Lean and Green: The Role of Design-Build Mechanical Competencies in the
Design and Construction of Green Buildings
David Riley1, Victor Sanvido2, Michael Horman3,
Michael McLaughlin4, and Dan Kerr5
1
2
3
4
5
Associate Professor, Dept. of Arch. Eng. Penn State University, 104 Eng. Unit A,
University Park, PA, 16802; PH - 814.863.2079; email driley@engr.psu.edu
Senior Vice President, Southland Industries, vsanvido@engr.psu.edu
Assistant Professor, Dept. of Arch. Eng. Penn State University, 104 Eng. Unit A,
University Park, PA, 16802; PH - 814.863.2080; mjhorman@engr.psu.edu
Principal Engineer, Southland Industries, MMcLaughlin@southlandind.com
Design-Build Manager, McClure Company, dankerr@McClureco.com
Abstract
Building mechanical systems play a major role in both initial cost and life
cycle energy use in buildings. This research examines the role of design-build
mechanical contractors in meeting energy efficiency and first cost objectives on high
performance “green” building projects. Specifically, synergies between lean
principles which eliminate process and materials waste are evaluated for alignment
with green goals in resource minimization and energy efficiency. The role of designbuild mechanical contractors in achieving green buildings is explored through
engineering, design detailing, fabrication, and construction processes. Three
illustrative case studies are summarized to illustrate the unique abilities of designbuild mechanical contractors as valuable contributors on green projects. The results
of these case studies and interviews with design-build mechanical professionals are
summarized in descriptive tables in which waste reducing lean principles are applied
to achieve green results. Key results include the value of integrated design and
detailing of mechanical systems, the ability of design-build mechanical contractors to
take on more risk with innovative design solutions, and the benefits of early
involvement of expertise in estimating and constructability of mechanical systems on
building projects. Implications for the design process of green buildings and the role
of energy and mechanical engineering are discussed.
Introduction
High performance “green” buildings are being increasingly pursued by facility
owners and operators. Building mechanical systems play a major role in both initial
cost and life cycle energy use in buildings. In high performance “green” and
“sustainable” buildings, these systems are even more critical given the importance of
energy use and minimal material use to project success. Architecture and engineering
professionals play key roles in developing integrated design solutions for green
building projects, however many contractors are vital to completing the design
process. In the case of building mechanical systems, the design capability of a
mechanical contractor can be crucial to the development of energy efficient and
“right-sized” mechanical systems. To exploit the capabilities of design-build
mechanical construction, research is needed to define and understand the
relationships between design-build processes and the overall resource and energy
efficiency of facilities. This research examines the role of design-build mechanical
contractors (DBMCs) in meeting energy efficiency and first cost objectives on high
performance building projects. Specifically, synergies between applied lean principles
which eliminate process and materials waste are evaluated for alignment with green
goals in resource minimization and energy efficiency. The role of design-build
mechanical contractors in achieving green buildings is explored through engineering,
design detailing, fabrication, and construction processes. Three case studies are
summarized to illustrate the potent and unique abilities of design-build mechanical
contractors as valuable contributors on green projects. Implications for the design
process of green buildings and the role of energy and mechanical engineering are
discussed.
Background
Riley et.al (2003) identify factors effecting the role of contractors on green
building projects based on a survey of owners, design organizations, and construction
professionals experienced in green construction. This investigation defined factors
that elevate the need for construction organizations on green building projects
including the need for more open lines of communication due to more complex
interdependencies between building systems and project organizations, and the need
for inclusive and integrated project teams. The study also notes that, in the US, the
leading owners seeking green buildings are government agencies, state and local
governments. Many of these agencies are, at the same time, moving toward the use
of design-build delivery systems.
