Internationally, code officials and designers recognize the need for a modern, up-to-date code governing the impact of buildings and structures on the environment. This code is designed to meet this need through model code regulations that contain clear and specific requirements with provisions that promote safe and sustainable construction in an integrated fashion with the ICC Family of Codes. This 2018 International Green Construction Code® (IgCC®) is the first fully integrated edition of the IgCC to be developed cooperatively by ICC and ASHRAE.

    This comprehensive green code establishes minimum regulations for building systems and site considerations using prescriptive and performance-related provisions. It is intended to be 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 Mechanical Code®, International Code Council Performance Code®, International Plumbing Code®, International Private Sewage Disposal Code®, International Property Maintenance Code®, International Residential Code®, International Swimming Pool and Spa Code®, International Wildland-Urban Interface Code® and International Zoning Code®.

    This code has been developed in collaboration with the following Cooperating Sponsors: The American Institute of Architects (AIA); ASHRAE; the U.S. Green Building Council (USGBC); and the Illuminating Engineering Society (IES). ICC wishes to thank these Cooperating Sponsors for recognizing the need for the development of a comprehensive set of green regulations that are enforceable, usable and adoptable.

    The I-Codes, including this International Green Construction Code, are used in a variety of ways in both the public and private sectors. Most industry professionals are familiar with the I-Codes as the basis of laws and regulations in communities across the U.S. and in other countries. However, the impact of the codes extends well beyond the regulatory arena, as they are used in a variety of nonregulatory settings, including:

    • Voluntary compliance programs such as those promoting sustainability, energy efficiency and disaster resistance.

    • The insurance industry, to estimate and manage risk, and as a tool in underwriting and rate decisions.

    • Certification and credentialing of individuals involved in the fields of building design, construction and safety.

    • Certification of building and construction-related products.

    • U.S. federal agencies, to guide construction in an array of government-owned properties.

    • Facilities management.

    • “Best practices” benchmarks for designers and builders, including those who are engaged in projects in jurisdictions that do not have a formal regulatory system or a governmental enforcement mechanism.

    • College, university and professional school textbooks and curricula.

    • Reference works related to building design and construction.

    In addition to the codes themselves, the code development process brings together building professionals on a regular basis. It provides an international forum for discussion and deliberation about building design, construction methods, safety, performance requirements, technological advances and innovative products.

    This code is founded on principles intended to establish provisions consistent with the scope of a green construction code that adequately protects the 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. This is achieved by comprehensive provisions that are enforceable, useable and adoptable.


    The 2018 International Green Construction Code is the third edition of the IgCC. In 2015, ICC and ASHRAE partnered in the development of this new version of the IgCC sponsored by AIA, ASHRAE, ICC, IES and USGBC. The previous two editions (2012 and 2015) were developed utilizing ICC’s Code Development Process as part of the ICC Family of Codes.

    As part of the partnership with ASHRAE, the responsibility for code provisions is now split between the ICC and ASHRAE processes. ICC is responsible for Chapter 1, Scope and Administration. ICC coordinated the technical provisions developed by ASHRAE with the provisions in Chapter 1 of the 2015 IgCC. The remainder of the code is the technical content that is based on the provisions of the 2017 edition of ANSI/ASHRAE/ICC/USGBC Standard 189.1, Standard for the Design of High-Performance Green Buildings Except Low-Rise Residential Buildings (Standard 189.1) developed using the American National Standards Institute (ANSI)-approved ASHRAE consensus process. The Standing Standards Project Committee 189.1 (SSPC) serves as the consensus body that developed the standard.

    USER NOTE: The code is formatted utilizing ICC’s code format for chapter and section number designations. However, in order to provide the requisite road map to the technical provisions of Standard 189.1, the Standard 189.1 section number is included in parentheses following the IgCC section number – e.g., “Section 101.2 (1.) Purpose.” The IgCC section number is 101.2 and the corresponding section number/title in Standard 189.1 is “Section 1 Purpose.” In some cases where the text of the IgCC is based on Standard 189.1, the text has been edited to be consistent with ICC’s publication style guidelines.

    Scope and Administration (ICC – Chapter 1)

    As noted previously, the provisions in Chapter 1 are primarily based on Chapter 1 of the 2015 IgCC. The text of Section 101 has been coordinated and correlated with Standard 189.1 Sections 1, 2 and 4 entitled “Purpose,” “Scope” and “Administration and Enforcement,” respectively. Sections 102109 are basically identical to those contained in the 2015 edition of the IgCC as there are no corresponding Standard 189 sections.

