Administrative Rules of Montana
Department 24 - LABOR AND INDUSTRY
Chapter 24.301 - BUILDING CODES
Subchapter 24.301.1 - Adoption and Incorporation by Reference of Uniform and Model Codes Having General Applicability
Rule 24.301.161 - INCORPORATION BY REFERENCE OF INTERNATIONAL ENERGY CONSERVATION CODE

(a) Subsections C103.1 and R103.1, General, are deleted and replaced with the following: "With each application for a building permit, and when required by the building official, plans and specifications shall be submitted. The building official may require plans and specifications be prepared by an engineer or architect licensed to practice by the state, except for owner-occupied, single-family dwelling houses."

(b) Subsections C105.2 and R105.2, Required Inspections, are deleted in their entirety when the code is used by the department. It remains undeleted and available for use for certified local governments using the code.

(c) "C402.5.1.2 Air barrier compliance is deleted and replaced with the following: "A continuous barrier for the opaque building envelope shall comply with the following: Buildings or portions of buildings, including group R and I occupancies, shall meet the provisions of Section C402.5.2 or C402.5.3 or R402.4.1.2 & R402.4.1.3."

(d) Subsection C405.2.4.2 Sidelit daylight zone is amended to remove requirement (3) in its entirety.

(e) Subsection C405.11 Automatic receptacle control function is deleted in its entirety.

(f) Subsection C405.12 Energy monitoring is deleted in its entirety.

(g) Table R402.1.3, INSULATION AND FENESTRATION REQUIREMENTS BY COMPONENT, is amending requirements for Climate Zone 6 as WOOD FRAMED WALL R-VALUE 'R-21 or R-20 + R-5ci or R-13 + R-10ci or R15ci.'

(h) Table 402.1.2, MAXIMUM ASSEMBLY U-FACTORS AND FENESTRATION REQUIREMENTS, is amending requirements as shown below in the table:

(i) Subsection R402.2.2, Ceilings Without Attics, is deleted and replaced with the following: "Where Table R402.1.3 would require insulation levels above R-30 and the design of the roof/ceiling assembly does not allow sufficient space for the required insulation, the minimum required insulation for such roof/ceiling assemblies shall be R-30. This reduction of insulation from the requirements of Table R402.1.3, shall be limited to 250 square feet or ten percent of the total insulated ceiling area, whichever is less. This reduction shall not apply to the U-factor alternative approach in Section R402.1.4, and the total UA alternative in Section R402.1.5."

(j) Subsection R402.2.10, Crawl Space Walls, is deleted and replaced with the following: "As an alternative to insulating floors over crawl spaces, crawl space walls shall be permitted to be insulated when the crawl space is not vented to the outside. Temporary crawl space vent openings are allowed during construction for crawl spaces that have insulated crawl space walls. These temporary crawl space vent openings shall be closed, sealed, and insulated to the same R-value of the surrounding crawl space wall insulation once construction is complete and prior to the time that the final building inspection would occur. Crawl space wall insulation shall be permanently fastened to the wall and shall extend downward from the floor, the entire height of the crawl space wall. Exposed earth in unvented crawl space foundations shall be covered with a continuous Class I vapor retarder. All joints of the vapor retarder shall overlap six inches and be sealed or taped. The edges of the vapor retarder shall extend at least six inches up the stem wall and shall be attached and sealed to the stem wall."

(k) Subsection R402.4.1.2, Testing, is deleted and replaced with the following: The building or dwelling unit shall be tested and verified as having an air leakage rate of not exceeding four air changes per hour in Climate Zone 6. Testing shall be conducted with a blower door at a pressure of 0.2 inches w.g. (50 Pascals). Where required by the code official, testing shall be conducted by an approved party. 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. During testing:

(l) Subsection R402.4.1.3, Leakage Rate, is amended as follows: "When complying with Subsection R401.2.1, the building or dwelling unit shall have an air leakage rate not exceeding 4.0 air changes per hour in Climate Zone 6, when tested in accordance with Subsection R402.4.1.2."

(m) Subsection R403.3.7, Exception: Building framing cavities may be used for return ducts if there is no atmospherically vented furnace, boiler, or water heater located in the house outside of a sealed and insulated room that is isolated from inside the thermal envelope and if the duct system has been tested as having a maximum total leakage not greater than 4 cfm/SF. The room walls, floor, and ceilings shall be insulated in accordance with the basement wall requirements of Table R402.1.3. A duct air leakage test shall not be required where the ducts and air handlers are located entirely within the building thermal envelope.

(n) Subsection R403.4, Mechanical System Piping Insulation, is deleted and replaced with "Mechanical system piping shall be insulated in accordance with subsections 610.11 and L 501.2 of the Uniform Plumbing Code (UPC) 2021 edition."

(o) Subsection R403.5, Service Hot Water Systems, is deleted and replaced with "Service hot water systems shall be insulated in accordance with subsection L 503.3.3 of the Uniform Plumbing Code (UPC) 2021 edition."

(p) Subsection R403.5.2, Hot Water Pipe Insulation, is deleted and replaced with "Hot water pipe insulation shall be insulated in accordance with subsections 610.11 and L 501.2 of the Uniform Plumbing Code (UPC) 2021 edition."

(q) Appendix CB, Solar-Ready Zone - Commercial. Appendix CB may be adopted by a certified city, county, or town building code jurisdiction. The department shall not apply or enforce Appendix CB.

(r) Appendix RB, Solar-Ready Provisions-Detached One- and Two-Family Dwellings and Townhouses. Appendix RB may be adopted by a certified city, county, or town building code jurisdiction. The department shall not apply or enforce Appendix RB.

(a) The department encourages owners, design professionals, and builders to voluntarily implement greater levels of energy efficiency in building design and construction than those required by the International Energy Conservation Code. Information regarding voluntary building standards for greater levels of energy efficiency can be obtained from the department by contacting the Department of Labor and Industry, Building Codes Program, P.O. Box 200517, Helena, MT 59620-0517, by telephone at 406-841-2056, or at the department's web site, http://bsd.dli.mt.gov/building-codes-permits.