Notice of Intended Action

State mechanical code—adoption of International Mechanical Code, 2021 Edition, by reference, 61.1 to 61.5

Untitled document

ARC 5476C


Notice of Intended Action

Proposing rule making related to state mechanical code

and providing an opportunity for public comment

The Plumbing and Mechanical Systems Board hereby proposes to amend Chapter 61, "State Mechanical Code," Iowa Administrative Code.

Legal Authority for Rule Making

This rule making is proposed under the authority provided in Iowa Code section 105.4.

State or Federal Law Implemented

This rule making implements, in whole or in part, Iowa Code section 105.4.

Purpose and Summary

The proposed amendments include the adoption by reference of the International Mechanical Code (IMC), 2021 Edition. The Board previously adopted the 2018 Edition of the IMC. The Board is required by law to adopt the most recent version of the IMC.

Notable changes in the most recent version include provisions to maintain indoor air quality and correlate to the International Energy Conservation Code (IECC), allow type II commercial kitchen exhaust to be used in energy recovery ventilation systems and require wood-burning residential heaters to be EPA-certified, thus limiting high-particulate emissions. Additional changes reinforced safety-based requirements and correlation with the International Building Code (IBC), which include minimum wall thickness for subducts penetrations of shaft enclosures, emergency egress requirements for machinery rooms and the comprehensive rewrite of the refrigeration piping sections including safety-related provisions.

Fiscal Impact

This rule making has no fiscal impact to the State of Iowa.

Jobs Impact

After analysis and review of this rule making, no impact on jobs has been found.


Any person who believes that the application of the discretionary provisions of this rule making would result in hardship or injustice to that person may petition the Board for a waiver of the discretionary provisions, if any, pursuant to the Board's general waiver provisions contained in 641—Chapter 31.

Public Comment

Any interested person may submit written comments concerning this proposed rule making. Written comments in response to this rule making must be received by the Board no later than 4:30 p.m. on March 16, 2021. Comments should be directed to:

Kane Young

Plumbing and Mechanical Systems Board

Lucas State Office Building

321 East 12th Street

Des Moines, Iowa 50319


Public Hearing

No public hearing is scheduled at this time. As provided in Iowa Code section 17A.4(1)"b," an oral presentation regarding this rule making may be demanded by 25 interested persons, a governmental subdivision, the Administrative Rules Review Committee, an agency, or an association having 25 or more members.

Review by Administrative Rules Review Committee

The Administrative Rules Review Committee, a bipartisan legislative committee which oversees rule making by executive branch agencies, may, on its own motion or on written request by any individual or group, review this rule making at its regular monthly meeting or at a special meeting. The Committee's meetings are open to the public, and interested persons may be heard as provided in Iowa Code section 17A.8(6).

The following rule-making actions are proposed:

Item 1. Amend rule 641—61.1(105), definition of "Life Safety Code," as follows:

"Life Safety Code" means the 2000 2021 edition of the Life Safety Code of the National Fire Protection Association, Batterymarch Park, Quincy, MA 02269, or the most recent version of the Life Safety Code adopted by reference by the federal Centers for Medicare and Medicaid Services.

Item 2. Amend rule 641—61.2(105), introductory paragraph, as follows:

641—61.2(105) Adoption by reference. The provisions Sections 101 and 102 and Chapters 2 to 15 of the International Mechanical Code, 2018 2021 edition, published by the International Code Council, 4051 West Flossmoor Road, Country Club Hills, IL 60478, are hereby adopted by reference as the requirements for the design, installation, maintenance, alteration, and inspection of mechanical systems that are permanently installed and utilized to provide control of environmental conditions and related processes within buildings , with the following amendments: and premises in Iowa.

Item 3. Rescind subrules 61.2(1) to 61.2(15).

Item 4. Renumber rules 641—61.3(105) and 641—61.4(105) as 641—61.4(105) and 641—61.5(105).

Item 5. Adopt the following new rule 641—61.3(105):

641—61.3(105) Amendments to International Mechanical Code. The International Mechanical Code (IMC), as adopted by reference in rule 641—61.2(105), shall be amended as follows:

61.3(1) Amend Section 101.2 by deleting the following: "Exception: Detached one- and two-family dwellings and townhomes not more than three stories above grade plane in height with a separate means of egress and their accessory structures not more than three stories above grade plane in height shall comply with this coded or the International Residential Code."