    Technical Content (ASHRAE – Chapters 2 – end, including appendices)

    The technical content of the code contains the provisions from Standard 189.1, which was originally published in 2009 through a collaborative effort involving ASHRAE, IES, and USGBC. In 2015, ICC was added as an additional cosponsor of the standard, which reflected a Memorandum of Understanding signed in 2014 by ASHRAE, AIA, ICC, IES, and USGBC to better align green building goals through Standard 189.1, the IgCC, and the LEED certification system. As part of that agreement, the 2017 edition of Standard 189.1 serves as the technical content of this code. Prior to this agreement, the 2012 and the 2015 versions of the IgCC included Standard 189.1 as a project compliance option.

    Building projects, which are defined in Standard 189.1 (and now in the IgCC), including both the building and the site, result in significant energy and environmental impacts through their design, construction, and operation. The U.S. Green Building Council reports that buildings in the United States produce 40% of U.S. carbon dioxide emissions, are responsible for 41% of U.S. energy consumption, account for 14% of U.S. potable water consumption, and use 40% of raw materials in their construction and operation. In addition, building development frequently converts land from biologically diverse natural habitat that helps manage rainwater to impervious hardscape with reduced biodiversity. While buildings consume energy and have other environmental impacts, they exist primarily to serve occupants who live, work, and otherwise use buildings. Buildings also contribute significantly to national economies. Based on a combination of research and practical experience, it is clear that buildings can provide these services with reduced energy use, greenhouse gas emissions, water use, construction waste, heat island and light pollution effects, and impacts on the atmosphere and other resources. Furthermore, a 2015 Economic Impact Study by the USGBC finds that the U.S. green building industry supports over 2 million jobs annually and results in a median state average economic contribution of $934 million.

    The far-reaching influence of buildings, and the benefits provided by high-performance green buildings, have led many organizations to pursue efforts to reduce their energy and environmental impacts. Based on ASHRAE’s and the other cosponsors’ ongoing responsibilities to support such actions, Standing Standard Project Committee (SSPC) 189.1 has contributed to building sustainability goals by updating Standard 189.1 in response to input from the building community, the public at large, and project committee members. Compliance with this code will further reduce energy and environmental impacts through high-performance building design, construction, and operation, while providing indoor environments that support the activities, health, and comfort of building occupants and contribute positively to local economics by providing high-quality jobs and conserving natural resources.

    The project committee considers a variety of factors in developing the provisions of Standard 189.1, including published research, justification for proposals received from outside the committee, and ultimately the committee members’ professional judgment. Cost-benefit assessment, while an important consideration, is not a necessary criterion for inclusion of any given requirement in Standard 189.1. However, the practicality and existing application of any new requirements are considered before they are included.

    Standard 189.1, and now the IgCC, address site sustainability, water use efficiency, energy use efficiency, indoor environmental quality, materials and resources, and construction and plans for operation. The 2017 edition of Standard 189.1 reflects the approval of 75 separate addenda to the 2014 edition. Some highlights among these changes include the following:

    • General. Clarified the purpose and scope; revised the purpose to add resilience and a statement of intent that the document be broadly adoptable.

    • Site. Updated requirements for pedestrian walkways, allowable sites, prohibited development, neighborhood assets, public transit access, and electric vehicle charging infrastructure; added new requirements for vegetated roofs, bicycle paths, and construction waste management.

    • Water. Made all of the water efficiency requirements mandatory, eliminating the performance option in Chapter 6; updated requirements for irrigation of plants; added new requirements for water-bottle filling stations, reverse osmosis, and water softeners when they are part of the building design, and for preplumbing of dual plumbing systems when reclaimed or other alternate water sources are expected to become available in the future.

    • Energy. Updated requirements to reflect changes in ANSI/ASHRAE/IES Standard 90.1-2016, including reference to Climate Zone 0; updated lighting tables with improved efficiencies; updated equipment efficiency tables; revised envelope requirements (with associated revisions to an informative appendix); conversion of Energy Performance Option A to use the Performance Cost Index; and updated CO2 emission factors for different energy sources; added new requirements for automated demand response and deleted Energy Performance Option B; added a new informative appendix with an energy compliance path that builds on the International Energy Conservation Code (IECC) instead of Standard 90.1.

    • IEQ. Updated requirements for control of soil gas entry, material emissions, acoustical control, and daylighting; added new requirements for control of moisture associated with envelope infiltration and HVAC systems, venting of combustion products to the outdoors, IEQ surveys of building occupants, and glare control.

    • Materials and resources. Revised the section title and scope; updated requirements for lifecycle assessment.

    • Construction and plans for operation. Updated requirements for commissioning and envelope airtightness testing; added a new informative appendix with additional information on the commissioning process.

