D.C. Mun. Regs. tit. 22, r. 22-B3240
No resident room or area shall have a general noise level from external sources in excess of forty-five (45) decibels.
In addition to meeting the requirement of subsection 3240.1 every effort shall be made in the facility to reduce noise levels, airborne sound transmission, and their impact.
Air space around each duct, other openings into rooms, and air space under and around each door and partition shall be properly sealed in order to maintain sound isolation.
In each duct and fan installation, noise generation shall not exceed by more than ten (10) decibels the permissible noise level attributable to the external source in the area served.
Wall-to-wall carpeting suitable for use under wheelchairs and rolling equipment shall be used in each resident area where the general noise level would otherwise exceed forty-five (45) decibels at anytime.
Window curtains of a soft fabric, fabric wall hangings, and other materials that absorb sound shall be used in each area of high noise generation.
D.C. Mun. Regs. tit. 22, r. 22-B3240