5.5. PRESCRIPTIVE BUILDING ENVELOPE OPTION

SECTION 5 BUILDING ENVELOPE 5.5 PRESCRIPTIVE BUILDING ENVELOPE OPTION Strike Section 5.5.1 of ASHRAE 90.1 in its entirety and insert a new Section 5.5.1 in its place in the Energy Conservation Code-Commercial Provisions to read as follows: 5.5.1 For a conditioned space, the exterior building envelope shall comply with either the nonresidential or residential requirements in Table 5.5. Strike Section 5.5.2 of ASHRAE 90.1 in its entirety and insert a new Section 5.5.2 in its place to read as follows: 5.5.2 If a building contains any semiheated space or unconditioned space, then the semi-exterior building envelope shall comply with the requirements for semiheated space in Table5.5. (See Figure 5.5.2.) Strike Tables 5.5-1 through 5.5-8 of ASHRAE 90.1 and insert a new Table 5.5 in their place in the Energy Conservation Code-Commercial Provisions to read as follows: TABLE 5.5 BUILDING ENVELOPE REQUIREMENTS FOR CLIMATE ZONE 4 (A,B,C)* Nonresidential Residential Semi-heated Opaque Elements Assembly Maximum Insulation Min. R-Value Assembly Maximum Insulation Min. R-Value Assembly Maximum Insulation Min. R-Value Roofs Insulation Entirely above Deck U-0.028 R-33 c.i. U-0.028 R-33 c.i. U-0.093 R-10 c.i. Metal Buildinga U-0.033 R-21+R-12 Ls or R-28 +R-9 Ls U-0.033 R-21+R-12 Ls or R-28+R-9 Ls U-0.082 R-19 Attic and Other U-0.0189 R-54 U-0.0189 R-54 U.0.034 R-30 Walls, above Grade Mass U-0.094 R-11 c.i. U-0.081 R-12.5 c.i. U-0.580 NR Metal Building U-0.054 R-0+R-17.5 c.i. U-0.045 R-0+R-21 c.i. U-0.0162 R-13 Steel Framed U-0.058 R-15+R-8 c.i. U-0.058 R-15+R-8 c.i. U-0.124 R-13 Wood Framed and Other U-0.058 R-15+R-4.1 c.i. U-0.058 R-15+R-4.1 c.i. U-0.089 R-13 Walls, below Grade Below Grade Wall C-0.119 R-8 c.i. C-0.092 R-11 c.i. C-1.140 NR Floors Mass U-0.051 R-16 c.i. U-0.046 R-18.4 c.i. U-0.107 R-6.3 c.i. Steel Joist U-0.035 R-33 U-0.034 R-33 U-0.052 R-19 Wood Framed and Other U-0.030 R-33 U-0.030 R-33 U-0.051 R-19 Slab-on Grade Floors Unheated F-0.520 R-20 for 24 in. F-0.520 R-20 for 24 in. F-0.730 NR Heated F-0.843 R-25 for 24 in. F-0.688 R-25 for 48 in. F-0.900 R-10 for 24 in. Opaque Doors Swinging U-0.45 U-0.45 U-0.700 Nonswinging U-0.45 U-0.45 U-1.450 a When using the R-value compliance method for metal building roofs, a thermal spacer block is required. Nonresidential Residential Semi-heated Fenestration Assembly Max. U Assembly Max. SHGC Assembly Min. VT/SHGC Assembly Max. U Assembly Max. SHGC Assembly Min. VT/SHGC Assembly Max. U Assembly Max. SHGC Assembly Min. VT/SHGC Vertical Glazing 0%-40% of Wall For all frame types For all frame types For all frame types Nonmetal framing (all) U-0.33 SHGC-0.36 1.10 U-0.33 SHGC-0.36 1.10 U-0.51 NR NR Metal framing (fixed) U-0.38 U-0.38 U-0.73 Metal framing, operable U-0.45 U-0.45 U-0.81 Metal framing (entrance door) U-0.69 U-0.61 U-0.77 Skylight, 0%-3% of Roof All types U-0.45 SHGC-all-0.36 NR U.0.45 SHGC-all-0.36 NR U-1.15 NR NR *The following definitions apply: c.i. = continuous insulation (see Section 3.2), FC = filled cavity (see Section A2.3.2.5), Ls = liner system (see Section A2.3.2.4), NR = no (insulation) requirement. Figure 5.5.2. Exterior and semiexterior building envelope. Strike Sections 5.5.3.1 through 5.5.3.6 of ASHRAE 90.1 in their entirety and insert new Sections 5.5.3.1 through 5.5.3.6 in their place in the Energy Conservation Code-Commercial Provisions to read as follows: 5.5.3.1 Roof Insulation. All roofs shall comply with the insulation values specified in Table 5.5. Sky-light curbs shall be insulated to the level of roofs with insulation entirely above deck or R-5.0, whichever is less. 5.5.3.1.1 Roof Solar Reflectance and Thermal Emittance. Roofs in Climate Zone 4 shall have one of the following: A minimum three-year-aged solar reflectance of 0.55 and a minimum three-year-aged thermal