CRRC values. If CRRC rating information is not available, the default thermal emittance shall be 0.85. Aggregate that meets the following criteria may specify a thermal emittance of 0.85:
Conforms to material standard ASTM D1863.
Conforms to ASTM D448, size number equal between No.6 and No.7.
Has a CRRC‐tested initial solar reflectance that meets or exceeds 0.55 using the ASTM E1918 test procedure with aggregate passing a No. 4 sieve and is retained by a No. 8 sieve that conforms to ASTM D448, conducted by a CRRC accredited independent laboratory meeting the requirement of §10‐113(d) 4 of the Building Energy Efficiency Standards.
Has a label on bags or containers of aggregate stating that the materials conform to ASTM D1863 and ASTM D448.
Standard Design: For roofs, newly constructed buildings, the standard design thermal emittance shall be 0.75.
For alterations to more than 50 percent of the roof area or roof areas above 2,000 ft², the standard design shall be modeled as the more efficient of either the existing conditions or a thermal emittance of 0.85.
Standard Design: Existing Buildings: If the existing roof is unaltered, same as proposed. For alterations, the standard design is 0.85.
For alterations to more than 50 percent of the roof area or roof areas above 2,000 ft2, the standard design shall be modeled as the more efficient of either the existing conditions or a thermal emittance of 0.80.
Roof Construction
Applicability: All roofs.
Definition: A specification containing a series of layers that result in a construction assembly for the proposed design. The first layer in the series represents the outside (or exterior) layer and the last layer represents the inside (or interior) layer. See the building descriptors above for roof construction type.
Units: List: layers.
Input Restrictions: The area-weighted average of the roof construction assembly U-factors, defined by a series of layers, must be equal to or more efficient than the mandatory U-factor requirements of §120.7 and §160.1 of the Energy Code for newly constructed buildings, and §141.0 and §180.2 of the Energy Code for alterations. Note that these U-Factor requirements assume an exterior air film of R-0.17 and an interior air film of R-0.61. Each layer specified must be listed in the materials database in the ACM Appendix 5.5.
Newly constructed buildings
Metal Building: U – 0.098
Wood Framed and Others: U – 0.075
Additions and Alterations
Roof / Ceiling Insulation: See §141.0(b)2Biii and §180.2(b)2B of the Energy Code
Appropriate R-values for insulation can be calculated using the formula below.
Ceilings that form the boundary between the modeled building of an additions and alterations project and the existing, un-modeled portion of the building may be modeled as adiabatic roofs (no heat transfer).
Standard Design: Roofs in the standard design are of the type “insulation entirely above deck.” The insulation requirement is determined by climate zone. The standard design building roof construction shall be modeled as layers as defined. See Appendix 5.5for details.
For newly constructed buildings, the standard design roof type is wood framed and other, and the roof is a standing seam metal roof, with the R-value of continuous insulation adjusted to match the prescriptive standards for wood-framed and other roofs. The U-factor required for roof construction is defined in Table 140.3-B, 140.3-C, 140.3-D, or Table 170.2-A of the Energy Code. Programs that model a U-factor shall include an exterior and interior air film resistance. The standard design construction is based on JA4 Table 4.2.7 and assumes an exterior air film of R-0.17 and an interior air film of R-0.61.
The standard design construction shall include the following layers:
•Layer 1
o Metal Standing Seam 1/16 in.
o R - 0.00
•Layer 2
o Continuous Insulation
o R - Based on Climate Zone
•Layer 3
o Open Framing + No Insulation
o R - 0.00
The value of the continuous insulation layer entirely above framing shall be set to achieve the following R-values:
Nonresidential Buildings: Continuous Insulation
•Climate Zones 2, 3, 4, 9-16
o R - 28.63 (U-0.034)
•Climate Zones 1, 5
o R - 28.63 (U-0.034)
•Climate Zones 7, 8
o R - 19.62 (U-0.049)
•Climate Zones 6
o R - 19.62 (U-0.049)
Multifamily Buildings and Hotel/Motel Guestrooms: Continuous Insulation
•Climate Zones 1, 2,4,8-16
o R - 34.93 (U-0.028)
•Climate Zone 7
o R - 24.86 (U-0.039)
•Climate Zones 3, 5, 6
o R - 28.63 (U-0.034)
For mixed-use buildings, the roof standard design requirements shall be determined by which space type (nonresidential or residential) is the majority of the floor area of the adjoining conditioned spaces.
For re-locatable classroom buildings, the standard design shall use the construction assembly corresponding to the most stringent of requirements in any climate zone, or R-28.63 continuous insulation.
For alterations, any approved roof type may be used. The U-factor in the standard design shall be modeled as the more efficient of either the existing conditions or the values stated in §141.0 and §180.2 of the Energy Code. Where applicable, selection shall be based on building type, assembly, and climate zone. A construction of layers shall be defined to yield an equivalent U-factor.
Standard Design: Existing Buildings: For existing buildings, if the roof component is not altered, the standard design roof construction shall match the proposed design roof construction of the existing building. If the roof is altered, the roof component shall meet the prescriptive requirements for newly constructed buildings for the roof type of the existing building.
The roof type of the existing building is either a metal building roof or a wood-framed or other roof. The standard design roof assemblies for altered roofs are shown below for the appropriate climate zones.
Alterations Roof Standard Design:
For alterations, any approved roof type may be used. The U-factor in the standard design shall be modeled as the more efficient of either the existing conditions or the values stated in §141.0 and §180.2 of the Energy Code. Where applicable, selection shall be based on building type, assembly, and climate zone. A construction of layers shall be defined to yield an equivalent U-factor.
Wall Name
Applicability: All walls.
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.
Input Restrictions: Must be unique.
Standard Design: None.
Standard Design: Existing Buildings: None.
Applicability: All walls.
Definition: One of four categories of above-grade wall assemblies used to determine minimum insulation requirements for walls. The five wall type categories are as follows:
1. Mass Light
2. Mass Heavy
4. Metal framing
5. Wood framing and other walls
A mass light wall is defined as a wall with total heat capacity greater than 7 but less than 15 Btu/ft2-. A mass heavy wall is defined as a wall with a total heat capacity of 15 Btu/ft2-°F or greater. (Heat capacity is defined as the product of the specific heat in Btu/lb-°F, the thickness in ft, and the density in lb/ft3.)
Units: List: mass light, mass heavy, metal building walls, metal framing walls, and wood framing and other walls
Input Restrictions: This input is required for existing buildings when any wall is altered. This input is not required for newly constructed buildings.
Standard Design: All walls in the standard design building are modeled as “metal framed.”
Standard Design: Existing Buildings: Same as proposed.
