Over the past 15 years, green design and construction has become a fast-growing initiative as owners in the water and wastewater sector have adopted sustainable design policies to lower energy usage and to save cost. The push for these policies has been bolstered by unprecedented governmental programs and funding, public acceptance and the development of sustainable materials and equipment.
The primary driver for adopting sustainable design concepts is to lower long-term cost associated with facility operation and maintenance. According to the U.S. Department of Energy (DOE) in 2008, building impacts to the environment consist of approximately 39 percent of the total primary energy consumption in the United States. Buildings also consume more than 60 percent of the total electricity used in the United States, according to the Energy Information Association, and contribute to more than 39 percent of the total carbon dioxide emissions in the United States (Pew Center on Global Climate Change). ?
This impact is linked directly with our natural environment, economy, health and productivity. As a result, through education and public-policy advocates, owners are responding by requiring facilities to either be designed with green building principles or meet certification requirements by rating systems that encourage more energy-efficient systems.
Measurement and Rating for Green Design
One of the first rating systems was developed by the United States Green Building Council (USGBC), a not-for-profit organization established in 1993. The rating system, Leadership in Energy and Environmental Design (LEED), set the standard for more efficient building operation and maintenance. Today LEED not only focuses on building operation and maintenance, but also includes building types, land use, sustainable and environmentally beneficial materials and products, innovation and construction strategies aimed at reuse, recycle and waste management.
More recently the Institute for Sustainable Infrastructure (ISI), a not-for-profit organization, along with the Zofnass Program for Sustainable Infrastructure at Harvard University has developed a measurement and rating system called ?Envision.? Envision is aimed specifically at the sustainability of civil infrastructure projects measuring and rating the projects community, environmental and economic benefits.
LEED Certification Challenges for Water and Wastewater
The LEED rating system was developed as an assessment tool for evaluating the performance of design and construction from a standpoint of sustainability. Even with all its modification and improvements, LEED focuses primarily on inhabited commercial, industrial warehouse and residential building projects. This poses a challenge to owners, water and wastewater design professionals and constructors required to LEED-certify facilities on water and wastewater projects.
Generally, water and wastewater facility buildings are process-related, and the greatest challenge to certification is meeting the prerequisite for minimum energy performance in these spaces. Although the water and wastewater equipment manufacturing industry has responded to the need for more energy-efficient and sustainable equipment, water and wastewater processes consume considerable amounts of electricity. To get this credit, an energy efficiency model must be performed and a variance for equipment not meeting the minimum energy efficiencies must be obtained. To obtain a variance, a request has to be made to USGBC with documentation showing that the equipment requiring the variance is ?Industry Standard.? Other challenges may include:
- Limited site availability for protected habitats or open space;
- Lack of alternative transportation facilities;
- Vehicular loading requirements that prohibit or limit alternative impervious surfaces;
- Conflicting stormwater design requirements with permitting agencies; and
- Conflicting client-developed design and material standards.
To overcome these challenges requires that the owner, design professionals and constructors develop a culture of open, participatory communications with advanced planning and team integration to identify areas of conflict and develop solutions to obtain certification. This can be best done through a delivery method that encourages early participation by all parties, such as design-build.
Choosing a Delivery Method
Inherent challenges to obtaining certification for sustainable design include the delivery method. A study completed by the Charles Pankow Foundation in 2009 indicated that team integration influences the success of delivering a high-performance sustainable project and obtaining LEED certification. Similarly, studies point out that the traditional design-bid-build (DBB), and to some extent, construction manager at-risk delivery methods limit the contractor?s participation and ability to contribute to sustainable objectives based on procurement procedures, materials, equipment and payment provisions (Lapinski, et al. 2006, Riley et al., 2003).
Using the traditional delivery method of DBB requires two separate procurement phases ? acquisition of the design team and acquisition of the contractor. Projects seeking LEED certification using DBB tend to have a lower success rate of achieving LEED certification because the guarantee to deliver a certified project does not reside with the engineer, but rather with the contractor. Since the contract is selected based on low-bid and paid by a fixed lump-sum price, a guarantee to deliver a certified project influences the bid price and increases the likelihood of claims if the engineers bid package did not include all of the requirements for construction strategies or has errors or omissions.
Design-build is a project delivery method in which the owner retains both design and construction services in the same contract from a single legal entity referred to as the Design-Builder. The Design-Builder is selected either by a competitive proposal process or a qualifications-based process, and payment is either through a fixed lump-sum price or a cost plus fee not to exceed Guaranteed Maximum Price (GMP). This delivery method allows the builder to be involved early in the process providing constructability reviews, cost estimates, schedule adjustments and value-added design input. Under this delivery method, the Design-Builder warrants the design and is responsible for the cost of any errors or omissions eliminating claims.
Final Thoughts
The design-build delivery method creates a way for the owner to put the liability of design, construction, commissioning and certification contractually onto a signal source. A single source of responsibility that promotes collaboration between the owner, designer and contractor facilitates the certainty of LEED certification. ?
Cheryl Robitzsch, P.E., is the director of design for the water division of The Haskell Co.
