Decoding the green construction codes

Engineers should understand the difference between IgCC and ASHRAE 189.1 energy compliance code provisions.


Voluntary green building rating systems such as the U.S. Green Building Council’s LEED program have had significant impacts on the building industry. Some jurisdictions have attempted to make LEED certification a requirement for new buildings but have encountered a need for a code compliance path to document performance. The USGBC assisted in the development of both the ICC International Green Construction Code (IgCC) and ASHRAE 189.1, Standard for the Design of High-Performance, Green Buildings Except Low-Rise Residential Buildings, to fill this void.

Both codes focus on the five categories of sustainability addressed in LEED New Construction: Site Sustainability, Water Use Efficiency, Energy Efficiency, Indoor Environmental Quality, and Materials and Resources. Furthermore, both codes include an additional section regarding Operation and Maintenance.

The IgCC and Standard 189.1 are not guides or ratings systems. They are written in mandatory code language and intended for adoption and enforcement by the local and state level. In earlier versions of IgCC, ASHRAE 189.1 was a “jurisdictional compliance option,” meaning the local authority must choose between 189.1 and IgCC. With IgCC 2012, a building may now choose to comply with its standard requirements or those of 189.1.

Several major differences within the energy efficiency sections differentiate the two codes. With all energy units converted to Btus, IgCC is based on source energy use, while ASHRAE 189.1 is based on site energy cost. Just as energy cost and energy consumption are two completely different metrics, so are site and source energy. Different energy-saving measures will apply to a project, depending whether site energy cost or source energy use is the applicable metric. A model executed according to the calculations of one code cannot easily be compared to the other. A section of the IgCC also requires that the person performing the energy simulation be a professional engineer or architect in the state where the project is being constructed; ASHRAE 189.1 currently does not have a similar requirement.

Both codes contain comparable requirement categories in other sections, but with notable differences. The following table summarizes the key differences between ASHRAE 189.1 and IgCC 2012:

The IgCC has more detailed requirements for building energy metering and demand response, while ASHRAE 189.1 provides more detailed sections on fan power and demand controlled ventilation. If a project requires compliance with IgCC, there is always the option of using either IgCC or ASHRAE 189.1. For projects pursuing LEED certification, the energy model will compare energy cost. Overall, using ASHRAE 189.1 as a compliance path can minimize modeling time and increase cost-based savings.


Bridgette Baugher is an energy engineer with Southland Industries. Her career focus is on improving energy efficiency in new and existing buildings through the use of analysis and auditing tools. She served on the Center for the Built Environment’s Livable Buildings Jury in 2009 and 2010.   

No comments
The Top Plant program honors outstanding manufacturing facilities in North America. View the 2013 Top Plant.
The Product of the Year program recognizes products newly released in the manufacturing industries.
The Engineering Leaders Under 40 program identifies and gives recognition to young engineers who...
A cool solution: Collaboration, chemistry leads to foundry coat product development; See the 2015 Product of the Year Finalists
Raising the standard: What's new with NFPA 70E; A global view of manufacturing; Maintenance data; Fit bearings properly
Sister act: Building on their father's legacy, a new generation moves Bales Metal Surface Solutions forward; Meet the 2015 Engineering Leaders Under 40
Cyber security cost-efficient for industrial control systems; Extracting full value from operational data; Managing cyber security risks
Drilling for Big Data: Managing the flow of information; Big data drilldown series: Challenge and opportunity; OT to IT: Creating a circle of improvement; Industry loses best workers, again
Pipeline vulnerabilities? Securing hydrocarbon transit; Predictive analytics hit the mainstream; Dirty pipelines decrease flow, production—pig your line; Ensuring pipeline physical and cyber security
Upgrading secondary control systems; Keeping enclosures conditioned; Diagnostics increase equipment uptime; Mechatronics simplifies machine design
Designing positive-energy buildings; Ensuring power quality; Complying with NFPA 110; Minimizing arc flash hazards
Building high availability into industrial computers; Of key metrics and myth busting; The truth about five common VFD myths

Annual Salary Survey

After almost a decade of uncertainty, the confidence of plant floor managers is soaring. Even with a number of challenges and while implementing new technologies, there is a renewed sense of optimism among plant managers about their business and their future.

The respondents to the 2014 Plant Engineering Salary Survey come from throughout the U.S. and serve a variety of industries, but they are uniform in their optimism about manufacturing. This year’s survey found 79% consider manufacturing a secure career. That’s up from 75% in 2013 and significantly higher than the 63% figure when Plant Engineering first started asking that question a decade ago.

Read more: 2014 Salary Survey: Confidence rises amid the challenges

Maintenance and reliability tips and best practices from the maintenance and reliability coaches at Allied Reliability Group.
The One Voice for Manufacturing blog reports on federal public policy issues impacting the manufacturing sector. One Voice is a joint effort by the National Tooling and Machining...
The Society for Maintenance and Reliability Professionals an organization devoted...
Join this ongoing discussion of machine guarding topics, including solutions assessments, regulatory compliance, gap analysis...
IMS Research, recently acquired by IHS Inc., is a leading independent supplier of market research and consultancy to the global electronics industry.
Maintenance is not optional in manufacturing. It’s a profit center, driving productivity and uptime while reducing overall repair costs.
The Lachance on CMMS blog is about current maintenance topics. Blogger Paul Lachance is president and chief technology officer for Smartware Group.