Wall Geometry
Applicability: All walls
Definition: Wall geometry defines the position, orientation, azimuth, and tilt of the wall surface. The data structure for surfaces is described in the reference section of this chapter.
Units Data structure: surface
Input Restrictions: As designed
Standard Design: Same as proposed
Standard Design: Existing Buildings: Same as proposed
Wall Fire Rating
Applicability: All walls in multifamily buildings.
Definition: The fire rating for the exterior walls in the building.
Units: hr (integer – typically, 1 hr, 2 hr).
Input Restrictions: This input is required for existing buildings when any wall is altered. This input is not required for newly constructed buildings.
Standard Design: Not required.
Standard Design: Existing Buildings: Same as proposed.
Wall Solar Reflectance
Applicability: All opaque exterior walls exposed to ambient conditions.
Definition: The solar reflectance of a material.
Units: Unitless ratio.
Input Restrictions: For walls and other non-roof surfaces, the value is prescribed to be 0.3.
Standard Design: For walls and other non-roof surfaces, the value is prescribed to be 0.3.
Standard Design: Existing Buildings: 0.3.
Wall Thermal Emittance
Applicability: All opaque exterior walls exposed to ambient conditions.
Definition: The thermal emittance of a material.
Units Unitless ratio.
Input Restrictions: For walls and other non-roof surfaces, the value is prescribed to be 0.9.
Standard Design: For walls and other non-roof surfaces, the thermal emittance is 0.9.
Standard Design: Existing Buildings: For walls and other non-roof surfaces, the thermal emittance is 0.9.
Wall Construction
Applicability: All walls that use the layers method.
Definition: A specification containing a series of layers that result in a construction assembly for the proposed design. The first layer in the series represents the outside (or exterior) layer and the last layer represents the inside (or interior) layer. See the building descriptors above for wall construction type.
Units: List: Layers.
Input Restrictions: The area weighted-average of the construction assembly U-factors, defined by a series of layers, must be equal to or more efficient than the mandatory U-factor requirements of §120.7 and §160.1 of the Energy Code for newly constructed buildings. Note that these U-Factor requirements assume an exterior air film of R-0.17 and an interior air film of R-0.68. Each layer specified, with the exception of composite layers, must be listed in the materials database in the ACM Appendix 5.5A.
Newly Constructed
•Metal Building
o U – 0.113
•Metal Framed
o U – 0.151 (R-13 cavity + R-2 continuous insulation, or equivalent)
•Light Mass Walls
o U – 0.440
•Heavy Mass Walls
o U – 0.690
•Wood Framed and Others
o U – 0.110
•Spandrel Panels / Glass Curtain Walls
o U – 0.280
Additions and Alterations
•Metal Building
o U – 0.113
•Metal Framed
o U – 0.217
•Wood Framed and Others
o U – 0.110
•Spandrel Panels / Glass Curtain Walls
o U – 0.280
Appropriate R-values for insulation can be calculated using the formula below.
Walls that form the boundary between the modeled building of an additions and alterations project and the existing, un-modeled portion of the building may be modeled as adiabatic walls (no heat transfer).
Standard Design: The U-factor required for wall construction of the standard design building is defined in Table 140.3-B, 140.3-C, 140.3-D, or 170.2-A of the Energy Code. Programs that model a U-factor shall use an exterior and interior air film resistance. The standard design construction is based on JA4 Table 4.3.3 and assumes an exterior air film of R-0.17 and an interior air film of R-0.68.
For metal framed walls, the standard design construction shall include the following layers:
•Layer 1
o Stucco – 7/8 in.
o R - 0.18
•Layer 2
o Building Paper
o R – 0.06
•Layer 3
o Continuous Insulation
o R - Based on Climate Zone
•Layer 4
o Closed Framing and No Ins.
o R – 0.65
•Layer 5
o Gypsum Board – 1/2 in.
o R – 0.45
Standard Design: Existing Buildings: The value of the continuous insulation layer entirely outside framing shall be set to achieve the following R-values:
Nonresidential Buildings: Continuous Insulation
•Climate Zones 1, 6, and 7
o R – 14.47
•Climate Zones 2, 4, 5, and 8 – 16
o R – 15.99
•Climate Zone 3
o R – 11.90
Multifamily Buildings and Hotel/Motel Guestrooms: Continuous Insulation
•Climate Zones 1 - 6, and 8-16
o R – 12.30
•Climate Zone 7
o R – 7.33
For mixed-use buildings that contain both nonresidential and residential spaces, walls adjacent to nonresidential spaces shall use the Nonresidential Buildings standard design construction, and walls adjacent to residential and multifamily spaces shall use the multifamily standard design construction.
For relocatable classroom buildings, the standard design shall use the construction assembly corresponding to the most stringent of requirements in any climate zone, or R-13.94 continuous insulation.