61.3(2) Amend Section 102 by adopting new Section 102.12 as follows:

102.12 Local authority

(a)Local jurisdictions may administer the permit, inspection, testing, and enforcement provisions contained in the state mechanical code adopted and amended by this chapter. Permit, inspection, testing, and enforcement provisions contained in this code shall not be administered by the Plumbing and Mechanical Systems Board or the state unless otherwise provided by law.

(b)Local jurisdictions may not adopt mechanical codes other than the state mechanical code adopted and amended by this chapter. Local jurisdictions may adopt additional amendments to the state mechanical code if the additional amendments are stricter than the state mechanical code as set forth in this chapter. Local jurisdictions that adopt additional amendments must provide copies of any local amendments to the board.

61.3(3) Amend Section 304.11 by deleting the last sentence and inserting in lieu thereof the following new exception:

Exception: Guards are not required where permanent fall arrest/restraint anchorage connector devices that comply with ANSI/ASSE Z 359.1 are affixed for use during the entire lifetime of the roof covering. The devices shall be evaluated for possible replacement when the entire roof covering is replaced. The devices shall be placed not more than 10 feet (3048 mm) on center along hip and ridge lines and placed not less than 10 feet (3048 mm) from roof edges and the open sides of walking surfaces.

61.3(4) Amend Section 306.1 by deleting the last sentence and inserting in lieu thereof: "An unobstructed level working space at least 30 inches deep and 30 inches wide shall be provided on any side of equipment where service access is required. The authority having jurisdiction may approve service reductions prior to equipment installation, provided that the manufacturer's instructions are met."

61.3(5) Delete Section 306.2 and insert in lieu thereof the following new section:

306.2 Appliances in rooms and closets. Rooms and closets containing appliances shall be provided with a door and an unobstructed passageway measuring not less than 36 inches wide and 80 inches high. A level service space not less than 30 inches deep and 30 inches wide shall be present at the front service side of the appliance with the door open.

61.3(6) Amend Section 306.5 by:

a. Adding the following to the end of the section: "If the tenants of a multiple tenant building have, or are allowed to have, mechanical facilities on the roof or which penetrate the roof, then roof access ladders must be provided for use by all such tenants and their agents and contractors in a manner that does not require accessing space under the control of another tenant."

b. Deleting the following: "Exception: This section shall not apply to Group R-3 occupancies."

c. Adopting new Section 306.5.3 as follows:

306.5.3 Visual screening of rooftop equipment. Equipment screening shall not be installed to the rooftop unit or the curb of the rooftop unit unless specified in the mechanical equipment manufacturer's installation instructions.

61.3(7) Delete Section 401.1 and insert in lieu thereof the following new section:

401.1 Scope. This chapter shall govern the ventilation of spaces within a building intended to be occupied. These buildings shall meet either the requirements of ASHRAE Standard 62.1, "Ventilation for Acceptable Indoor Air Quality," 2019 edition, published by the American Society of Heating, Refrigeration, and Air-Conditioning Engineers, 1791 Tullie Circle N.E., Atlanta, GA 30329, or the requirements contained in this chapter. Mechanical exhaust systems, including exhaust systems serving clothes dryers and cooking appliances; hazardous exhaust systems; dust, stock, and refuse conveyor systems; subslab soil exhaust systems; smoke control systems; energy recovery ventilation systems; and other systems specified in Section 502 shall comply with Chapter 5.

61.3(8) Add the following footnote "i" related to the gym, stadium, arena (play area) category of the sports and amusement occupancy classification in Table 403.3.1.1, Minimum Ventilation Rates:

i.When combustion equipment is intended to be used on the playing surface, additional dilution ventilation and/or source control shall be provided.

61.3(9) Add the following footnote "j" to Table 403.3.1.1 anywhere the term "smoking lounges" appears:

j.For ventilation purposes, "smoking" includes both combustible tobacco products and accessories and electronic smoking devices and accessories.

61.3(10) Delete Section 504.8.2 and insert in lieu thereof the following new section:

504.8.2 Duct installation. Exhaust ducts shall be supported at 4-foot (1219 mm) intervals and secured in place. The insert end of the duct shall extend into the adjoining duct or fitting in the direction of airflow. Ducts shall not be joined by screws or similar fasteners that protrude into the inside of the duct.