This study also defines four key areas that construction organizations can
contribute to the success of green building projects: (1) estimating, emphasized by
the need for early and accurate costing of systems alternatives, (2) materials selection
in particular proper handling, storage, installation, finishing, final cleaning, and
training of maintenance personnel on the long term care of materials, (3) construction
waste minimization and recycling and the management of these processes on site, and
(4) indoor air quality management including the protection of the HVAC system from
pollutants, building time into construction schedules for off-gassing, and sequencing
work to minimize the exposure of materials to potential contamination, in particular
wet materials, and those with high volatile organic compounds (VOC’s).
Limited research has been performed on the specific role of specialty
contractors in the design and construction of buildings. Uher (1991) and Hinzie and
Tracey (1994) discuss the dysfunctional relationships typically created between
specialty contractors and general contractors as the result of highly constraining
contract language. Pietroforte (1997) identifies the mismatch between the typical
working relationships and the subcontracting practices between project team
members. The role of specialty contractors in the building process is evolving with
advancements in buildings systems, manufacturing, and specialty systems.
Tommelein and Ballard (1997) note the progressive shift from artisan work on site to
prefabricated components and off-site tasks, including detailed design documentation
and the procurement and fabrication of components. Gil et.al. (2000a and 2000b)
articulate the potential role of specialty contractors in the design process, and identify
four areas of contribution that specialty contractors can play in early design
processes. These include the ability to develop creative solutions that designers may
not be aware of, knowledge of space needs associated with construction processes
that require consideration in the layout and design of systems, knowledge of
fabrication and construction capabilities, and knowledge of supplier lead times and
reliability that can effect material equipment and material selection. Techniques and
potential barriers to specialty contractor involvement in design are also presented.
The use of design-build contracts for specialty construction has not been the
focus of significant research. Many building systems, for example fire protection
systems, and curtain wall systems are delivered almost exclusively be deign-build
specialty contracts. The reasons for this are typically due to the inherent knowledge
of the construction process and specialty codes that need to be considered during the
design process. Riley and Lee (2001) describe the increasing trends in the use of
design-build mechanical contractors in the United States, and their increasing role on
building projects. Riley (1998) describes the role of the mechanical contractor in the
coordination process, and notes the significant portion of mechanical systems design
that are completed by specialty trades during the coordination process.
The impact of contractors early in the project has been studied as part of
broader empirical research into project delivery methods and contractor behavior. In
their seminal study comparing design-bid-build, construction management at risk, and
design-build, Konchar and Sanvido (1998) showed that design-build projects
performed 33% faster and 6% cheaper than either of design-bid-build or construction
management at risk. The ability to have construction input in design helps the
decision-making process in many design-build projects, particularly as the owner’s
“go/no-go” decision diminishes 45% of the level of influence on a project (Sanvido
and Konchar 1999; Gao 2001). In another study, Horman et al. (2003) examined the
impact of the design-build team selection methods on project performance, showing
that best value selection is correlated strongly to best project performance results.
Horman (2004) found the highest impact areas of early steel fabricator involvement to
be; close consultation with the structural engineer, close consultation with the general
contractor, and improved mill ordering.
Research Approach
This research definines key competencies and competitive advantages of
design-build mechanical contractors that make value-added contributions on high
performance “green” building projects. Case studies of design-build mechanical
projects were evaluated for instances in which design-build expertise combined with
early involvement permitted design solutions that saved initial cost and improved the
energy efficiency of facilities. Interviews were also performed with executive and
operational professionals working for DBMCs to assess the business processes that
capitalize on competitive advantages of the design-build mechanical process.
Instances in which the reduction of process and product waste through applied “lean”
principles, and resulting costs savings and energy efficiencies that can contribute to
“green” goals of high performance building projects were collected and organized
into summary tables.
Three Illustrative Case Studies
This research reflects the evaluation of over 20 design-build mechanical projects.
Three illustrative case studies were selected for presentation in this paper which
highlights exemplar practices in which DBMCs were able to produce highly efficient
mechanical systems designs combined with first-cost savings when compared to
solutions developed by design-bid-build processes.