|
CZ2,10-16 |
CZ 1 |
CZ 4 |
CZ 3 |
CZ 5-9 | |
|
JA4 U-factor |
0.170 |
0.196 |
0.227 |
0.278 |
0.440 |
|
Layer 1 |
4 in MW CMU, 115 lb/sf 4.3.6-B5 |
4 in MW CMU, 115 lb/sf 4.3.6-B5 |
4 in MW CMU, 115 lb/sf 4.3.6-B5 |
4 in MW CMU, 115 lb/sf 4.3.6-B5 |
8 in NW CMU, 125 lb/ft2, partly grouted, reinforced with insulated cells 4.3.6-C10 |
|
Layer 2* |
3” furring space with R-21 insulation and metal clips 4.3.14-V15 (equiv R-4.8 c.i.) |
2.5” furring space with R-13 insulation and metal clips 4.3.14-R13 (equiv R-3.8 c.i.) |
2” furring space with R-13 insulation and metal clips 4.3.14-N11 (equiv R-3.3 c.i.) |
1.5” furring space with R-9 insulation and metal clips 4.3.14-J9 (equiv R-2.5 c.i.) |
N/A |
|
Layer 3 |
|
|
|
|
|
|
… |
N/A |
N/A |
N/A |
N/A |
N/A |
|
Layer n |
N/A |
N/A |
N/A |
N/A |
N/A |
Source: California Energy Commission
Table 6 Heavy Mass Wall (Heat Capacity >= 15 Btu/ft2-F)
|
CZ2,10-16 |
CZ 1 |
CZ 4 |
CZ 3 |
CZ 5-9 |
||
|
JA4 U-factor |
0.160 |
0.184 |
0.211 |
0.253 |
0.650 |
0.690 |
|
Layer 1 |
8 in. NW CMU, 125 lb/ft2, solid grout, reinforced 4.3.5-A10 |
8 in. NW CMU, 125 lb/ft2, solid grout, reinforced 4.3.5-A10 |
8 in. NW CMU, 125 lb/ft2, solid grout, reinforced 4.3.5-A10 |
8 in. NW CMU, 125 lb/ft2, solid grout, reinforced 4.3.5-A10 |
8 in. NW CMU, 125 lb/ft2, solid grout, reinforced 4.3.5-A9 |
8 in. NW CMU, 125 lb/ft2, solid grout, reinforced 4.3.5-A10 |
|
Layer 2* |
3” furring space with R-21 insulation and metal clips 4.3.14-V15 (equiv R-4.8 c.i.) |
2.5” furring space with R-13 insulation and metal clips 4.3.14-R13 (equiv R-3.8 c.i.) |
2” furring space with R-13 insulation and metal clips 4.3.14-N11 (equiv R-3.3 c.i.) |
1.5” furring space with R-9 insulation and metal clips 4.3.14-J9 (equiv R-2.5 c.i.) |
N/A |
N/A |
|
Layer 3 |
N/A |
N/A |
N/A |
N/A |
N/A |
N/A |
|
|
N/A |
N/A |
N/A |
N/A |
N/A |
N/A |
|
Layer n |
N/A |
N/A |
N/A |
N/A |
N/A |
N/A |
Source: California Energy Commission
Table 7 Metal Building Walls
|
CZ15 |
CZ 2,4,5,8,9,10-14,16 |
CZ 1,3,6,7 | |
|
JA4 U-factor |
0.057 |
0.061 |
0.113 |
|
Layer 1 |
R-13 batt insulation draped over purlins and compressed |
Layer 1 |
R-13 batt insulation draped over purlins and compressed |
|
Layer 2* |
Second layer R-13 batt insulation |
Second layer R-10 batt insulation |
N/A |
|
Layer 3 |
N/A |
N/A |
N/A |
|
… |
N/A |
N/A |
N/A |
|
Layer n |
N/A |
N/A |
N/A |
Source: California Energy Commission
Table 8 Wood-Framed Walls
|
CZ15 |
CZ 2,4,9-14,16 |
CZ 4 |
CZ 3 | |
|
JA4 U-factor |
0.042 |
0.059 |
0.102 |
0.110 |
|
Layer 1 |
2x4, 16” o.c, with R-13 batt ins |
2x4, 16” o.c., with R-11 batt ins |
2x4, 16” o.c. with R-13 batt ins |
2x4, 16” o.c. with R-11 batt ins |
|
Layer 2* |
R-14 continuous insulation |
R-8 continuous insulation |
N/A |
N/A |
Source: California Energy CommissionFloor Name
Floor Name
Applicability: All floor surfaces.
Definition: A unique name or code that relates the exposed floor to the design documents.
Exposed floors include floors exposed to the outdoors and floors over unconditioned spaces, but do not include slab-on-grade floors, below grade floors, or interior floors.
Units: Text.
Input Restrictions: Must be unique.
Standard Design: None.
Standard Design: Existing Buildings: None.
Floor Type
Applicability: All exterior floor surfaces, optional.
Definition: The category that defines the standard design prescriptive floor requirements.
Units: List: mass or other.
Input Restrictions:
Standard Design: The standard design building floors shall be of type “other”.
Standard Design: Existing Buildings: Same as proposed.
Floor Geometry
Applicability: All exterior floors.
Definition: Floor geometry defines the position, orientation, azimuth, and tilt of the floor surface. The details of how the coordinate system is implemented may vary between compliance software programs. The data structure for surfaces is described in the reference section of this chapter.
Units: Data structure: surface.
Input Restrictions: As designed. Required input.
Standard Design: Standard design building floor geometry is identical to the proposed design.
Standard Design: Existing Buildings: Same as proposed.
Floor Construction
Applicability: All floors.
Definition: A specification containing a series of layers that result in a construction assembly for the proposed design. The first layer in the series represents the outside (or exterior) layer and the last layer represents the inside (or interior) layer. See the building descriptors above for floor construction type.
Units: List: Layers.
Input Restrictions: The area weighted-average of the floor construction assembly U-factors, defined by a series of layers, must be equal to or more efficient than the mandatory U-factor requirements of §120.7 and §160.1 of the Energy Code for newly constructed buildings, and §141.0 and §180.2 of the Energy Code for alterations. Note that these U-factor requirements assume an exterior air film of R-0.17 and an interior air film of R-0.92. Each layer specified must be listed in the materials database in the ACM Appendix 5.5A.
Newly constructed buildings
•Raised Mass Floors
o U – 0.269
•Other Floors
o U – 0.071
•Heated Slab Floors
o Climate Zone (see §120.7 and §160.1)
Additions and Alterations
o U – 0.113
•Metal Framed
o U – 0.217
•Wood Framed and Others
o U – 0.110
•Spandrel Panels / Glass Curtain Walls
o U – 0.280
Appropriate R-values for insulation can be calculated using the formula below.
Floors that form the boundary between the modeled building of an addition and alteration project and the existing, un-modeled portion of the building may be modeled as adiabatic floors (no heat transfer).
Standard Design: The U-factor required for floor construction is defined in Table 140.3-B, 140.3-C, 140.3-D, or 170.2-A of the Energy Code. Programs that model a U-factor shall use an exterior and interior air film resistance. The standard design construction is based on JA4 Table 4.4.5 and assumes an exterior air film of R-0.17 and an interior air film of R-0.92.
For metal framed floors, the standard design construction shall include the following layers:
•Layer 1
o Open Framing + No Ins.
o R – 0.00
•Layer 2
o Continuous Insulation
o R – Based on Climate Zone
•Layer 3
o Plywood – 5/8 in.
o R – 0.78
•Layer 4
o Carpet and Pad – 3/4 in.
o R – 1.30
Standard Design: Existing Buildings: The value of the continuous insulation layer entirely above or below framing shall be set to achieve the following R-values:
Nonresidential Buildings: Continuous Insulation
o R – 17.66
•Climate Zones 2, 11, and 14 -16
o R – 22.47
•Climate Zones 3 – 10, 12, and 13
o R – 10.91
Multifamily Buildings and Hotel/Motel Guestrooms: Continuous Insulation
•Climate Zones 1, 2, 14, and 16
o R – 26.24
•Climate Zones 3 – 6, 8 – 13, and 15
o R – 22.47
•Climate Zones 7
o R – 10.91
The standard design floor that serves as the boundary between the modeled additions and alterations building and the existing, unmodeled portion of the building is modeled as an adiabatic floor, to match the proposed design. The standard design floor construction for existing buildings depends on the floor type.