    For Standard 189.1 and now this edition of the IgCC, all chapters other than Chapters 5, 6, and 10 use the following format:

    xxx.1 General. This subsection includes a statement of scope and addresses other broad issues for the section.

    xxx.2 Compliance Paths. This subsection indicates the compliance options available within a given section.

    xxx.3 Mandatory Provisions. This subsection contains mandatory provisions that apply to all projects (i.e., provisions that must be met and may not be ignored in favor of provisions found in other subsections).

    xxx.4 Prescriptive Option. This subsection, an alternative to the Performance Option, contains prescribed provisions that must be met in addition to all mandatory provisions. Prescribed provisions offer a simple compliance approach that involves minimal calculations.

    xxx.5 Performance Option. This subsection, an alternative to the Prescriptive Option, contains performance-based provisions that must be met in addition to all mandatory provisions. Performance provisions offer a more complex alternate compliance approach that typically involves simulation or other calculations.


    The maintenance responsibilities for updating the IgCC are shared between ICC and ASHRAE, as follows:

    Scope and Administration (Chapter 1: ICC process)

    Chapter 1 of the International Green Construction Code will be kept up to date through the review of proposed changes submitted by code enforcement 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 ICC Code Development Process reflects principles of openness, transparency, balance, due process and consensus, the principles embodied in OMB Circular A-119, which governs the federal government’s use of private-sector standards. The ICC process is open to anyone; there is no cost to participate, and people can participate without travel cost through the ICC’s cloud-based app, cdpAccess©. A broad cross section of interests are represented in the ICC Code Development Process. The codes, which are updated regularly, include safeguards that allow for emergency action when required for health and safety reasons.

    The code development committees evaluate and make recommendations regarding proposed changes to the codes. Their recommendations are then subject to public comment and council-wide votes. The ICC’s governmental members—public safety officials who have no financial or business interest in the outcome—cast the final votes on proposed changes.

    The contents of this work are subject to change through the code development cycles and by any governmental entity 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. The next opportunity to propose changes to Chapter 1 of the IgCC will be ICC’s 2019 Group A Code Development Process. For more information, go to ICC’s website at iccsafe.org.

    Technical Content (Chapters 2 - end, including appendices: ASHRAE process)

    The technical content of this code is based on Standard 189.1. SSPC 189.1 considers and administers changes to Standard 189.1 as a continuous maintenance standard and provides interpretations as requested. Proposed changes to the standard may originate within or outside of the committee. The committee welcomes proposals for improving the standard using the ANSI-approved ASHRAE continuous maintenance procedure. A continuous maintenance proposal (CMP) form can be found online at https://www.ashrae.org/technical-resources/standards-and-guidelines/standards-and-guidelines-under-continuous-maintenance, and may be completed and submitted at any time. The committee takes formal action on every proposal received, which may lead to changes to the published standard. ASHRAE posts approved addenda in publication notices on the ASHRAE website. To receive notice of all public reviews, approved and published addenda, errata, and interpretations as well as meeting notices, ASHRAE encourages interested parties to sign up for the free ASHRAE Internet Listserv for Standard 189.1. (https://www.ashrae.org/technical-resources/standards-and-guidelines/project-committee-list-servers).

    Coordination of the International Codes

    The coordination of code provisions is one of the strengths of the ICC family of model codes. The codes can be used as a complete set of complementary documents, which will provide users with full integration and coordination of provisions. Individual codes can also be used in subsets or as stand-alone documents.

    Italicized Terms

    Words and terms that are defined in Chapter 3, Definitions, Abbreviations, and Acronyms are italicized where they appear in code text. Where such words and terms are not italicized, common-use definitions apply. The words and terms selected have code-specific definitions that the user should read carefully to facilitate better understanding of the code.


    All title in and copyright in this code belong to ICC and ASHRAE jointly. Maintaining copyright allows the ICC and ASHRAE to fund their respective missions through sales of books, in both print and electronic formats. The ICC welcomes adoption of its codes by jurisdictions that recognize and acknowledge the ICC’s copyright in the code, and further acknowledge the substantial shared value of the public/private partnership for code development between jurisdictions and the ICC.

    The ICC also recognizes the need for jurisdictions to make laws available to the public. All I-Codes and I-Standards, along with the laws of many jurisdictions, are available for free in a nondownloadable format on the ICC’s website. Jurisdictions should contact the ICC at adoptions@iccsafe.org to learn how to adopt and distribute laws based on the International Green Construction Code in a manner that provides necessary access, while maintaining the ICC’s copyright.

    While the I-Code development procedure is thorough and comprehensive, the ICC, its members and those participating in the development of the codes disclaim any liability resulting from the publication or use of the I-Codes, or from compliance or noncompliance with their provisions. The ICC does not have the power or authority to police or enforce compliance with the contents of this code.

    To facilitate adoption, sections of this code contain blanks for fill-in information that needs to be supplied by the adopting jurisdiction as part of the adoption legislation. For this code, please see:

    Section 101.1. Insert: [NAME OF JURISDICTION]