Internationally, code officials recognize the need for a modern, up-to-date mechanical code addressing the design and installation of mechanical systems through requirements emphasizing performance. The International Mechanical Code®, in this 2012 edition, is designed to meet these needs through model code regulations that safeguard the public health and safety in all communities, large and small.

This comprehensive mechanical code establishes minimum regulations for mechanical systems using prescriptive and performance-related provisions. It is founded on broad-based principles that make possible the use of new materials and new mechanical designs. This 2012 edition is fully compatible with all of the International Codes (I-Codes®) published by the International Code Council (ICC), including the International Building Code®, International Energy Conservation Code®, International Existing Building Code®, International Fire Code®, International Fuel Gas Code®, International Green Construction CodeTM (to be available March 2012), International Plumbing Code®, ICC Performance Code®, International Private Sewage Disposal Code®, International Property Maintenance Code®, International Residential Code®, International Swimming Pool and Spa CodeTM (to be available March 2012), International Urban-Wildland Interface Code® and International Zoning Code®.

The International Mechanical Code provisions provide many benefits, among which is the model code development process that offers an international forum for mechanical professionals to discuss performance and prescriptive code requirements. This forum provides an excellent arena to debate proposed revisions. This model code also encourages international consistency in the application of provisions.


The first edition of the International Mechanical Code (1996) was the culmination of an effort initiated in 1994 by a development committee appointed by the ICC and consisting of representatives of the three statutory members of the International Code Council at that time, including: Building Officials and Code Administrators International, Inc. (BOCA), International Conference of Building Officials (ICBO) and Southern Building Code Congress International (SBCCI). The intent was to draft a comprehensive set of regulations for mechanical systems consistent with and inclusive of the scope of the existing model codes. Technical content of the latest model codes promulgated by BOCA, ICBO and SBCCI was utilized as the basis for the development. This 2012 edition presents the code as originally issued, with changes approved through the ICC Code Development Process through 2010. A new edition such as this is promulgated every 3 years.

This code is founded on principles intended to establish provisions consistent with the scope of a mechanical code that adequately protects public health, safety and welfare; provisions that do not unnecessarily increase construction costs; provisions that do not restrict the use of new materials, products or methods of construction; and provisions that do not give preferential treatment to particular types or classes of materials, products or methods of construction.


The International Mechanical Code is available for adoption and use by jurisdictions internationally. Its use within a governmental jurisdiction is intended to be accomplished through adoption by reference in accordance with proceedings establishing the jurisdiction’s laws. At the time of adoption, jurisdictions should insert the appropriate information in provisions requiring specific local information, such as the name of the adopting jurisdiction. These locations are shown in bracketed words in small capital letters in the code and in the sample ordinance. The sample adoption ordinance on page xi addresses several key elements of a code adoption ordinance, including the information required for insertion into the code text.


The International Mechanical Code is kept up to date through the review of proposed changes submitted by code enforcing officials, industry representatives, design professionals and other interested parties. Proposed changes are carefully considered through an open code development process in which all interested and affected parties may participate.

The contents of this work are subject to change both through the Code Development Cycles and the governmental body that enacts the code into law. For more information regarding the code development process, contact the Codes and Standards Development Department of the International Code Council.

While the development procedure of the International Mechanical Code assures the highest degree of care, ICC and ICC’s members and those participating in the development of this code do not accept any liability resulting from compliance or noncompliance with the provisions because ICC and its members do not have the power or authority to police or enforce compliance with the contents of this code. Only the governmental body that enacts the code into law has such authority.

Code Development Committee Responsibilities
(Letter Designations in Front of Section Numbers)

In each code development cycle, proposed changes to this code are considered at the Code Development Hearing by the International Mechanical Code Development Committee. Proposed changes to a code section whose number begins with a letter in brackets are considered by a different code development committee. For instance, proposed changes to code sections which have the letter [B] in front (for example, [B] 309.1), are considered by one of the International Building Code development committees (IBC-General) at the Code Development Hearing.

The content of sections in this code which begin with a letter designation is maintained by another code development committee in accordance with the following:

[A]=Administrative Code Development Committee;
[B]=International Building Code Development Committee (IBC—Fire Safety, General, Means
of Egress or Structural);
[EC]=International Energy Conservation Code Development Committee;
[F]=International Fire Code Development Committee; and
[FG]=International Fuel Gas Code Development Committee.

Note that, for the development of the 2015 edition of the I-Codes, there will be two groups of code development committees and they will meet in separate years. The groupings are as follows:

Group A Codes
(Heard in 2012, Code Change Proposals Deadline: January 3, 2012)
Group B Codes
(Heard in 2013, Code Change Proposals
Deadline: January 3, 2013)
International Building CodeAdministrative Provisions (Chapter 1 all codes except IRC and ICC PC, administrative updates to currently referenced standards, and designated definitions)
International Fuel Gas CodeInternational Energy Conservation Code
International Mechanical CodeInternational Existing Building Code
International Plumbing CodeInternational Fire Code
International Private Sewage
Disposal Code
International Green Construction Code
ICC Performance Code
International Property Maintenance Code
International Residential Code
International Swimming Pool and Spa Code
International Wildland-Urban Interface Code
International Zoning Code

Code change proposals submitted for code sections that have a letter designation in front of them will be heard by the respective committee responsible for such code sections. Because different committees will meet in different years, it is possible that some proposals for this code will be heard by a committee in a different year than the year in which the primary committee for this code meets.

For example, every section of Chapter 1 of this code is designated as the responsibility of the Administrative Code Development Committee, and that committee is part of the Group B code hearings. This committee will conduct its code development hearings in 2013 to consider all code change proposals for Chapter 1 of this code and proposals for Chapter 1 of all I-Codes. Therefore, any proposals received for Chapter 1 of this code will be deferred for consideration in 2013 by the Administrative Code Development Committee.

Another example is Section 606.4 of this code which is designated as the responsibility of the International Fire Code Development Committee. This committee will conduct its code development hearings in 2013 to consider code change proposals in its purview, which includes any proposals to Section 606.4.

In some cases, another committee in Group A will be responsible for a section of this code. For example, Section 607.3 has a [B] in front of the numbered section, indicating that this section of the code is the responsibility of one of the International Building Code Development Committees. The International Building Code is in Group A; therefore, any code change proposals to this section will be due before the Group A deadline of January 3, 2012, and these code change proposals will be assigned to the appropriate International Building Code Development Committee for consideration.

It is very important that anyone submitting code change proposals understand which code development committee is responsible for the section of the code that is the subject of the code change proposal. For further information on the code development committee responsibilities, please visit the ICC web site at

Marginal Markings

Solid vertical lines in the margins within the body of the code indicate a technical change from the requirements of the 2009 edition. Deletion indicators() are provided in the margin where an entire section, paragraph, exception or table has been deleted or an item in a list of items or in a table has been deleted.

Italicized Terms

Selected terms set forth in Chapter 2, Definitions, are italicized where they appear in code text. Such terms are not italicized where the definition set forth in Chapter 2 does not impart the intended meaning in the use of the term. The terms selected have definitions which the user should read carefully to facilitate better understanding of the code.