Raised Floors, Floor Type = Other (framed floors)
|
|
All Climate Zones, Nonres |
|
JA4 U-factor |
0.071, JA4 4.4.2-A2 |
|
Layer 1 |
2x6 Wood-Framed, 16” o.c., R-11 batt |
|
Layer 2 |
|
Source: California Energy Commission
Raised Floors, Floor Type= Mass
|
|
All Climate Zones, Nonres |
All Climate Zones, High-Rise Res. |
|
JA4 U-factor |
U=0.269 |
U=0.111, JA4 4.4.2-A2 |
|
Layer 1 |
Metal Deck, R-0 |
Metal Deck, R-0 |
|
Layer 2 |
4” Lightweight Concrete |
4” Lightweight Concrete |
|
Layer 3 |
|
R-6 continuous insulation |
Source: California Energy Commission
Door Name
Applicability All exterior doors, optional input.
Definition A unique name or code that relates the door to the design documents submitted. Doors that are more than 50 percent glass are treated as windows and must be determined and entered by using the Fenestration building descriptors.
Units: Text: unique.
Input Restrictions: None.
Standard Design: None.
Standard Design: Existing Buildings: None.
Door Type
Applicability: All exterior doors, required input.
Definition: One of two door classifications of either: swinging or non-swinging. Non-swinging are generally roll-up doors. The prescriptive U-factor requirements depend on door type and climate. This building descriptor may be derived from other building descriptors, in which case a specific input is not necessary.
Units: List: swinging or non-swinging.
Input Restrictions: The door type shall be consistent with the type of door represented on the construction documents or as-built drawings.
Standard Design: The standard design building door type shall be the same as the proposed design.
Standard Design: Existing Buildings: Same as newly constructed buildings.
Door Geometry
Applicability: All exterior doors.
Definition: Door geometry defines the position and dimensions of the door surface relative to its parent wall surface. The azimuth and tilt (if any) of the door is inherited from the parent surface. The position of the door within the parent surface is specified through (X, Y) coordinates. The size is specified as a height and width (all doors are generally assumed to be rectangular in shape). The details of how the geometry of doors is specified may vary for each energy simulation program.
Units: Data structure: opening.
Input Restrictions: As designed.
Standard Design: Door geometry in the standard design building is identical to the proposed design.
Standard Design: Existing Buildings: Same as newly constructed buildings.
Door Construction
Applicability: All exterior doors.
Definition: The thermal transmittance of the door, including the frame.
Units: Btu/h·ft2·°F.
Input Restrictions: The construction assembly must be equal to or more efficient than the mandatory U-factor requirements of §110.6 of the Energy Code for newly constructed buildings. There are no restrictions for alterations.
Standard Design: For newly constructed buildings, the U-factor required for door construction is defined in Table 140.3-B, 140.3-C, 140.3-D, or 170.2-A of the Energy Code.
Nonresidential Buildings – U Factor:
Non-Swinging Doors:
•Climate Zones 1, and 16
o U – 0.50
•Climate Zones 2 – 15
o U – 1.45
Swinging Doors:
•Climate Zones 1 – 16
o U – 0.70
Multifamily Buildings and Hotel/Motel Guestrooms – U Factor:
Non-Swinging Doors:
•Climate Zones 1, and 16
o U – 0.50
•Climate Zones 2 – 15
o U – 1.45
Swinging Doors:
•Climate Zones 1 – 16
o U – 0.70
Standard Design: Existing Buildings: For alterations, the U-factor in the standard design is either the same standard design as the newly constructed buildings standard design if the door is replaced, or the equal to the existing door construction, if the door is unaltered. Where applicable, selection shall be based on building type, assembly, and climate zone.
Operable Door Opening Type
Applicability: All exterior doors.
Definition: The opening type that determines whether interlocks with mechanical cooling and heating are required, per §140.4(n) and §170.2(c)4L. If manual, then interlocks are required when operable windows are present in any nonresidential space, excluding multifamily and healthcare spaces and buildings. If self-closing or a glazed door, interlocks are not required and are not present in the standard design.
Units Btu/h·ft2·°F.
Input Restrictions: List: Self-Closing, Manual, Glazed Door.
Standard Design: Same as Proposed.
Note that fenestration includes windows, doors that have 25 percent or more glazed area, and skylights. A skylight is fenestration that has a tilt of less than 60 degrees from horizontal.
Fenestration Name
Applicability: All fenestration, optional input.
Definition: A unique name or code that relates the fenestration to the design documents and a parent surface.
Units: Text: unique.
Input Restrictions: None.
Standard Design: None.
Standard Design: Existing Buildings: None.
Fenestration Type (Vertical Fenestration)
Applicability: All vertical fenestration.
Definition: This is a classification of vertical fenestration that determines the thermal performance and solar performance requirement for vertical fenestration.
Units: List: Fixed, Operable, Curtain Wall, Glazed Doors.
Input Restrictions: As designed
Standard Design: Same as the proposed design
Standard Design: Existing Buildings: Same as newly constructed buildings
Fenestration Type (Skylights)
Applicability: All skylights
Definition: This is a classification of skylights that determines the thermal performance and solar performance requirement for vertical fenestration
Units List: Glass, Curb-mounted, Glass, Deck-mounted, or Plastic.
Input Restrictions: As designed
Standard Design: Same as the proposed design
Standard Design: Existing Buildings: Same as newly constructed buildings
Default Fenestration Type
Applicability: All fenestration that uses default thermal performance factors
Definition: This is a classification of fenestration that determines the thermal performance for fenestration using defaults from the Energy Code § 110.6, Table 110.6-A. This is used for fenestration without National Fenestration Rating Council (NFRC) ratings or for fenestration for altered buildings that includes window films.
Units : List: fixed, operable, greenhouse/garden, doors, or skylight
Input Restrictions: As designed. The default value shall be fixed.
Standard Design: Not applicable
Default Glazing Type
Applicability: All fenestration that uses default thermal performance factors
Definition: This is a classification of fenestration that determines the thermal performance for fenestration using defaults from the Energy Code § 110.6, Table 110.6-A. This is used for fenestration without NFRC ratings or for fenestration for altered buildings that includes window films.
Units: List: single pane, double pane, glass block
Input Restrictions: As designed. The default value shall be single-pane.
Glass block is only allowed if the default fenestration type is operable or fixed.
Standard Design: Not applicable
Default Framing Type
Applicability: All fenestration that uses default thermal performance factors.
Definition: This is a classification of fenestration that determines the thermal performance for fenestration using defaults from the Energy Code § 110.6, Table 110.6-A. This is used for fenestration without NFRC ratings or for fenestration for altered buildings that includes window films.This is also used for skylight products where the thermal performance is determined by the equations from the Reference Appendix NA6.
