Friday, September 24, 2010

Successful Cleanroom Design Strategies in Today’s LEED World



The design, engineering, and construction of high technology manufacturing space is technically unforgiving, requires significant financial investment, and demands careful attention to energy and natural resource usage. Coupled with a client’s desire to construct a LEED Gold certified 230,000 square foot (21,500 square meters) clean manufacturing plant, the stakes rise. This article will examine the process
GE Healthcare, its designers and construction team undertook to successfully take home the Gold, while reviewing some lessons learned. GE Healthcare, as a global leader in developing and manufacturing cutting edge medical diagnostic equipment that also delivers significant energy savings, was committed from the outset to building a more sustainable Digital X-ray clean manufacturing facility in North Greenbush, New York. GE is known globally for its ecomagination program, which the company characterizes as consistent with its mission to earn the best possible returns for shareowners by developing solutions that improve energy efficiency and reduce environmental impact. With strong leadership from GE, all team members were focused on sustainable design as a primary objective. An owner wholly committed to designing and obtaining LEED certification is a base requirement for project success.
From the beginning, the team concentrated on integrating cost effective, sustainable components that would carry through the architectural and engineering design phase and into the construction program, while providing functionality during the building’s occupancy phases. Operational needs and programming requirements were extensively assessed, with energy requirements defined for each space.
GE invested more than $130,000,000 (excluding production equipment) to build the facility. The cost of the sustainable and renewable energy features equaled $7.00 per square foot, or 1.6% more than conventional design. GE Healthcare anticipates the payback period for these sustainability costs to be 2.1 years.
The facility is designed to increase energy efficiency by 27% compared to a baseline building in minimal compliance with ASHRAE 90.1-2004. GE should realize combined energy savings of more than $750,000 annually. Projected annual electrical power savings of 8.6 million kWh and energy fossil savings of more than 6,800 MMBtu were realized as a result of the integrated engineering design. These annual power/electrical energy savings are equivalent to 800 homes and reduce greenhouse gas emissions equivalent to 448 automobiles.
The engineering and architectural design efforts could be summed up with the phrase, “Form follows function.” Cleanrooms add a level of complexity to the quest for a sustainable building. SMRT, architects, and engineers with more than two decades of clean manufacturing experience and a large number of LEED certified professionals in all disciplines, in collaboration with the H.L. Turner Group, Inc. and Hodess Construction Corporation, worked to meld the specialty engineering requirements of this high tech manufacturing facility with the latest, technically sound opportunities for energy conservation.
A charette workshop attended by key stakeholders kicked off the project. This workshop not only translated the philosophy of the client into actionable mandates but also helped establish realistic parameters for integrating sustainable components. William McDonough, a founding member of the US Green Building Council, a member of GE’s ecomagination Advisory Board and chairman of William McDonough + Partners, facilitated the charette. The owner, architect, engineers, and the entire consultant team worked together to transform GE Healthcare’s vision into the raw components of the building’s design, while organizing those components in a way that advanced the manufacturing work flow, efficiencies, and operational requirements. The workshop ensured that all stakeholders gained a common understanding of the project’s sustainable design goals, generated new ideas that contributed to the project’s success, and helped build a sense of ‘mission camaraderie’ at the beginning of a technically challenging project.
