Statutes, codes, and regulations
District Of Columbia Administrative Code
Title 12 - CONSTRUCTION CODES SUPPLEMENT OF 2013Subtitle 12-I - ENERGY CONSERVATION CODE SUPPLEMENT OF 2013
Chapter 12-I4-CE - COMMERCIAL ENERGY EFFICIENCY
Rule 12-I4-CE02 - C402 - BUILDING ENVELOPE REQUIREMENTS

D.C. Mun. Regs. tit. 12, r. 12-I4-CE02

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Current through Register Vol. 72, No. 2, January 10, 2025
Rule 12-I4-CE02 - C402 - BUILDING ENVELOPE REQUIREMENTS

Strike Section C402.2.1.1 of the International Energy Conservation Code in its entirety and insert new Section C402.2.1.1 in the Energy Conservation Code in its place to read as follows:

C402.2.1.1

Roof solar reflectance and thermal emittance. Low-sloped roofs, with a slope less than 2 units vertical in 12 horizontal, directly above cooled conditioned spaces in Climate Zones 1, 2, 3 and 4 shall comply with one or more of the options in Table C402.2.1.1.

Exceptions: The following roofs and portions of roofs are exempt from the requirements in Table C402.2.1.1:

1. Portions of roofs that include or are covered by:
1.1. Photovoltaic systems or components.
1.2. Solar air or water heating systems or components.
1.3. Roof gardens or landscaped roofs.
1.4. Above-roof decks or walkways.
1.5. Skylights.
1.6. HVAC systems, components, and other opaque objects mounted above the roof.
2. Portions of roofs shaded during the peak sun angle on the summer solstice by permanent features of the building, or by permanent features of adjacent buildings.
3. Portions of roofs that are ballasted with a minimum stone ballast of 17 pounds per square foot (psf) (74 kg/m2) or 23 psf (117 kg/m2) pavers.
4. Roofs where a minimum of 75 percent of the roof area meets a minimum of one of the exceptions above.

TABLE C402.2.1.1

MINIMUM ROOF REFLECTANCE AND EMITTANCE OPTIONSa

Three-year-aged solar reflectanceb of 0.55 and three-year aged thermal emittancec of 0.75

Initial solar reflectanceb of 0.70 and initial thermal emittancec of 0.75

Three-year-aged solar reflectance indexd of 64

Initial solar reflectance indexd of 82

a. The use of area-weighted averages to meet these requirements shall be permitted. Materials lacking initial tested values for either solar reflectance or thermal emittance shall be assigned both an initial solar reflectance of 0.10 and an initial thermal emittance of 0.90.

Materials lacking three-year-aged tested values for either solar reflectance or thermal emittance shall be assigned both a three-year-aged solar reflectance of 0.10 and a three-year aged thermal emittance of 0.90.

b. Solar reflectance tested in accordance with ASTM C 1549, ASTM E 903 or ASTM E 1918.
c. Thermal emittance tested in accordance with ASTM C 1371 or ASTM E 408.
d. Solar reflectance index (SRI) shall be determined in accordance with ASTM E 1980 using a convection coefficient of 2.1 Btu/h x ft2x°F (12W/m2 x K). Calculation of aged SRI shall be based on aged tested values of solar reflectance and thermal emittance. Calculation of initial SRI shall be based on initial tested values of solar reflectance and thermal emittance.

Strike Section C402.2.6 of the International Energy Conservation Code in its entirety and insert new Section C402.2.6 in the Energy Conservation Code in its place to read as follows:

C402.2.6

Slabs on Grade. Where the slab-on-grade is in contact with the ground, the minimum thermal resistance (R-value) of the insulation around the perimeter of unheated or heated slab-on-grade floors, and the minimum thermal resistance of the insulation under heated slab-on-grade floors, shall be as specified in Table C402.2. The under-slab insulation shall be placed immediately below required vapor retarder. The perimeter insulation shall be placed on the outside of the foundation or on the inside of the foundation wall. The perimeter insulation shall extend downward from the top of the slab surface for a minimum distance as shown in the table or to the top of the footing, whichever is less, or downward to at least the bottom of the slab and then horizontally to the interior or exterior for the total distance shown in the table. Perimeter insulation extending away from the building foundation shall be protected by pavement or by a minimum of 10 inches (254 mm) of soil cover.

Exception: Where the unheated slab-on-grade floor is greater than 24 inches (610_mm) below the finished exterior grade, perimeter insulation is not required.

D.C. Mun. Regs. tit. 12, r. 12-I4-CE02

Final Rulemaking published at 61 DCR 3322 (March 28, 2014 Part 2)
The District of Columbia Energy Conservation Code (2013), referred to as the SEnergy Conservation Code, consists of the 2012 edition of the International Energy Conservation Code, published by the International Code Council, as amended by the District of Columbia Energy Conservation Code Supplement (2013)(12 DCMR I). 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: http://publicecodes.cyberregs.com/icod/iecc/2012/index.htm?bu=IC-P-2012-000014&bu2=IC-P-2012-000019.
Authority: Section 10 of the Construction Codes Approval and Amendments Act of 1986 (Act), effective March 21, 1987 (D.C. Law 6-216; D.C. Official Code § 6-1409 (2012 Repl.)) and Mayor"s Order 2009-22, dated February 25, 2009, as amended.