Units: List: metal, metal with thermal break, or nonmetal.
Input Restrictions: As designed. The default value shall be metal.
Standard Design: Not applicable.
DEFAULT DIVIDER TYPE
Applicability: All double-pane fenestration that uses default thermal performance factors.
Definition: This is a classification of fenestration that determines the thermal performance for fenestration using defaults from the Energy Code § 110.6, Table 110.6-A. This is used for fenestration without NFRC ratings or for fenestration for altered buildings that includes window films.
Units: List: no divider, true divided lite, divider between panes less than 7/16 inch, or divider between panes greater than or equal to 7/16 inch.
Input Restrictions: As designed. The default value shall be no divider.
Standard Design: Not applicable.
DEFAULT TINT TYPE
Applicability: All fenestration that uses default thermal performance factors.
Definition: This is a classification of fenestration that determines the thermal performance for fenestration using defaults from the Energy Code § 110.6, Table 110.6-B. This is used for fenestration without NFRC ratings or for fenestration for altered buildings that includes window films.
Units: List: clear glazing, tinted glazing.
Input Restrictions: As designed. The default value shall be clear.
Standard Design: Not applicable.
DEFAULT OPERABLE CONFIGURATION
Applicability: All operable fenestration that uses default thermal performance factors.
Definition: This is a classification of fenestration that determines the visible transmittance (VT) for fenestration using defaults from the Energy Code Appendix NA6. This is used for fenestration without NFRC ratings, for fenestration for altered buildings that includes window films, or skylights.
Units: List: casement or awning, sliding.
Input Restrictions: As designed. The default value shall be sliding.
Standard Design: Not applicable.
Fenestration Geometry
Applicability: All fenestration.
Definition: Fenestration geometry defines the position and dimensions of the fenestration surface within its parent surface and the identification of the parent surface. The orientation and tilt are inherited from the parent surface. The details of how the coordinate system is implemented may vary between compliance software programs.
Display perimeter is the length of an exterior wall in a B-2 occupancy that immediately abuts a public sidewalk, measured at the sidewalk level for each story that abuts a public sidewalk. The compliance software shall allow the user to specify a value for the length of display perimeter, in feet, for each floor or story of the building. The user entry for display perimeter shall have a default value of zero. Note: Any non-zero input for display perimeter is an exceptional condition that shall be reported on the PRF-1 exceptional condition list and shall be reported on the ENV forms. The value for display perimeter is used as an alternate means of establishing maximum wall fenestration area in the standard design (§140.3 of the Energy Code).
The display perimeter shall be calculated separately for west-facing fenestration, and for non-west facing fenestration.
Floor Number:
The compliance software shall also allow the user to specify the display perimeter associated with each floor (story) of the building.
Units: Data structure: opening
Geometry is defined relative to the parent surface and can include setbacks.
Inputs include:
Geometry of opening (window or skylight), parent surface, display perimeter (optional), percent of roof area exempt from skylight requirements §140.3 of the Energy Code.
Input Restrictions: As designed
Specification of the fenestration position within its parent surface is required for the following conditions:
Exterior shading is modeled from buildings, vegetation, or other objects; or
If daylighting is modeled within the adjacent space.
Standard Design: The standard design calculates the window wall ratio (WWR) for each orientation and the overall window wall ratio for the building. The window wall ratio is the total fenestration area (including framing) divided by the gross exterior wall area (excluding wall area that is underground). Note that exterior wall area that is below grade, but has exposure to ambient conditions, and any associated fenestration, is included in the WWR calculation.
The standard design vertical fenestration area and horizontal fenestration area for spaces that are specified as computer rooms or data centers (a server process load of 20W/ft2 or higher) shall be zero.
For all other buildings, the geometry of the fenestration in the standard design shall be identical to the proposed design with the following exceptions:
Exception 1: Either the whole building window wall ratio or west window wall ratio exceeds 40 percent.
Exception 2: If display perimeter is entered, the fenestration area exceeds the greater of 40 percent of the gross wall area (excluding adiabatic walls) and six times the display perimeter.
Exception 1: The fenestration is adjusted based on the following conditions:
Case 1. WWRo > 0.40, WWRw ≤0.40
In this case, the fenestration area of all windows is reduced by multiplying the fenestration area by the ratio 0.40/WWRo. The dimensions of each window are reduced by increasing the sill height so that the window height is modified by the multiplier (0.40/WWRo) so that the same window width is maintained.
Case 2: WWRo < 0.40. WWRw > 0.40
In this case, the fenestration area of all windows on the west orientation is reduced by multiplying the fenestration area by the ratio 0.40/WWRo. The dimensions of each window are reduced by multiplying the proposed window dimension by increasing the sill height so that the window height is modified by the multiplier (0.40/WWRo), so that the window width is maintained.
Case 3: WWRo > 0.40. WWRw > 0.40
If both the west window wall ratio and the overall window wall ratio exceed the prescriptive limit of 0.40, the fenestration areas must be reduced by:
Ø Adjust the west window area multiplying the west window area by the ratio 0.4/WWRw.
Ø Calculate the WWR of the north, east and south facades:
Ø WWRnes = Window Areanes / Gross Wall Areanes
Ø Adjust the window area of the windows on the north, east and south facades by the following ratio:
WindowAreaN,std = WindowAreaN,prop × 0.4 / WWRnes
WindowAreaE,std = WindowAreaE,prop × 0.4 / WWRnes
WindowAreaS,std = WindowAreaS,prop × 0.4 / WWRnes
Adjust each window geometry for the west façade by multiplying the window height by (0.4/WWRw) by adjusting the sill height and by maintaining the same window width.
Adjust each window geometry for the north, east and south façade by multiplying the window height by (0.4/WWRnes) by adjusting the sill height and by maintaining the same window width.
Exception 2: If the display perimeter is entered and the window area exceeds the prescriptive limit, the window area for the standard design is calculated by multiplying the proposed window area by the following ratio:
WindowAreastd = 6 x DisplayPerimeter
The geometry of each window is modified by the following, and by modifying the sill height but not the head height position relative to the floor:
WindowHeightstd = WindowHeightprop x (WindowAreastd/WindowAreaprop)
WindowWidthstd = WindowWidthprop
The following rules apply for calculating geometry of skylights. For the calculation of the standard design skylight area, the gross roof area is defined as the total roof area, including skylights, that is directly over conditioned space.
The skylight area of the standard design is set:
Ø For buildings without atria or with atria having a height less than 55 feet over conditioned space, the smaller of the proposed skylight area and 5 percent of the gross roof area that is over conditioned space.