One result of the charette was the development of the “Main Street” concept accommodating major occupant circulation along a two-story light well/roof monitor, which provided refracted daylight into the interior office and circulation spaces. As a result, at least 92% of regularly occupied office spaces access natural daylight, and electrical demand is reduced.
From the beginning of the project, HL Turner and SMRT worked to evaluate costs, constructability, form, function, environmental advantage, and availability of material options. Utilizing energy modeling, energy options were evaluated, with close attention to operations and cost implications.
The building program broke out as follows:
Indoor Spaces:
  • Manufacturing: 34%
  • Mechanical/electrical: 45%
  • Conference rooms/main entrance lobby: 7%
  • Offices/laboratories: 11%
  • Shipping/receiving: 3%
Outdoor Spaces:
  • Undisturbed: 49.4%
  • Landscaping features/storm water management: 34.6%
  • Drives/roadway: 5.4%
  • Parking: 6.8%
  • Pedestrian walkway (some designed with lowreflective materials): 2.3%
  • Low reflective outdoor patio: 0.2%
The ability to work closely with local planning boards and other regulatory agencies to both meet regulatory requirements and ensure that functional needs and environmental considerations are addressed is important. The 230,000 square foot GE Healthcare facility operationally required less automobile parking than local ordinances mandated. The team negotiated reduced paved area by reserving green space for additional parking should demand expand.
The project team utilized an integrated engineering and design approach, incorporating active and passive sustainability strategies into the plan. Significant project challenges and building components include:
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BUILDING ENVELOPE
The team maximized the value of the building envelope with the following specifications:
  • Insulated, pre-cast and metal-framed walls boast an R-21 cavity and U-0.049 continuous value, versus code prescriptive R-13 cavity and U-0.123 continuous levels;
  • Metal joist/truss roof insulation provides R-54 insulation value versus code required R-24;
  • A high albedo TPO roof with an SRI value of 95 optimizes energy savings;
  • Slab perimeter insulation offers an R-8 or greater value; and
  • Use of high performance (double pane, tinted, low-E glass) windows boast solar heat gain coefficients and u-factors exceeding ASHRAE 90.1-2004.
Image 2
HVAC
The recirculating air system necessary to maintain manufacturing area cleanliness posed a unique challenge. The criterion: maintain ISO Class 5 (Class 100) for 365 days per year in the manufacturing areas with exposed product. The design basis was an airflow load of 55 cfm per square foot of floor area (the average office area is below 1 cfm per square foot). 100% of the 2' x 4' ceiling grid is fully populated with ULPA filters. The resulting 1,400,000 cfm of airflow consumes 660 kW of power, year-round.
Centralized re-circulation units with variable frequency drives (VFDs) and particle counter setback controls versus industry–standard constant-speed fan filter units provide automatically controlled airflow, based upon real-time measurement of unseen dust 0.3 microns or larger. Central fans are controlled automatically through a computerized Building Management System. The team projects the particle counting system will reduce airflow to an average of 45 cfm per square foot of floor area. This 18% reduction will result in a 45% reduction in fan energy demands.
GE Healthcare’s phased occupancy schedule created a challenge with air quality testing, underscoring the importance of coordinating an air quality testing plan as early as possible in the process.
Prior to occupancy, the project team wished to confirm that materials and indoor air quality best management practices had been implemented. A consultant was retained to conduct air quality testing. Scheduling was problematic—the owner had not planned on delaying occupancy of cleanroom spaces pending completion of the remaining building. Since support areas would still be under construction as manufacturing tools arrived, it made simultaneous testing throughout the building impossible. The solution: phased air quality testing, starting in the cleanrooms and later moving to other areas as construction allowed. This approach worked because different areas of the plant essentially represented separate buildings, with each area capable of individually meeting LEED requirements for air quality testing.
