Every state has a section of its statutes or administrative code that is referred to as the building code. Each municipality has a own building code, usually found in the zoning ordinances, that adopts the state's building code and adds rules that apply only to the locality. Both often refer to national standards. Michigan's smoke detector regulations are a combination of national standards, local and state laws.
State regulations about smoke alarms and carbon monoxide detectors are in chapter 125.1504 of the Michigan Compiled Laws (MCL). Chapter 125 and other sections having to do with housing are collectively known as Act 230 of 1972 or the Stille Derossett-Hale Single Construction Code Act. The 1972 consolidation of building rules has been extensively amended since its adoption; the history of changes in each section is noted at the end of the current section. Chapter 125.1504c requires that owners of buildings constructed after 1974 install one smoke alarm in each dwelling unit. Manufactured homes and Bed and Breakfast establishments with fewer than 10 sleeping rooms are considered single-family units. Another section of the MCL, section 427.3 regulates hotels and other public lodging houses that do not have fire suppression systems; it requires that one smoke detector be placed in each sleeping room.
State law allows smoke detectors to be connected to building electrical systems but such "hardwired" units must have backup batteries. Single-station smoke alarms contain and alarm and power supply in one unit and multiple-station alarms are two or more alarms that are interconnected so that the activation of one causes all to sound. Batteries must function for at least five years according to a Shelby Township information sheet.
Cities, towns and counties adopt state laws and provide for enforcement of regulations relating smoke detectors. They may also refine or strengthen regulations within the areas that they govern. The city of Grand Rapids, for instance, defines a battery as "a lithium battery with a functional life expectancy of ten (10) years or more" and which is sealed in the smoke detector. Grand Rapids' code requires smoke alarms be placed in each sleeping unit and on each floor of single-family rental dwellings, multiple family dwellings and rental dwellings with three or more units. Dates of effectiveness and specifics may vary among municipalities but none may be more general than state regulations.
The National Fire Protection Association (NFPA) is an organization composed of engineers and other fire and life safety professionals that studies issues and makes recommendations followed nationally by governmental groups from federal, state and municipal governments to individual fire departments. Michigan's state code adopts NFPA 74 which specifies smoke alarm equipment and its use. NFPA standards change as technology does, keeping states like Michigan that adopt NFPA standards up to date. NFPA standards exist for everything from types of smoke detectors and power sources to their placement in buildings. Many local fire departments are NFPA members and can access specific information.