Case Study 1: Central Plant Energy Retrofit - The Masonic Homes of
Elizabethtown, PA is a 1400 acre continuing care complex. Operating since 1910,
approximately 1200 staff personnel care for 1400 residents. The building occupancies
consist of retirement living, ranging from condominiums to a fully staffed hospital.
Services offered on campus include childcare facilities and administrative offices for
the Masonic organization.
Heating, domestic hot water, laundry steam, and hospital process steam loads
were formerly served by a coal fired steam plant. This plant burned approximately
5,000 tons of coal annually. Three boilers generated 120 psi steam to serve dryers and
rollers in the laundry. The steam pressure was reduced to 50 psi for general campus
distribution. Requiring year-round on-line steam, the Masonic organization grew
interested in a combined heat and power (CHP) retrofit strategy at their facilities.
After several failed feasibility studies seeking a retrofit solution, a local
design-build mechanical contractor presented Masonic Homes with an innovative
combined heat and power solution and was hired to develop the scope of work,
conduct applicable energy models, and determining an early Guaranteed Maximum
Price (GMP) for the recommendations. Eventually the DBMC acted as the prime
contractor and construction manager for the following scope of work: (1)
decommission the existing coal-fired high-pressure steam plant, (2) construct a new
dual fuel hot water plant centrally located to the connected loads, (3) implement 300
kW of natural gas-fired microturbine generators in a CHP strategy, and (4) construct
small satellite heating plants where steam is needed for process requirements.
The customer’s budgetary and schedule limitations demanded the adaptive re-use
of existing infrastructure as a necessary component of the design. The project team
discovered an under-utilized building on the campus ideal to house the new central
plant. Total cost savings as compared to the construction of a new facility exceeded
$200,000 and reduced the construction cycle-time. Additional cost and schedule
savings were realized through the adaptation of the existing primary and redundant
steam supply lines to hot water supply and return duty. Re-using these lines saved the
customer in excess of $500,000 in construction costs. In summary, the following
factors were identified were found to contribute directly to the success of this project:
 Implementation of New Technology: Few consulting engineers would have been
willing to accept the risk of designing the microturbine system for installation and
start-up by others.
 Adaptive re-use of infrastructure: The final solution for the project included the
re-use of existing pipe that had not previously been identified by feasibility
studies conducted by consulting engineers.
 Construction Phasing: The timing of the project necessitated a fast-track
construction process and the use of temporary boilers at the various satellite
mechanical rooms. Since the existing piping network was being re-used, there


was a time when the coal-fired plant had to be decommissioned prior to start-up
of the new central plant. It was vital that the design engineers, the construction
project manager, and the field crews could communicate openly and immediately.
Design-build Subcontractors: The DBMC subcontracted the electrical design and
construction to a trusted integrated design-build partner. By doing so, they
acquired a similar single source of responsibility for the extremely critical
electrical systems. In a reversal of normal roles, the DBMC also hired a general
contractor that was very experienced with the design-build delivery system.
In-house Commissioning: The mechanical systems were commissioned by
engineers and service technicians directly employed by the DBMC. These
employees had direct involvement in the design process, which simplified the
start-up and testing process at the end of the project.
After its commissioning in August of 2002, two full years of operating have
validated the system design and performance. The turbines exceeded their up-time
goal of 91%, and the project demonstrated a better rate of return than presented in the
feasibility study. The GMP was maintained but the energy and operational savings
were exceeded. Actual plant emissions are lower than those originally projected.
Case Study 2: Large-scale Federal Office Renovation: The Pentagon Renovation is
becoming one of the best examples of a high performance green building. The $1
billion, twelve year renovation will refurbish 6.6 million square feet of office and
service space. Employing innovative project delivery methods including design-build,
and award fee, incentive-based contracting, this project will provide the Department
of Defense a state-of-the-art green facility.