61.3(11) Delete Subsection 506.3.13.3 and insert in lieu thereof the following new subsection:

506.3.13.3 Termination location. Exhaust outlets shall be located not less than 10 feet (3048 mm) horizontally from parts of the same or contiguous buildings, adjacent buildings and adjacent property lines and shall be located not less than 10 feet (3048 mm) above the adjoining grade level. Exhaust outlets shall be located not less than 20 feet horizontally/vertically from or not less than 5 feet above air intake openings and operable doors and windows into any building.

61.3(12) The first sentence of Section 507.3 shall be amended to read: "Type II hoods shall be installed above dishwashers capable of heating water beyond 140 degrees Fahrenheit and appliances that produce heat or moisture and do not produce grease or smoke as a result of the cooking process, except where the heat and moisture loads from such appliances are incorporated into the HVAC system design or into the design of a separate removal system."

61.3(13) Delete Section 508.1.1 and insert in lieu thereof the following new section:

508.1.1 Makeup air temperature. All kitchen makeup air systems shall be verified by a certified TAB (testing and balance) contractor to heat makeup air to within 10 degrees of room temperature set point. The TAB contractor shall be certified by NEBB, TABB, or other certifying organization as approved by the Authority Having Jurisdiction.

61.3(14) Amend Section 601.5 by adopting new paragraph "9" as follows:

9.Return air openings shall be located at least 18 inches from supply air openings. Air throw shall be directed away from return air openings to reduce short cycling of air. Exception: Factory-made concentric duct terminations.

61.3(15) Amend Section 601.5 by adopting new paragraph "10" as follows:

10.One return air opening per floor is required on a central duct return system per ACCA Manual D, Appendix 8. Return air transfer openings are required on all bedrooms when dedicated return air openings are not used.

61.3(16) Amend Section 603 by adopting new Section 603.1.1 as follows:

603.1.1 Duct location. Air plenums and ducts located in floor and wall cavities shall be separated from unconditioned space by construction with insulation to meet energy code requirements. These areas include but are not limited to exterior walls, cantilevered floors, and floors above garages.

61.3(17) Delete Section 604.3 and insert in lieu thereof the following new section:

604.3 Coverings and linings. Duct coverings and linings, including adhesives where used, shall have a flame spread index of not more than 25 and a smoke-development index of not more than 50, when tested in accordance with ASTM E84 or UL 723, using the specimen preparation and mounting procedures of ASTM E2231. Duct coverings and linings shall not flame, glow, smolder or smoke when tested in accordance with ASTM C411 at the temperature to which they are exposed in service. The testing temperature shall not fall below 250ºF (121ºC). Coverings and linings shall be listed and labeled. The use of an air gap to meet R-value requirements for duct insulation shall be prohibited.

61.3(18) Amend Subsection 607.6.2.1 by adopting new Subsections 607. and 607. as follows:

607. Access ceiling radiation dampers shall be provided with an approved means of access that is large enough to permit inspection and maintenance of the damper and its operating parts. Dampers equipped with fusible links, internal operators for both shall be provided with either an access door that is not less than 12 inches (305mm) square, or a removable duct section.

607. Identification ceiling radiation damper locations and access points shall be permanently identified on the exterior by a label or marking acceptable to the authority having jurisdiction.

61.3(19) Delete all references to the "International Plumbing Code" and insert in lieu thereof "state plumbing code."

Public Health Department

Closed For Comments

This notice is now closed for comments. Collection of comments closed on 3/16/2021.

Official Document

  • State mechanical code—adoption of International Mechanical Code, 2021 Edition, by reference, 61.1 to 61.5
  • Published on 2/24/2021
  • 679 Views , 0 Comments
  • Notice of Intended Action

The official published PDF of this document is available from the Iowa General Assembly’s Administrative Rules page.

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View the Iowa Administrative Bulletin for 2/24/2021.

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Administrative Rule References

The following administrative rule references were added to this document. You may click a reference to view related notices.

Rule 641-61.1 Rule 641-61.2 Rule 641-61.2(1) Rule 641-61.2(15) Rule 641-61.3 Rule 641-61.4 Rule 641-61.5


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