The new DC Green Building Code took effect as of April 2014, based on the 2012 International Codes (access ICC here: http://publicecodes.cyberregs.com/icod/index.htm) and intended to increase energy conservation in the nation's capital. There are 14 separate Word files of amendments (650+ pages) available for free at dcra.dc.gov, or if you want a single, very unofficial, bookmarked pdf of the amendments, let me know. Three amendments caught my eye on my first read:
1) The DC Green code (DCMR 12K) requires LEED rating for many buildings, but use a different criteria for multi-family.
302.2.4 Project containing residential occupancies.
Where a project contains 10,000 square feet (929 m2) or more of gross floor area for residential occupancies including the allocable area of common space, then the residential occupancies of the project shall be designed and constructed to meet or exceed the Enterprise Green Communities .....The residential component of the project shall not be required to meet a LEED standard.
All privately-owned projects that are (a) new construction or substantial improvement; and (b) 50,000 square feet (4645 m2) or more of gross floor area shall comply with Section 302.3. Privately-owned projects shall mean projects owned or developed by a non-governmental person which are not within the scope of Section 302.2 Criteria.
Enterprise Green Communities is a standard that is similar to LEED, with points are needed for certification, but has too many differences to list here. It may be hard for code officials to learn evolving, competing standards in the same code cycle.
2) DC amendment to the Mechanical Code requires that all dwelling units have forced ventilation AND operable windows equal to at least 4% of the floor area.
401.2 Ventilation required.
Every occupied space shall be ventilated by natural means in accordance with Section 402 or by mechanical means in accordance with Section 403. Each new dwelling unit shall be ventilated by mechanical means in accordance with Section 403 and shall have at least one opening to the outdoors for natural ventilation of not less than 4 percent of the floor area of the habitable spaces of the dwelling unitFor example, a classic 3 foot by 5 ft double hung window (50% opening max) is ok for 187 square feet room. Ventilation is nice, but it drives up energy costs, even if for a good cause of possibly improved health.
3) Section 1301.1.12.3 of the transition rule reads:
1301.1.12.3 Existing Design Contracts
Buildings and other structures under contract for design on or before August 2, 2013, for which no permit applications have been filed, shall be allowed to be filed, processed to issuance of permit, and any work authorized thereby shall be allowed to be carried to completion, under the definition of residential in the implementing regulations (Chapter 13A) in force on November 30, 2012, subject to the following conditions:
1. The applicant shall file the permit application, accompanied by plans and other information conforming to Sections 106.1 and 106.1.1, sufficiently complete to allow processing of the permit without substantial change or deviation, within one year after August 2, 2013;
So, if you had a contract to design a building and the contract is dated prior to August 2nd 2013, you can go in under the old code (but other time limits and caveats apply).