DC Code Check: Residential Life Safety Systems

Single-family homes, townhouses, and duplexes in Washington, DC are subject to the following codes:

• 2012 ICC Residential Code (IRC)
• 2017 DC Construction Code
• 2017 DC Existing Building Code (if we're talking about a renovation and/or addition)

The three types of life safety systems most likely to be required  are sprinklers, smoke detectors/alarms, and carbon monoxide detectors/alarms (which are often combined with smoke alarms). 
See the 3 flowcharts below to determine whether your project requires each of these. 
If sprinklers are required, their design must follow NFPA 13D or ICC P2904, which are fed from a domestic water system and are much simpler than NFPA 13 or NFPA 13R systems for commercial and low/midrise multifamily buildings, respectively.
FAQ: Alterations under the existing building code are categorized as Level 1 (remove and replace), Level 2 (reconfigure up to 50%) or level 3 (reconfigure over 50%).