Ø For buildings with atria at a height of 55 ft or greater over conditioned spaces, the smaller of the proposed skylight area and 10 percent of the gross roof area that is over conditioned space.
Ø For buildings with atria or other roof area directly over unconditioned spaces, the smaller of the proposed skylight area or 5 percent of the roof area excluding the atria area and excluding any adiabatic walls, if present in the modeled building. The skylight area of the atria or roof area directly over unconditioned space is not included in the skylight area limit in this case.
The skylight area for atria over unconditioned space is not included in determining the skylight to roof ratio (SRR) for the building.
Depending on the following condition, adjustments to the SRR as described shall be made.
Ø For open spaces other than auditoriums, churches, movie theaters, museums and refrigerated warehouses, for buildings in climate zones 2 through 15, and when spaces have ceiling heights greater than 15 ft and floor areas greater than 5000 ft2, the skylight area shall be the greater of 3 percent or the area required to provide daylight coverage through skylights or primary side lighting to 75 percent of the floor area in the space. See 5.4.5 for detail description on primary daylit area and skylit daylit area.
Ø If the above condition is met and SRR ≤ 0.05, no adjustments are needed.
Ø If the condition is met and SRR > 0.05, skylight dimensions = Existing Dimension x [1- √ (0.05/SRR of Proposed Building)]
Ø If the condition is not met triggering the need for additional skylights, the standard design case shall be modeled with new skylights irrespective of the skylight location of the proposed case. The new skylights shall be distributed uniformly such that there is no overlapping of primary daylit areas from skylights or sidelights. The dimension of the new skylights shall be the same as the proposed design if calculated new SRR ≤ 0.05. If SRR > 0.05, skylight dimensions = existing dimension x [1- √ (0.05/SRR of proposed building)].
Note that the adjustments to SRR are done after adjustments to WWR if any are completed.
For compliance software that cannot make the adjustments described above, the compliance software should enforce the proposed design to provide daylight coverage using skylights or primary side lighting to 75 percent of the space floor area.
Standard Design: Existing Buildings: For alterations of existing vertical fenestration or skylights, where no fenestration area is added, the fenestration geometry of the standard design shall be the same as the proposed for the existing building.
For additions of vertical fenestration or skylights, where the additional fenestration causes the fenestration area to exceed the limit of 40 percent window to wall ratio (WWR) for the building, 40 percent WWR for the west orientation of the building, 5 percent skylight to roof ratio (SRR) for existing buildings without atria 55 feet or higher, or 10 percent SRR for existing buildings with atria 55 feet or higher, the fenestration geometry for the standard design shall be adjusted from the proposed design according to the rules set forth under the standard design rules.
For additions of vertical fenestration and/or skylights, where the existing fenestration already exceeds any of these limits, the new fenestration shall be removed.
For additions of vertical fenestration and/or skylights that do not cause the fenestration area to exceed any of these limits, the fenestration geometry of the standard design shall be the same as the proposed design.
Skylight Requirement Exception Fraction
Applicability: All buildings with interior ceiling heights greater than 15 feet.
Definition: The fraction of floor area that is exempt from the minimum skylight area requirement for spaces with high ceilings.
Identifying areas subject to §140.3 of the Energy Code:
When a proposed space has ceiling heights greater than 15 ft, with exterior surfaces having a tilt angle less than 60 degrees (roofs) and no more than three stories above grade, the user shall enter the fraction of the modeled space that is exempt from requirements of §140.3 of the Energy Code. If the proposed design has skylights, the user shall also indicate the area of the proposed design daylight area under skylights in this space. When the user enters a value greater than zero percent for the fraction of the space area exempt to §140.3 of the Energy Code, the compliance software shall require that the user indicate at least one of the following exceptions:
Ø The building is not located in climate zone 1 or climate zone 16
Ø Designed general lighting is less than 0.5 W/ft2
Ø Existing walls on plans result in enclosed spaces less than 5,000 ft2
Ø Future walls or ceilings on plans result in enclosed spaces less than 5,000 ft2 or ceiling heights less than 15 ft
Ø Plans or documents show that space is an auditorium, religious building of worship, movie theater, museum, or refrigerated warehouses
Units: Unitless fraction of area.
Input Restrictions: Must be in the range of 0 to 1 and should match the as-built drawings.
Standard Design: Same as the proposed design.
Standard Design: Existing Buildings: Not applicable.
Fenestration Construction
Applicability: All fenestration.
Definition: A collection of values that together describe the performance of a fenestration system.
The values that are used to specify the criteria are U-factor, SHGC, and VT. U-factor and SHGC inputs are whole-window values.
Units: Data structure: shall include at a minimum the following properties as specified by NFRC ratings:
U-factor: whole window U-factor (Btu/h ft2 °F).
SHGC: whole window solar heat gain coefficient (unitless)
VT: visible transmittance (unitless).
Input Restrictions: For newly constructed buildings, performance information for fenestration shall be obtained from NFRC test results or shall be developed from procedures outlined in §110.6 of the Energy Code, as specified below. Values entered shall be consistent with the specifications and the construction documents.
For manufactured products:
Ø U-factor, SHGC, and VT shall be equivalent to NFRC rated values.
For products not rated by NFRC, U-factor, SHGC and VT shall be determined from CEC default tables (110.6 A and B).
For site-built products:
Ø U-factor, SHGC, and VT shall be equivalent to NFRC rated values.
Ø For products not rated by NFRC, up to 200 ft2 of skylight area and alteration to vertical fenestration may use center of glass properties and Reference Appendix NA6 equations to calculate U-factor, SHGC, and VT. Any site-built fenestration in excess of 200 ft2 must use the default values in Table 110.6-A and 110.6-B.
For buildings with fenestration area that meets requirements for use of center-of-glass U-factor and SHGC, the fenestration overall U-factor, SHGC, and VT shall be determined by the following equations from the Reference Appendix NA6:
UT = C1 + (C2 · Uc)
SHGCT = 0.08 + (0.86 · SHGCc)
VTT = VTF · VTC
Where,
Ø UT - U-factor is the total performance of the fenestration including glass and frame
Ø C1 - Coefficient selected from Table NA6-5 in Reference Appendix NA6
Ø C2 - Coefficient selected from Table NA6-5 in Reference Appendix NA6
Ø UC - Center of glass U-factor calculated in accordance with NFRC 100 Section 4.5.3.1
Ø SHGCT - Total SHGC performance including glass and frame SHGCC = Center of glass SHGC calculated in accordance with NFRC 200 Section 4.5.1.1
Ø VTT - Is the total performance of the fenestration including glass and frame
Ø VTF - 0.53 for projecting windows, such as casement and awning windows
Ø VTF - 0.67 for operable or sliding windows
Ø VTF - 0.77 for fixed or non-operable windows
Ø VTF - 0.88 for curtain wall/storefront, site-built and manufactured non-curb mounted skylights
Ø VTF - 1.0 for curb mounted manufactured skylights
Ø VTC - Center of glass VT is calculated in accordance with NFRC 200 Section 4.5.1.1 or NFRC 202 for Translucent Products or NFRC 203 for Tubular Daylighting Devices and Hybrid Tubular Daylighting Devices or ASTM E972
For skylights, the default values shall be the alternate default U-factor and SHGC using default calculations specified above and in Reference Appendix NA6 or the U-factor and SHGC listed in Table 110.6-A and Table 110.6-B in the Energy Code.