emittance of 0.75 when tested in accordance with CRRC-1 Standard. A minimum initial Solar Reflectance Index of 82 for roofs 2:12 or less and 39 for roofs greater than 2:12 in slope, when determined in accordance with the Solar Reflectance Index method in ASTM E1980 using a convection coefficient of 2.1 Btu/h·ft2·°F, based on three-year-aged solar reflectance and three-year-aged thermal emittance tested in accordance with CRRC-1 Standard. Exceptions: Ballasted roofs with a minimum stone ballast of 17 lb/ft2 or 23 lb/ft2 pavers. Vegetated roof systems that contain a minimum thickness of 2.5 in. of growing medium and covering a minimum of 75% of the roof area with durable plantings. Roofs where a minimum of 75% of the roof area is shaded during the peak sun angle on June 21 by permanent components or features of the building; or is permitted using a combination of 1 and 2 above. Decks constructed using wood or an approved bio-based decking material. The values for three-year-aged solar reflectance and three-year-aged thermal emittance shall be determined by a laboratory accredited by a nationally recognized accreditation organization and shall be labeled and certified by the manufacturer. 5.5.3.2 Above-Grade Wall Insulation. All above-grade walls shall comply with the insulation values specified in Table 5.5. Exception: Alternatively, for mass walls, where the requirement in Table 5.5 is for a maximum assembly U-0.151 followed by footnote “b,” ASTM C90 concrete block walls, ungrouted or partially grouted at 32 in. or less on center vertically and 48 in. or less on center horizontally, shall have ungrouted cores filled with material having a maxi- mum thermal conductivity of 0.44 Btu·in./h·ft2·°F. Other mass walls with integral insulation shall meet the criteria when their U-factors are equal to or less than those for the appropriate thickness and density in the “Partly Grouted, Cells Insulated” column of Table A3.1-3. When a wall consists of both above-grade and below-grade portions, the entire wall for that story shall be insulated on either the exterior or the interior or be integral. If insulated on the interior, the wall shall be insulated to the above-grade wall requirements. If insulated on the exterior or integral, the below- grade wall portion shall be insulated to the below-grade wall requirements, and the above- grade wall portion shall be insulated to the above-grade wall requirements. 5.5.3.3 Below-Grade Wall Insulation. Below-grade walls shall have a rated R-value of insulation no less than the insulation values specified in Table 5.5. Exception: Where framing, including metal and wood studs, is used, compliance shall be based on the maximum assembly C-factor. 5.5.3.4 Floor Insulation. All floors shall comply with the insulation values specified in Table 5.5. 5.5.3.5 Slab-on-Grade Floor Insulation. All slab-on-grade floors, including heated slab-on-grade floors and unheated slab-on-grade floors, shall comply with the insulation values specified in Table 5.5. 5.5.3.6 Opaque Doors. All opaque doors shall have a U- factor not greater than that specified in Table 5.5. Insert a new Section 5.5.3.7 in the Energy Conservation Code-Commercial Provisions to read as follows: 5.5.3.7 High-Speed Doors. High-speed doors that are intended to operate on average at least 75 cycles per day shall not exceed a maximum U-factor of 1.20 Btu/hr·ft2·°F (6.81 W/m2·K). Opening rate, closing rate, and average cycles per day shall be included in construction drawings. Sections 5.5.3.6 and 5.5.4.3 shall not apply for high-speed doors complying with all criteria in this section. Strike Table 5.5.3.1.1 of ASHRAE 90.1 in its entirety without substitution. 