Mich. Admin. Code R. 408.30544b - [Effective 8/29/2025] Exterior walls

Rule 544b. Section R302.5.1 of the code is amended and table R302.1(1) is added to read as follows:

R302.5.1. Opening protection. Openings from a private garage directly into a room used for sleeping purposes shall not be permitted. Other openings between the garage and residence shall be equipped with solid wood doors not less than 1-3/8 inches, 35 millimeters, in thickness, solid or honeycomb-core steel doors not less than 1-3/8 inches, 35 millimeters, thick, or 20-minute fire-rated doors.

TABLE R302.1(1)

EXTERIOR WALL ELEMENT		MINIMUM FIRERESISTANCE RATING	MINIMUM FIRE SEPARATION DISTANCE
Walls	Fire-resistance rated	1 hour-tested in accordance with ASTM E 119 or UL 263 with exposure from both sides	< 5 feet
	Not fire-resistance rated	0 hours	>= 5 feet
Projections	Not alloweda	NA	< 2 feet
	Fire-resistance rated	1 hour on the underside	>= 2 feet to < 5 feet
	Not fire-resistance rated	0 hours	>= 5 feet
Opening in walls	Not allowed	N/A	< 3 feet
	25% maximum of wall area	0 hours	3 feet
	Unlimited	0 hours	5 feet
Penetrations	All	Comply with section R302.4	< 5 feet
		None required	5 feet

For SI: 1 foot = 304.8 millimeters.

N/A = Not applicable

a. except as allowed as per section R302.1 exceptions 3 and 4

Notes

Mich. Admin. Code R. 408.30544b

MR 19, Eff. 2/6/2016; 2025 MR 10, Eff. 8/29/2025