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. 408.31066 - Systems

Current through Vol. 24-12, July 15, 2024
Rule 1066. Sections R403.2.1, R403.2.2, R403.4, and
						R403.4.2 of the code are amended to read as follows:
R403.2.1. Insulation (prescriptive). All portions of the
						air distribution system shall be installed in accordance with section M1601 and
						be insulated to an installed R-6 when system components are located within the
						building but outside the conditioned space, and R-8 when located outside to the
						building. When located within a building envelope assembly, at least R-8 shall
						be applied between the duct and that portion of the assembly farthest from
						conditioned space.
Exception: Portions of the air distribution system within
						appliances or equipment. R403.2.2. Sealing (mandatory). Ducts, air handlers,
						and filter boxes shall be sealed. Joints and seams shall comply with either the
						international mechanical code or international residential code, as
						applicable.
Exceptions:
1. Air-impermeable spray foam products may be applied
						without additional joint seals.
2. Where a duct connection is made that is partially
						inaccessible, 3 screws or rivets shall be equally spaced on the exposed portion
						of the joint so as to prevent a hinge effect.
3. Continuously welded and locking-type longitudinal
						joints and seams in ducts operating at static pressures less than 2 inches of
						water column (500 Pa) pressure classification shall not require additional
						closure systems.
Duct tightness shall be verified by either of the
						following:
1. Post construction test: Total leakage to the outside
						of a conditioned space or total leakage shall be less than or equal to 4 cfm
						(113.3 L/min) per 100 square feet (9.29 m2) of
						conditioned floor area when tested at a pressure differential of 0.1 inches w.
						g. (25 Pa) across the entire system, including the manufacturers air handler
						enclosure. All register boots shall be taped or otherwise sealed during the
						test.
2. Rough-in test: Total leakage shall be less than or
						equal to 4 cfm (113.3 L/min) per 100 square feet (9.29
						m2) of conditioned floor area when tested at a
						pressure differential of 0.1 inches w.g. (25 Pa) across the system, including
						the manufacturers air handler enclosure. All registers shall be taped or
						otherwise sealed during the test. If the air handler is not installed at the
						time of the test, total leakage shall be less than or equal to 3 cfm (85 L/min)
						per 100 square feet (9.29 m2) of conditioned floor
						area.
Exception: The total leakage test is not required for
						ducts and air handlers located entirely within the building thermal
						envelope.
R403.4.1. Circulating hot water systems (mandatory). All
						circulating service hot water piping shall be insulated to at least R-2.
						Circulating hot water systems shall include an automatic or readily accessible
						manual switch that can turn off the hot water circulating pump when the system
						is not in use.
Exceptions:
1. Factory-installed piping within HVAC equipment tested
						and rated in accordance with a test procedure referenced by this code.
2. Runout piping not exceeding 4 feet (1 219 mm) in
						length and 1 inch (25 mm) in diameter between the control valve and HVAC
						coil.
R403.4.2. Hot water pipe insulation (prescriptive).
						Insulation for hot water pipe with a minimum thermal resistance (R-value) of
						R-3 shall be applied to the following:
1. Piping larger than 3/4 inch (19.05 mm) nominal
						diameter.
2. Piping serving more than 1 dwelling unit.
3. Piping located outside the conditioned space.
4. Piping from the water heater to a distribution
						manifold.
5. Piping located under a floor slab.
6. Buried piping.
7. Supply and return piping in recirculation systems
						other than demand recirculation systems.