5.5.4.2 Fenestration Area Strike Sections 5.5.4.2.1 and 5.5.4.2.2 of ASHRAE 90.1 in their entirety and insert new Sections 5.5.4.2.1 and 5.5.4.2.2 in their place in the Energy Conservation Code-Commercial Provisions to read as follows: 5.5.4.2.1 Vertical Fenestration Area. The total vertical fenestration area shall not be greater than that specified in Table 5.5. Exception: Vertical fenestration complying with Exception (3) to Section 5.5.4.4.1. 5.5.4.2.2 Maximum Skylight Fenestration Area. The total skylight area shall not be greater than that specified in Table 5.5. Exception: The total skylight area is permitted to be increased to no greater than 6% of the gross roof area, provided the skylights meet all of the criteria in Exception (1) to Section 5.5.4.4.2 and the total daylight area under skylights is a minimum of half the floor area of the space. Strike Section 5.5.4.3 of ASHRAE 90.1 in its entirety and insert a new Section 5.5.4.3 in its place in the Energy Conservation Code-Commercial Provisions to read as follows: 5.5.4.3 Fenestration U-Factor. Fenestration shall have a U-factor not greater than that specified in Table 5.5. However, for locations in Climate Zone 1 with a cooling design temperature of 95°F and greater, the maximum allowed U-factors for vertical fenestration for all conditioned spaces, nonresidential and residential, are U-0.32 for non- metal framing, U-0.50 for fixed metal framing, U-0.65 for operable metal framing, and U-0.83 for entrance door metal framing. Exception: The U-factor for skylights is permitted to be increased to no greater than 0.90 Btu/h·ft2·°F in Climate Zones 1 through 3 and 0.75 Btu/h•ft2•°F in Climate Zones 4 through 8, provided the skylights meet all of the criteria in Exception (1) to Section 5.5.4.4.2. Strike Table 5.5.4.4.1 of ASHRAE 90.1 in its entirety and substitute a new Table 5.5.4.4.1 in its place in the Energy Conservation Code-Commercial Provisions to read as follows: TABLE 5.5.4.4.1 SHGC MULTIPLIERS FOR PERMANENT PROJECTIONS Projection Factor SHGC Multiplier (all other Orientations) SHGC Multiplier (North-Oriented 0-0.60 1.00 1.00 >0.60 - 0.70 0.92 0.96 >0.70 - 0.80 0.84 0.94 >0.80 - 0.90 0.77 0.93 >0.90 – 1.00 0.72 0.90 SOURCE: Final Rulemaking published at 67 DCR 6326 (May 29, 2020 – Part 2). The District of Columbia Energy Conservation Code (2017), referred to as the “Energy Conservation Code,” consists of ANSI/ASHRAE/IES 90.1-2013, Energy Standard for Buildings Except Low-Rise Residential Buildings (ASHRAE 90.1) and substantial portions of Chapter 7 of ANSI/ASHREA/IES 189.1-2014, Standard for the Design of High-Performance Green Buildings Except Low-Rise Residential Buildings (ASHRAE 189.1), published by the American Society of Heating, Refrigeration and Air-Conditioning Engineers (ASHRAE), and the Residential Provisions of the 2015 edition of the International Energy Conservation Code (International Energy Conservation Code), published by the International Code Council (ICC), as amended by the Energy Conservation Code Supplement of 2017 – Commercial Provisions (12-I[CE] DCMR) and the Energy Conservation Code Supplement of 2017 – Residential Provisions (12-I[RE] DCMR). The International Energy Conservation Code is copyrighted by the ICC and therefore is not republished here. However, a copy of the text may be obtained at: https://codes.iccsafe.org/public/document/IECC2015. ASHRAE 90.1 is copyrighted by ASHRAE and therefore is not republished here. However, the text of ASHRAE 90.1 may be reviewed at: https://www.ashrae.org/standards-research--technology. Portions of Chapter 7 of ASHRAE 189.1 are reprinted in the District of Columbia Energy Conservation Code Supplement by permission of ASHRAE and ICC. District of Columbia Municipal Regulations Energy Conservation Code Supplement of 2017 – Commercial Provisions 12-I[CE] DCMR § 5.5 District of Columbia Municipal Regulations Energy Conservation Code Supplement of 2017 – Commercial Provisions 12-I[CE] DCMR § 5.5