Challenges abound for plumbing engineers in the revised LEED guidelines (Version 3.0), which has changed the name of LEED for Existing Buildings to LEED-AP Operations + Maintenance.

Rendering of  the “153 Milwaukee St.” project in Milwaukee, WI. The renovation project included a complete replacement of the plumbing, HVAC and lighting systems. Rendering created by/courtesy of Eppstein Uhen Architects.

First established in 1998 by the United States Green Building Council (USGBC), the LEED (Leadership in Energy and Environmental Design) rating system has quickly become the industry benchmark for a building’s sustainability and energy performance. More and more owners, corporations and developers are choosing to register their buildings under one of the various LEED rating systems. This growing trend has created many issues that need to be resolved.

The first part of this article reviews these issues, first and foremost being the alignment of the various LEED rating systems. Other issues include the streamlined project review process, credentialing tiers, planned rating system upgrades and enhanced LEED online functionality. The second part of the article focuses on key changes to LEED-EB and other changes that the plumbing industry needs to be concerned about.

Rating System Alignment.LEED 2009, also known as LEED Version 3.0 (LEED v3), has aligned all LEED rating systems into a 110-point scale. (Note: LEED for Homes has not been aligned to a 110-point scale at this time.) The 110-point scale includes 100 base points and 10 bonus points. The revised rating systems include the newly implemented Regional Priority category, which allows for additional points when achieving credits identified as a regional priority.

Project Review. The Green Building Certification Institute (GBCI) is the non-profit entity that handles LEED project reviews for USGBC. GBCI has partnered with 10 ISO-certified bodies to provide consistent LEED project documentation review in a timely fashion. Additionally, LEED 2009 online provides detailed guidance to support the success of the LEED review process. Embedded calculators, project dates, project organization and individual assignment to projects are some of the enhanced features.

Credentialing. Credentialing tiers provide a better assessment of an individual’s qualifications when working on a LEED project. The three tiers are Green Associate, LEED Accredited Professionals (LEED-AP) and LEED-AP Fellow. Green Associate is achieved by passing an exam that demonstrates an individual’s knowledge of LEED core concepts and strategies. LEED-APs require the individual to have actual LEED project experience as well as pass a rating system specific exam. The requirements to become a LEED-AP Fellow is still under development; however, the goal of this credentialing tier is to demonstrate the individual has the ability to provide guidance to various designers and builders throughout the LEED process such that certification is achieved.

Exam Tracks. Another new feature of LEED 2009 is the implementation of additional exam tracks. Individuals can become LEED accredited under the Homes rating system as well as the Neighborhood Development rating system. LEED for New Construction is now known as LEED AP Building Design + Construction. LEED for Existing Buildings is now known as LEED AP Operations + Maintenance. LEED for Commercial Interiors is now known as LEED AP Interior Design + Construction.

LEED Upgrades. The LEED rating systems are tentatively planned to be upgraded on a biennial cycle. Similarly, LEED-APs and Green Associates are required to maintain their credentials via continuing educational programs on a biennial schedule. LEED-APs are required to acquire 30 units of continuing education every two years, and Green Associates are required to acquire 15 units of continuing education every year. Qualifying credentialing maintenance courses are provided by LEED faculty or the recently developed Educational Provider Program (EPP). USGBC national would like individuals to contact their local USGBC chapters to provide the required credential maintenance. Starting in 2011, LEED APs and Green Associates will be required to pay a $50 biennial maintenance fee to keep their credential active in addition to the required educational courses.

Illustration courtesy of

Key Changes for Existing Buildings

So how has LEED 2009 improved with respect to the existing building’s market? The biggest improvement is the route projects must follow to address energy consumption. Rather than blindly pursuing a commissioning process, project teams must access the building’s energy performance and discuss energy saving strategies with the owner. Energy audits can provide significant financial savings, both immediate and over the entire life-cycle of the facility.

At this time it is very advantageous to research available government money, as well as tax incentives, available for planned energy upgrades of the facility. Some projects may even be financed through government incentives and tax savings. Regardless of energy upgrades and equipment replacement projects, cost segregation studies can provide immediate savings for an owner.

When pursuing LEED in existing buildings, the first step is to verify the energy consumption is within the allowable limit.If the project does not meet the prerequisite for energy consumption it will not be LEED certified.Energy consumption can be reduced through equipment replacement, proper operation of mechanical systems, and lighting retrofits.