Premium efficiency motors with variable frequency drives were used for all systems including the variablespeed primary chilled water loop, the four process chilled water loops, the condenser water loop, the cooling tower fans, and the heating hot water loop.
A computer controlled central cooling system featuring a high efficiency variable-speed centrifugal chiller plant (0.539 kW/ton at ARI conditions and 0.340 kW/ton IPLV) instead of a code compliant centrifugal chiller plant (0.576 kW/ton) was specified.
The chilled water plant incorporates the “Hartman Loop” optimization control system. The control system optimizes all-variable speed plants by taking advantage of the exclusive characteristics of variable-speed pumps, chillers, and fans. With variable speed operation, the efficiency of each chiller compressor, pump, and fan increases as flow and load requirements fall. The plant sequences equipment to operate at between 30% and 50% of capacity when the plant is operating at partial load conditions. The operation of each chiller is coordinated with the other on-line chillers so that all chillers should operate at precisely the same speed. The coordination of condenser pump and tower fan speed is similar. As one variable is set (like chilled water flow), the others are varied in increments to minimize the kW of the entire plant, which is the ultimate goal.
When modeling the HVAC design and energy savings features, the design team faced two insurmountable challenges:
First, no methodology for modeling the “Hartman Loop” chilled water plant optimization control system existed. It is a very iterative process, and the accepted commercially available software is not yet able to model the systems as there are too many variables for current modeling software to handle.
Second, at the time of submission, there was no currently accepted supporting standard or other backup for substantiating a Cleanroom Airflow Reduction model for this type of bay-chase, large production cleanroom. The project submitted a model showing 27% cost savings, but was credited with only a 17.5% cost savings.
The design team intuitively knows the particle counting system and active ULPA-filtered recirculating airflow management will account for significant energy savings. With GEHC’s appropriate garment and cleaning protocols, the 100% ULPA ceiling coverage, and the design team’s cleanroom airflow experience, the systems are expected to maintain ISO Class 5 at airflows less than the ISO standards recommend.
The baseline was modeled at 55 cfm/sf airflow. It has been the design team’s experience that an airflow reduction to 45 cfm/sf will maintain ISO Class 5 and remove a significant amount of process equipment heat. However, since no study or standard exists to substantiate the airflow reduction assumptions, only a portion of the submitted points were awarded.
The clean-manufacturing industry continues to evolve. Like most industries, clean manufacturing is incorporating more environmentally conscious practices into their operations. The design team expects that cleanroom airflow reduction will be examined closely in the near future because it is “low hanging fruit.” The design team also anticipates the publication of formal studies providing direction to operators and designers.
Additional features include:
  • A 90% efficient hot water gas fired boiler plant;
  • Demand control ventilation for all office areas;
  • Non–ozone-depleting refrigerants;
  • Hydronic/radiant underslab heating; and
  • Enhanced commissioning of the HVAC system.
LIGHTING
Because approximately 92% of office space has access to natural light, lower building interior lighting power densities than maximums stipulated by code were used. Office and laboratory lighting is powered by a rooftop, 50KW photovoltaic system. Photosensitive and occupancy sensitive lighting controls provide lighting as needed.
LED site lighting uses 25% of the power required by a comparable standard site light.
Solar shading was integrated into the building design: west windows with two-story, vertical external solar shading and south windows using fixed exterior solar shades fastened to the window mullions.
Image 3
Solar arrays on the roof (Photo - Randall Perry)