This project provides an example of how enabling design-build mechanical
processes and competencies can help to efficiently achieve high performance
objectives. The HVAC system for Phase II of the renovation was designed to
eliminate the use of return air duct and allow induction units to locally mix supply air.
This allowed for a higher ceiling height and improved penetration of daylight in most
of the interior spaces. The induction unit system also reduced the number of
mechanical rooms from 118 to nine. Installation was streamlined with a 20% cost
savings compared to Phase 1. Over its life, the system will also save 9% on energy
costs compared to the Phase 1 Design.
Similar to Case Study 1, Pentagon Renovation exemplifies how DBMC’s can
enable the implementation of innovative design solutions that consulting engineering
firms might view as risky due to the requirements of installation. This project also
illustrates a trend found in other cases studies in which HVAC distribution systems
were reduced in size and combined with equipment “right sized” to provide highvelocity and high/low temperature supply air or water. As a result, fans, chillers, and
other systems run in higher ranges of operating efficiency, resulting in lower energy
costs. In addition, piping and ductwork sizes are reduced, speeding construction
processes and reducing the labor risk component of a DBMC contact. In the case of
the Pentagon, the reduction in mechanical rooms and distribution sizes also translated
into dramatic improvements in the efficiency of the architectural design and improved
day lighting in the facility, thus contributing more broadly to the green goals of the
project.
Case Study 3 Integrated Design and Detailing in Healthcare Construction - This
project illustrates how the early involvement of a DBMC can help to develop costsaving solutions for the complex mechanical systems required in healthcare facilities.
This 256,000 square foot facility will become the first health care facility in
California in which a DBMC will be the engineer of record.
One significant source of waste in the design-bid-build process for mechanical
systems is the redundancies involved with the development of engineering design
drawings for bidding, and the subsequent development of shop and fabrication
drawings by mechanical contractors. A key feature of this case study was the
approach used by the DBMC to integrate design and detailing. In this process, scaled
engineering drawings are developed by experienced detailers that can incorporate
fabrication and constructability information during the early stages of design
documentation. As a result, the design is developed with constructability and
production in mind, minimizing construction cost while maximizing opportunities for
prefabrication. A by-product of this process is the frequent alignment of systems for
linear flow that minimizes costly and labor intensive fittings. As a result, distribution
systems are more efficient, and equipment sizes can be reduced. While this process
takes place, effort and time of design engineers normally spent developing
engineering drawings for bidding is redirected to the development of highly detailed
design schematics that identify all coordination issues and items frequently missed on
standard engineering designs, such as valve groupings, power requirements, and
interface points between control systems and mechanical systems. These drawings
are easier for code officials to review, and when combined with scaled engineering
drawings, result in more accurate cost estimates for electrical and control systems.
On the project evaluated, the first time this system was fully implemented by the
DBMC, the final mechanical system design was priced at a 13% first cost savings
than an original system developed for the owner by a consulting engineer. In
addition, the system efficiency exceeded the rigid requirements of California’s Title
24 Energy Incentive program, and resulted in a $40,000 rebate to the owner.
Another aspect of this project worth noting was the reduction in need for firesmoke dampers through the early involvement of the DBMC which allowed for the
design of the air distribution systems and zones to be considered with the layout of
architectural walls. Fire-smoke dampers are required to maintain separation between
building zones in the event of fire. The complex pressurization and code
requirements in healthcare construction can result in the need for hundreds of firesmoke dampers each costing $1500-$3000. Working closely with the architect, the
DBMC was able to reconfigure the layout of the distribution systems, reducing the
required fire-smoke dampers by 30%, resulting in a significant first cost savings in
addition to long term maintenance costs. This case study demonstrates the
competitive advantage of DBMC in design mechanical systems through an integrated
design and detailing process, and early consideration for constructability in design.
Principles of Lean and Green Mechanical Systems Design and Construction
The second phase of this research involved case studies and interviews of the
executive and operations level personnel of two design-build mechanical contractors.
