Michigan Administrative Code › Department - Licensing and Regulatory Affairs › Bureau of Construction Codes › Construction Code Commission General Rules › Construction Code › Part 10 - MICHIGAN UNIFORM ENERGY CODE › Section R. 408.31069 - Air leakage

Current through Vol. 24-12, July 15, 2024
Rule 1069. Sections R402.4, R402.4.1, R402.4.1.1,
						R402.4.1.2, R402.4.2, R402.4.3, R402.4.4, and Table R402.4.1.1 of the code are
						amended to read as follows:
R402.4 Air leakage. The building thermal envelope shall
						be constructed to limit air leakage in accordance with the requirements of
						Sections R402.4.1 through R402.4.4.
R402.4.1. Building thermal envelope. The building thermal
						envelope shall comply with Sections R402.4.1.1 and R402.4.1.2.
R402.4.1.1. Installation (mandatory). The components of
						the building thermal envelope as listed in Table R402.4.1.1 shall be installed
						in accordance with the manufacturers instructions and the criteria listed in
						Table R402.4.1.1, as applicable to the method of construction. The sealing
						methods between dissimilar materials shall allow for differential expansion and
						contraction.
R402.4.1.2. Testing (prescriptive). The building or
						dwelling unit shall be tested and verified as having an air leakage rate of not
						exceeding 4 air changes per hour. Testing shall be conducted with a blower door
						at a pressure of 0.2 inches (5.08 mm) w.g. (50 pascals).
Where required by the code official, testing shall be
						conducted by a certified independent third party. Certification programs shall
						be approved by the state construction code commission. A written report of the
						results of the test shall be signed by the party conducting the test and
						provided to the code official. Testing shall be performed at any time after
						creation of all penetrations of the building thermal envelope.
All of the following apply during testing:
1. Exterior windows, doors, and fireplace and stove doors
						shall be closed, but not sealed, beyond the intended weatherstripping or other
						infiltration control measures.
2. Dampers including exhaust, intake, makeup air,
						backdraft, and flue dampers shall be closed, but not sealed beyond intended
						infiltration control measures.
3. Interior doors, installed at the time of the test,
						shall be open.
4. Exterior doors for continuous ventilation systems and
						heat recovery ventilators shall be closed and sealed.
5. Heating and cooling systems, if installed at the time
						of the test, shall be turned off.
6. Supply and return registers, if installed at the time
						of the test, shall be fully open. R402.4.2. Fireplaces (mandatory). New
						wood-burning masonry fireplaces shall have tight-fitting flue dampers and
						outdoor combustion air.
R402.4.3. Fenestration air leakage (mandatory). Windows,
						skylights, and sliding glass doors shall have an air infiltration rate of no
						more than 0.3 cfm per square foot (1.5 L/s/m2), and
						swinging doors no more than 0.5 cfm per square foot (2.6
						L/s/m2), when tested according to NFRC 400 or
						AAMA/WDMA/CSA 101/I.S.2/A440 by an accredited, independent laboratory and
						listed and labeled by the manufacturer.
Exception: Site-built windows, skylights, and
						doors.
R402.4.4. Recessed lighting (mandatory). Recessed
						luminaires installed in the building thermal envelope shall be sealed to limit
						air leakage between conditioned and unconditioned spaces. All recessed
						luminaires shall be IC-rated and labeled as having an air leakage rate not more
						than 2.0 cfm (0.944 L/s) when tested in accordance with ASTM E 283 at a 1.57
						psf (75 Pa) pressure differential. All recessed luminaires shall be sealed with
						a gasket or caulk between the housing and the interior wall or ceiling
						covering.
TABLE R402.4.1.1
AIR BARRIER AND INSULATION INSTALLATION
COMPONENT
CRITERIAa
Air barrier and thermal barrier
A continuous air barrier shall be installed in
									 the building envelope.
Exterior thermal envelope contains a continuous
									 air barrier.
Breaks or joints in the air barrier shall be
									 sealed.
Air-permeable insulation shall not be used as a
									 sealing material.
Ceiling/attic
The air barrier in any dropped ceiling/soffit
									 shall be aligned with the insulation and any gaps in the air barrier sealed.
									 Access openings, drop down stair, or knee wall doors to unconditioned attic
									 spaces shall be sealed.
Walls
Corners and headers shall be insulated and the
									 junction of the foundation and sill plate shall be sealed.
The junction of the top plate and top of
									 exterior walls shall be sealed.
Exterior thermal envelope insulation for framed
									 walls shall be installed in substantial contact and continuous alignment with
									 the air barrier.
Knee walls shall be sealed.
Windows, skylights and doors
The space between window/door jambs and framing
									 and skylights and framing shall be sealed.
Rim joists
Rim joists shall be insulated and include the
									 air barrier.
Floors
(including above-garage, and cantilevered
									 floors)
Insulation shall be installed to maintain
									 permanent contact with underside of subfloor decking.
The air barrier shall be installed at any
									 exposed edge of insulation.
Crawl space walls
Where provided in lieu of floor insulation,
									 insulation shall be permanently attached to the crawlspace walls.
Exposed earth in unvented crawl spaces shall be
									 covered with a Class I vapor retarder with overlapping joints taped.
Shafts, penetrations
Duct shafts, utility penetrations, and flue
									 shafts opening to exterior or unconditioned space shall be sealed.
Narrow cavities
Batts in narrow cavities shall be cut to fit,
									 or narrow cavities shall be filled by insulation
that on installation readily conforms to the
									 available cavity space.
Garage separation
Air sealing shall be provided between the
									 garage and conditioned spaces.
Recessed lighting
Recessed light fixtures installed in the
									 building thermal envelope shall be air tight, IC rated, and sealed to the
									 drywall.
Plumbing and wiring
Batt insulation shall be cut neatly to fit
									 around wiring and plumbing in exterior walls, or insulation that on
									 installation readily conforms to available space shall extend behind piping and
									 wiring.
Shower/tub on exterior wall
Exterior walls adjacent to showers and tubs
									 shall be insulated and the air barrier installed separating them from the
									 showers and tubs.
Electrical/phone box on exterior walls
The air barrier shall be installed behind
									 electrical or communication boxes or air-sealed boxes shall be
									 installed.
HVAC register boots
HVAC register boots that penetrate building
									 thermal envelope shall be sealed to the subfloor or drywall.
Fireplace
An air barrier shall be installed on fireplace
									 walls.
a. In addition, inspection of log walls shall be in
						accordance with the provisions of ICC-400.