The next step is to assess the refrigerants currently being used by the building’s base refrigeration equipment. CFC-based refrigerants must be removed unless a replacement life-cycle cost analysis provides more than a 10-year payback. The life-cycle cost analysis must be performed by a third party. If the replacement life-cycle cost analysis provides less than a 10-year payback, the project team must remove the CFC-based refrigerant within five years after the project’s performance periods end.

Green Building Operations & Maintenance, formerly know as LEED for Existing Buildings – Operations & Maintenance, requires the alignment of performance periods. Performance periods are the time in which project data is tracked and recorded for LEED compliance. It is recommended that all performance periods are one year long and begin and end at the same time within the calendar year. Project submittal to the Green Building Certification Institute must occur within 60 days after the end of the performance periods.

Operations & Maintenance is the only LEED rating system that requires a project to recertify every five years to maintain LEED certification. Project teams will find the recertification process easier if all certification data is cataloged and ongoing maintenance is documented. The intent of recertification is to promote the ongoing sustainable operations of the facility. It is good practice to treat new construction projects in the same fashion.

WE Credit 2: Additional Indoor Plumbing Fixture and Fitting Efficiency

Plumbing Concerns

Plumbing engineers must access the water consumption of the building’s plumbing fixtures. The allowable limits of the Uniform Plumbing Code or International Plumbing Code can be exceeded by 20% or 60% depending on the age of the building or last plumbing retrofit. Project teams must consider the consequences of plumbing fixture replacements prior to implementation. Low-flow fixtures reduce the potable water consumed and provide lower water bills. However, they may cause expensive problems for a facility. Sewage conveyance systems require a minimum amount of water to move the sewage to the treatment plant. If a low flow water closet is installed, it may create what is known assuper sewage. Super sewage is sewage that becomes stuck on the way to the sewage plant due to lack of conveying water.

Plumbing engineers must also be aware of all applicable plumbing codes when evaluating graywater/stormwater systems. The LEED rating systems continually address the advantages of using graywater and stormwater for sewage conveyance and irrigation. However, local codes typically prohibit this.

Cooling tower water loops and process systems require make-up water. Utilizing non-potable water for make-up can provide a project with LEED credits while reducing the owner’s water bill. The designer must evaluate the amount of make-up water required and verify the non-potable source is capable of meeting the demand. Coordination with the chemical treatment company must also occur.

Plumbing engineers and designers should be aware of their ability to maximize their potential on a LEED project by specifying non-water supplied urinals, eighth-gallon flush urinals, dual-flush water closets, pressure-assist water closets and faucets with motion sensors. Strategic plumbing fixture selection can provide some of the easier, less expensive points on LEED projects.

Plumbing engineers must coordinate with the LEED Project Administrator when calculating the usage of the plumbing fixtures. Items that must be consistent in the calculation are the project’s full-time equivalent occupants, percentage of occupants that are male/female and if the building includes any usage groups.


As with all project members, plumbing engineers must assess the scope of the project to determine if the sustainable strategies they can offer are in the best interest of the owner. LEED point chasing may create additional problems in the future if not correctly assessed during the planning phase. The ultimate goal of the USGBC is market transformation. This will occur once we begin to implement sustainable features in all of our designs and practices.

Individual LEED accreditation and project LEED certification is a good start. However, market transformation requires a mindset shift. One that assesses project sites, buildings and mechanical systems based not only upon past experience and initial cost - but also how the project will effect future generations and our global environment.

Case Study: Remodeling an Existing Building

“153 Milwaukee St.” (Milwaukee, WI) is a project that involved the purchase and extensive renovation of an office building by the LaMacchia Group, a company member of USGBC. The renovation (see photo) included a complete replacement of the plumbing, HVAC and lighting systems, and a building envelope upgrade to enhance the building’s energy performance. The project, which has been submitted to the United States Green Building Council for LEED Gold certification, has reduced the energy consumption by 16.5% when compared to a code-compliant facility.

The LaMacchia Group occupies the second floor of the building and has promoted neighborhood revitalization from this remodeling project, which provides pedestrian access to numerous, local basic services. Building occupancies include offices, retail and a restaurant. The building has five tenants and a common area that connects the tenant spaces. The address of the common space is 153 Milwaukee (thus the project name). An address exists because the utility company requires an address to provide a meter, and there is a dedicated HVAC unit serving the common area.