Standard Design: For newly constructed buildings, the requirements for vertical fenestration U factor, SHGC, and visible light transmission by window or skylight type and framing type are specified in Table 140.3-B, C, or D of the Energy Code. For plastic skylights, SHGC of 0.50 is assumed.
Standard Design: Existing Buildings: The U-factor, SHGC, and VT in the standard design shall be modeled as design if unchanged, as the values stated in Table 141.0-A of the Energy Code when the existing window area is unchanged (different than the newly constructed buildings performance requirement), or Table 140.3-B, C, or D of the Energy Code for all other cases.
The standard design does not include window films.
External Shading Devices
Applicability: All fenestration.
Definition: Devices or building features that are documented in the construction documents and shade the glazing, such as overhangs, fins, shading screens, and setbacks of windows from the exterior face of the wall.
The Title 24 compliance software shall be capable of modeling vertical fins, horizontal slats, and overhangs. Recessed windows may also be modeled with side fins, horizontal slats, and overhangs.
Units: Data structure: surface.
Input Restrictions: No restrictions other than that the inputs must match the construction documents.
Standard Design: The standard design building is modeled without external shading devices.
Standard Design: Existing Buildings: No shading devices.
Internal Shading Devices
Applicability: All fenestration.
Definition: Curtains, blinds, louvers, or other devices that are applied on the room side of the glazing material.
Glazing systems that use blinds between the glazing layers are also considered internal shading devices. Glass coatings, components, or treatments of the glazing materials are addressed through the fenestration construction building descriptor.
Units: Not applicable – not modeled for compliance.
Input Restrictions: Not applicable – interior shading is not modeled for compliance.
Standard Design: Not applicable – interior shading is not modeled for compliance.
Standard Design: Existing Buildings: No interior shades.
Dynamic Glazing Present
Applicability: All fenestration that has dynamic glazing.
Definition: This is a flag used for reporting purposes only. Dynamic glazing is not modeled directly in compliance software.
Units: Boolean.
Input Restrictions: None.
Standard Design: False (not present).
Standard Design: Existing Buildings: Not Applicable.
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.
Standard Design: Not applicable.
Standard Design: Existing Buildings: Same as proposed.
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: As designed.
Standard Design: The geometry of below-grade walls in the standard design building is identical to the below-grade walls in the proposed design.
Standard Design: Existing Buildings: Same as proposed.
Below-Grade Wall Construction
Applicability: All projects, required input.
Definition: A specification containing a series of layers that result in a construction assembly for the proposed design. The first layer in the series represents the outside (or exterior) layer and the last layer represents the inside (or interior) layer. See the building descriptors above for below-grade wall construction type.
Units: Data structure: construction assembly.
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.
Input Restrictions: The construction assembly, defined by a series of layers, must be equal to or more efficient than the mandatory R-value and C-factor requirements of §120.7 of the Energy Code for newly constructed buildings, and §141.0 of the Energy Code for alterations. Note that these requirements only apply when the slab floor connected to the below-grade wall is heated.
For newly constructed buildings, the inputs shall agree with the construction documents. Values for the C-factor shall be taken from Table 4.3.5, 4.3.6, or 4.3.7 of Reference Appendix JA4.
For alterations there are no restrictions.
Standard Design: For newly constructed buildings, see Table 13. The standard design building shall use default values for C-factor. The height shall be the same as specified in the proposed design.
For below-grade walls, the standard design construction shall include the layers described in Appendix 5.7 and in the table below.
For alterations, the C-factor in the standard design shall be modeled as the more efficient of either the existing conditions, or the values stated above for newly constructed buildings standard design.
For below-grade walls, the alteration standard design assembly shall include the appropriate existing layers.
Standard Design: Existing Buildings: Same as proposed.
Table 9: Standard Design 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 |
N/A |
|
|
R-10 continuous insulation |
1.8 |
0.02 |
1.8 |
0.29 |
7.50 |
N/A |
|
|
Total assembly |
N/A |
N/A |
N/A |
N/A |
8.37 |
0.119 |
|
R-10 c.i. |
115 lb./ft3 CMU, solid grout |
8 |
0.45 |
115 |
0.20 |
0.87 |
N/A |
|
|
R-10 continuous insulation |
2.4 |
0.02 |
1.8 |
0.29 |
10.00 |
N/A |
|
|
Total assembly |
N/A |
N/A |
N/A |
N/A |
10.87 |
0.092 |
|
R-12.5 c.i. |
115 lb./ft3 CMU, solid grout |
8 |
0.45 |
115 |
0.20 |
0.87 |
N/A |
|
|
R-10 continuous insulation |
3.0 |
0.02 |
1.8 |
0.29 |
12.50 |
N/A |
|
|
Total assembly |
N/A |
N/A |
N/A |
N/A |
13.37 |
0.075 |
Source: California Energy Commission
These building descriptors apply to slab-on-grade or below-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.
Standard Design: Not applicable.
Standard Design: Existing Buildings: Not applicable.
Slab Floor Type
Applicability: All slab floors, required.
Definition: One of two types and two subtypes of floors in contact with ground:
1) Heated slab-on-grade floors,
2) Unheated slab-on-grade floors
3) Heated below-grade floors
4) Unheated below-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: restricted to the four selections listed above.
Input Restrictions: None.
Standard Design: The slab for type is unheated (either unheated slab-on-grade for slab-on-grade floors or unheated below-grade for below-grade floors).
Standard Design: Existing Buildings: Same as proposed.
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: surface.
This may include area, perimeter exposed.
Input Restrictions: None.
Standard Design: The geometry of the slab floor in the standard design building is identical to the slab floor in the proposed design.
Standard Design: Existing Buildings: Same as proposed.
Slab Floor Construction
Applicability: All slab floors, required.
Definition: A specification containing a series of layers that result in a construction assembly for the proposed design.
The first layer in the series represents the outside (or exterior) layer and the last layer represents the inside (or interior) layer. See the building descriptors above for slab floor construction type.