WATER
Total water usage equals 116,000 gallons/year (439,000 liters/year). A variety of water conservation strategies were employed. The process water Reverse Osmosis (RO) system used in manufacturing, allows 17,600 gallons per day from RO system drains and filter backwashes to be piped to make-up water used for cooling tower and exhaust air scrubbers.
Water conservation fixtures were specified: the use of dual flush toilets, flush urinals, and faucet aerators save 47,000 gallons annually, or 29%, compared to a conventional office building.
Careful landscape design ensured that irrigation would not be required.

MATERIALS
Greater than 40% of the installed materials were recycled. The construction team made plans to install a high percentage of recycled content materials early in the project. This was accomplished by specifying recycled content percentages for target materials and highlighting this requirement in contract documents. Four materials were 100% recycled: the pre-stressed strand found in the pre-cast wall panels, the aluminum-raised access flooring in the Class 100 cleanrooms, MDF, and particleboard. The steel joists, 85.5% recycled, had the highest recycled value of $1,561,274.
Forest Stewardship Council (FSC)-certified wood and low volatile organic compound (VOC) paints, stains, carpets, glued wood products, sealants, and adhesives were chosen wherever possible. The interiors team also specified low-emitting “Green Guard” or SCS Indoor Advantage certified furniture.
More than 56% of wood installed on the job was FSC certified. FSC certified wood required a longer lead time, and although this didn’t create any problems, it could have a significant impact on projects where FSC certified wood is not specified far enough in advance.
When utilizing multiple subcontractors during construction, design and construction teams need to be diligent in their efforts to prevent the installation of non-compliant materials throughout the course of the job, particularly adhesives and sealants which are more difficult to monitor.
CONSTRUCTION
The client selected an “open book” construction management (CM) arrangement, led by Turner Construction Company. The CM scheduled the project, managed the early procurement of long-lead items, and obtained multiple bids for all bid packages. They worked closely with GEHC and the design team to pre-select qualified contractors and evaluate bids.
Groundbreaking took place in the fall of 2007. The construction phase ran through April 2009, when ramping operations accelerated. Ensuring LEED compliance during the construction phase is a critical success factor during a risky phase. A high number of specialty subcontractors were required, making the communications of both the spirit and specific knowledge of LEED program goals and compliance requirements paramount. The core team continuously reinforced this emphasis with all members of the onsite construction team.
Some of the core practices that drove success during the construction phase included:
  • Clear expectations and performance requirements, were developed and continuously communicated to all members of the construction team, including subcontractors;
  • All members of the construction team received onsite training, specific performance requirements and regular compliance reviews throughout construction;
  • Contractual mechanisms were used to ensure subcontractor compliance;
  • A LEED credit tracking spreadsheet used to clarify responsibilities and technical considerations, as well as to estimate costs, was developed and made accessible to all team members;
  • Materials usage and record keeping of all construction team members was continuously tracked, while building materials were reviewed to ensure local, recycled, and certified content in compliance with LEED guidelines;
  • A comprehensive waste recycling management plan was developed prior to construction start. Diverting 75% of waste from landfills proved to be one of the major management challenges during the construction phase. Recycling during construction was more management intensive than other LEED credits.
  • Separate dumpsters to collect cardboard, wood, metal, sheet rock, and masonry materials were placed on site and subcontractors were required to utilize these dumpsters by contractual agreement. Any dumpsters assigned as a collection vessel for recyclables but contaminated by dissimilar materials were unloaded and re-sorted accordingly. Even with contractual agreements and weekly reminders about recycling, it was still challenging to divert 75% of waste. Out of habit, workers tended to dispose of waste in any available dumpster. Constantly monitoring this situation and driving the required behavioral changes was time consuming. Reflecting on the project, the team decided that co-mingled recycling would be worth the additional expense, by providing greater assurance of reaching a set goal and reducing the amount of required management time;
  • The CM worked diligently to ensure that LEED documentation was completed by all parties in a timely and accurate manner; and
  • The value of building commissioning was recognized and integrated into the project. Third-party enhanced commissioning and FDA-required validation were undertaken to ensure operational efficiencies were functioning as designed and engineered.
Image 5

ENERGY USE SUMMARY
Energy use information is still incomplete as operations ramp up. Production equipment (or “tools”) represents a significant portion of the HVAC cooling load, from sensible heat gain to make-up air conditioning.
The integrated Building Management System allows the owner to measure chilled water, heating, hot water, and electrical power use. These metrics will be used to track overall energy consumption and in the Hartman Loop chilled water plant optimization algorithms.
The Energy Model offers a much more comprehensive summary, accounting for full build-out with all tools installed. Below is the projected building energy usage, based on the energy model.
The engineering and construction demands to meld clean manufacturing with aspirational sustainability goals require vision, a committed owner, close teamwork, and an experienced and technically capable design and construction team with an unfaltering eye to both anticipate and monitor details throughout the process. The team members agree that the payback— environmentally, professionally, and financially—is well worth the effort.
Useful Information Resources and Software:
  • Equest, using DOE-2.2-44d3
  • LEED for New Construction, version 2.2, Reference Guide
  • LEED Energy Modeling Protocol (EMP)
  • ASHRAE Standards 90.1, 62.1, and 52.2 and their user guides
  • SMACNA Guidelines for Indoor Environmental Quality During Construction

3 comments:

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Spectro Labs Limited, Delhi, India said...

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