The goal of these interviews was to identify areas of waste reduction and value added
processes that contributed to both first-cost savings and improved energy efficiency
of building projects. Interviews were conducted in the home office and fabrication
facilities of contractors, and focused on the design, documentation, and fabrication
processes that have the greatest influence the outcome of projects.
Interviews were used to assess design and construction services and processes
utilized by the companies. For each process, applications of lean principles which
produced green results were identified. The criteria for these applications were as
follows: (1) Lean processes – activities that: streamline construction process, improve
clarity of design, improve the integration of the mechanical design process with other
systems, reduce potential for error in design or construction, increase shop portion of
fabrication, and (2) Green results – savings in first costs, energy, water, or material
requirements of system, adds to flexibility of system, reduces long-term maintenance
costs, and the use of more environmentally friendly materials.
The results of these interviews in combination with the case study examples
are summarized in Tables 1 and 2. Three trends emerged as common themes: (1)
DBMC are often willing to adopt new technologies and innovative solutions due to
their understanding of the construction process and their willingness to be
accountable for the operation of these systems, (2) the integrated design and detailing
expertise possessed by DBMCs can result in the systems that are designed for both
efficient construction and operation, resulting in first cost savings and improved
operational efficiency, and (3) the early involvement of DBMC in the constructing
process allows more opportunities for innovative cost reducing ideas, such as the
elimination of fire-smoke dampers, and the adaptive re-use of existing systems to be
introduced and estimated.
Summary of Research Results
The goal of this research was to develop a descriptive model of key competencies and
competitive advantages possessed by design-build mechanical contractors can reduce
first costs through elimination of process waste, and at the same time contribute to the
goals of green projects. Tables 1 and 2 provide a summary of the results of both case
studies and interviews of design-build projects and organizations. Project activities
are identified with corresponding lean principles and green results identified for both
the design (Table 1) and construction (Table 2) phases of building projects.
The results summarized on Tables 1 and 2 provide a foundation to examine
how synergies between lean principles applied by construction organizations to
minimize cost and improve constructability of systems can contribute directly to the
pursuit of green goals on building projects. The tables also helps to illustrate the
broad benefits of design-build contracting strategies which fully enable the valueadded competencies of DBMCs to be employed on building projects for the mutual
benefit of both design, construction.
Conclusions
High Performance “green and “sustainable” building projects are continuing
to emerge as viable investments for facility owners. The competencies and
competitive advantages of design-build mechanical contractors offer significant
potential to improve traditional design-bid-build contracting approaches by reducing
first costs in combination with “right-sized” HVAC systems that are highly efficient
to operate.
Case studies of projects in which design-build mechanical services were
acquired to address unique and challenging project conditions provide examples of
how the combination of design and construction competencies were applied to
develop cost saving and energy efficient mechanical systems design solutions.
Examples of up to 20% initial costs savings combined with improved overall energy
efficiency in design were found on several case study projects.
Table 1: Design Principles of Lean and Green Mechanical Systems
Design-Build Process
Lean principle
Green result
Choose systems that minimize
cooling tower evaporative cycle
Use 2-pipe systems in lieu of 4pipe systems
Ensure sufficient space for
systems in plenums and shafts
Simplifies installation of HVAC
systems
Reduces installation time,
simplifies coordination
Simplifies coordination and
installation
Use high velocity air distribution
systems
locate equipment such that
connections are in straight lines
Design Documentation
Reduced ductwork size and
simplifies installation
Simplifies connections and hookups, maximizes prefabrication
Reduces water use of
Mech. system
Minimize piping and hanger
materials
Allows space for
commissioning,
maintenance; optimization
Minimizes duct and hanger
materials
Reduces fittings, materials,
and construction time
Include field expertise during
detailing
Allow engineering drawings to
double as shop drawings
Permits efficient layout of systems
and equipment
Reduces time to produce
drawings and reproduce shop
drawings, allows early
coordination of systems
Develop extensive flow diagrams
and system schematics showing
interface between systems
Clearly annotate mech./elec.