A description of how the slab is insulated (or not)
How the construction is described will depend on the energy simulation model. The construction can be represented by an F-factor that represents the entire construction (floor and insulation).
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: F-factor from Reference Appendix JA4; this is one selection from list 1 and one selection from list 2. Note that some combinations from list 1 and list 2 are not allowed, see Reference Appendix JA4 Table 4.4.8 and Table 4.4.7 for details.
List 1:
•None / 12 in vertical
•12 in horizontal / 24 in vertical
•24 in horizontal / 36 in vertical
•36 in horizontal / 48 in vertical
•48 in horizontal / Fully insulated slab
List 2:
•R-0 / R-20 / R-45
•R-5 / R-25 / R-50
•R-7.5 / R-30 / R-55
•R-10 / R-35
•R-15 / R-40
The compliance software shall also provide the following slab insulation options:
Ø Horizontal+Vertical, R-5 vertical down to the horizontal insulation and R-5 horizontal insulation extending 4 feet inwards from the perimeter
Ø Horizontal+Vertical, R-10 vertical down to the horizontal insulation and R-7 horizontal insulation extending 4 feet inwards from the perimeter
These two combinations of slab insulation are mapped to an F-factor in Appendix 5.4B.
Input Restrictions: The construction assembly, defined by an F-factor, must be equal to or more efficient than the mandatory F-factor requirements of §120.7 of the standards for newly constructed buildings, and §141.0 of the Energy Code for alterations.
For newly constructed buildings, F-factors shall be taken from Table 4.4.8 of Reference Appendix JA4 for heated slab floors and Table 4.4.7 for unheated slab floors. For all methods, inputs shall be consistent with the construction documents. For heated slab floors, the F-factor shall be determined by the mandatory R-value and installation requirements in §110.8 of the Energy Code. That information is used in Table 4.4.8 of Reference Appendix JA4 to determine the required F-factor. The same requirements apply for alterations.
Standard Design: Slab loss shall be modeled with the simple method (F-factor).
The standard design construction shall include the following layer:
Layer 1: Concrete 140lb/ft3 – 6 in. (R - 0.44)
The standard design shall include no insulation, equivalent to an F-factor of 0.73.
For alterations, the F-factor in the standard design shall be modeled as the more efficient of either the existing conditions, or the values stated above for newly constructed buildings standard design.
Standard Design: Existing Buildings: Same as proposed.
Partition Name
Applicability: All partitions, optional.
Definition: A unique name or code that relates the partition to the construction documents.
Units: Text: unique.
Input Restrictions: The text should provide a key to the construction documents.
Standard Design: Not applicable.
Standard Design: Existing Buildings: Not applicable.
Partition Geometry
Applicability: All partitions.
Definition: A geometric construct that defines the position and size of partitions that separate one thermal zone from another.
The construct shall identify the thermal zones on each side of the partition. Since solar gains are not generally significant for interior partitions, the geometry of partitions is sometimes specified as an area along with identification of the thermal zones on each side.
Units: Data structure: surface with additional information identifying the two thermal zones that the partition separates.
Input Restrictions: No restrictions other than agreement with the construction documents.
Standard Design: The geometry of partitions in the standard design building shall be identical to the proposed design.
Standard Design: Existing Buildings: Same as proposed.
Partition Construction
Applicability: All partitions.
Definition: A description of the construction assembly for the partition.
Units: Data structure: construction assembly.
Input Restrictions: As designed.
Standard Design: Partitions in the standard design shall be steel framed walls with 5/8-inch gypsum board on each side. For walls, partitions in the standard design building shall be steel-framed walls with 5/8-inch gypsum board on each side. For interior floors and ceilings, standard design construction shall be a metal deck, 4 inches of heavyweight (140 lb./ft3) concrete, and 3/4” thick carpet.
Standard Design: Existing Buildings: Same as proposed.
Demising Partition Construction
Applicability: All demising walls and demising partitions (ceilings, floors) that separate conditioned spaces from unconditioned spaces.
Definition: A description of the construction assembly for the partition.
Units: Data structure: construction assembly.
Input Restrictions: As designed.
Standard Design: For walls, when the proposed design demising partition is metal-framed or other, the standard design shall be a metal-framed wall meeting the mandatory U-factor requirements of §120.7 (b) of the Energy Code.
For walls, when the proposed design demising partition is wood-framed, the standard design shall be a wood-framed wall with the opaque portions of the wall meeting the mandatory U-factor requirements of §120.7 (b) of the Energy Code.
For windows in demising walls, the fenestration area shall equal the fenestration area of the proposed design. The window U-factor for fenestration in demising walls shall equal the fixed window prescriptive U-factor requirement of 5.5.7. Neither solar heat gain nor daylighting through interior demising windows will be modeled.
Demising ceiling partitions, separating conditioned space from unconditioned space and attics, shall be insulated to the same levels as exterior roofs in Chapter 5.5.3 Roofs. Demising floor partitions shall be insulated to the same levels as exterior floors in Chapter 5.5.5 Exterior Floors.
Standard Design: Existing Buildings: Demising ceiling partitions, separating conditioned space from unconditioned space and attics shall be insulated to the same levels as exterior roofs in Chapter 5.5.3 Roofs. Demising floor partitions shall be insulated to the same levels as exterior floors in 5.5.5 Exterior Floors.
The compliance software may have an option to model a building with simplified two-dimensional (2D) geometry. This is an optional capability as an alternative to modeling the three-dimensional (3D) geometry of a building. If the compliance software only provides a 2D building model, the following features cannot be modeled:
•Daylighting controls and dimming
•Exterior shading or self-shading
All mandatory and prescriptive daylight controls must be present when submitting a compliance project using compliance software that only models a building with 2D geometry.
The compliance software must pass all reference method tests corresponding to 2D geometry to meet certification requirements as compliance software. Consult Appendix 3B of the ACM Reference Manual for additional information. The compliance software must pass the rule set implementation tests, and for the sensitivity tests that verify simulation accuracy, there are 2D tests specified for building envelope, but for other building components such as lighting and HVAC, the compliance software is compared against the results of the reference method, which uses a 3D geometry model.
The compliance software must have sufficient information to specify each exterior surface when modeling a building with 2D geometry. At a minimum, building surface azimuth, elevation, and area are required and the tilt, azimuth and area is specified for roof components. The model must use only vertical walls for the analysis. The model follows all other ACM requirements for space and zone definitions, lighting, and HVAC specifications, and follows the same rules for the standard design and proposed design constraints.
The model also requires the following explicit inputs from the user:
•Total Building Story Count – the total number of stories
•Total Above Grade Stories – the total number of stories above grade, used in determination of multifamily classification