responsibilities on schematics and
wiring diagrams
Improves visibility of all systems
components, reduces errors and
missed items
Ensures clear scope of work for
mech. and elec. Contractors
Design Principles
Minimizes material waste
and simplifies construction
Saves time during design,
allows structural and Arch.
adjustments to be made
early, reduces change
orders
Reduces re-work, RFI, and
Change orders that affect
system performance
“Right sized” design; more
accurate bids, reduces RFI
and change orders
Equipment Selection
Couple smaller standard units in
lieu of larger custom units
Reduces lead time and improves
availability and reliability.
Utilize combined heat and power
strategies
Can improve efficiency and
reduce size of some systems
Improved operating
efficiency and reduced
maintenance
Flexible power
requirements, distributed /
energy production
Fitting Specification
Choose high quality fittings that
reduce field labor
Use “snap-fit” systems like
“ProPress” and “Victolic”
connections
Use “Flexible” connections at main
distribution and fixtures
Use ganged fixtures that can be
purchased or prefabricated
Minimize on-site labor and chance
for installation error
Minimize field labor, reduce field
defects in field construction,
reduced rework
Minimizes field fabrication and
labor
Minimize on-site labor and chance
for installation error
Reduces labor,
maintenance material costs
Saves initial labor cost and
maintenance costs
Reduces cost and material
waste
Reduces labor, material
and maintenance costs.
Table 2: Construction Principles of Lean and Green Mechanical Systems
Design-Build Process
Lean emphasis
Green results
Minimize elbows and complex
reductions
Use standard systems and
round/oval duct when possible
Wet-side fabrication
Simplifies fabrication and
installation
Simplifies fabrication and
installation
Saves fan energy
Minimize elbows and complex
reductions
Minimize field cutting and welds
Simplifies fabrication and
installation
Simplifies fabrication and
installation
Saves pump energy
Maximizes efficient factory labor
Less material waste,
saves time on site
Simplifies parts management and
material flow
Less wasted parts and
materials, reduced
maintenance, cost savings
Just-in-time fabrication and
delivery
Less damage and waste
of materials, reusable
packaging
Minimal disruption to work flow of
other trades
Productive and profitable
project for team members
Optimization of material use in
factory
Less wasted materials,
reduced material handling
costs.
Less wasted materials on
site, less packaging
materials on site
Less packaging materials
needed and related waste
Dry-side fabrication
Materials Management
Shop fabrication of ganged spools
and equipment racks
Purchasing
Use standard, proven, high quality
fixtures purchased in bulk
Deliveries to site
Alignment so design, fabrication,
and construction schedules match
On-Site Construction
Fast resolution of design and
construction conflicts
Waste Management
Waste minimization through
prefabrication
Increased prefabrication
Re-use of packaging materials
Commissioning
Complete commissioning over
project design, procurement,
construction, and building start-up
Reduces waste on site, and
related material handling,
movement
Reduces physical waste, better
production control
Commission as you go; identify
problems and defects close to
problem source
Reduces material waste
Reduces material waste,
fewer quality problems
Total commissioning
improves likelihood of
achieving expected
performance
The application of lean principles to identify waste reducing and value-added
activities in the conception, design, fabrication, construction of projects was
performed. Three trends emerged as common themes: (1) DBMC are often willing to
adopt new technologies and innovative solutions, (2) the integrated design and
detailing expertise possessed by DBMCs leads to both first cost and long term energy
cost savings, and (3) the value of early involvement of DBMC in the constructing
process to address challenging project conditions. An illustrative set of lean
principles and green results throughout these processes provides a compelling case
for the inclusion of design-build competencies on green building projects, and
provides a foundation upon which the development of “lean and green” project
delivery approaches can be defined.
ACKNOWLEDGMENTS
This research is sponsored by the Partnership for Achieving Construction Excellence
(PACE) at Penn State University: www.engr.psu/PACE.
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