Arlon Upgrades Cleanrooms at its Californian Facility

Arlon Electronic Materials (a division of Rogers Corporation), a US manufacturer of specialty high performance materials used in the defense, space and avionics industries, has made significant capital investment in upgrading cleanroom facilities at its site in Rancho Cucamonga, CA, US.

The company has installed new equipment in its build-up and sheeting processes to reduce foreign object debris (FOD) and enhance cleanliness of the manufacturing process of all of its prepreg and laminate materials. Arlon said it is moving forward with plans to expand the use of cleanroom technology into other processes throughout its operation for the rest of this year and next. Key improvements include enclosing prepreg sheeting and build-up areas using modular technology, resulting in dramatically smaller spaces to keep free of particle contaminants.

The overall footprint of the build-up area has been reduced by more than 50%, enhancing environmental control and particle reduction. The improved cleanrooms with substantially reduced particle counts are rated ISO Class 7 (Class 10,000). A new air filtration system results in 50 to 60 volumetric air exchanges every hour and creates positive pressure within the room. This ensures the constant filtration and introduction of cleaner air, which aids in the removal of any residual particulates. Particle count data indicates a 70% reduction in airborne particles during the build-up process since the installation of the various cleanroom technologies. The company has always used HEPA-filtered air and daily room cleaning protocols to keep particulates to a minimum. The implementation of new cleanroom equipment and controlled air flow has allowed operational cleanliness to reach a higher standard.

Space Station Processing Facility Update

One of the most recent research labs was built as part of the Space Station Processing Facility (SSPF) at Kennedy Space Center (KSC) in 2014. This science lab was built to conduct experiments on various species to understand their performance both on Earth and in Space under different environmental conditions.

Despite many constraints, they plan to demonstrate how a highly energy efficient facility achieved LEED Silver certification. The challenges of this project are due to some of the following requirements:

The project site was located on a previously developed land.
The site location limited the building footprint by the adjacent access roads and other existing buildings.
New facility had to be located adjacent to one of the most secure facilities with high value payloads and national assets.
Utilities had to be brought from adjacent facilities whose operation could not be disturbed.
Limited time for construction due to proposed launch schedules stringent facility environmental requirements (for example, shall maintain 40 to 65% humidity controllable in 1% increments).
Facility should be LEED certified with energy efficient systems.
Design-build process shall meet the limited budget.
All products had to comply with Buy American Act.
Control system needed to be highly flexible and had to control the fully redundant mechanical systems.
Control system needed to interact with central control system for the entire KSC.
The facilities and operation had to be AAALAC certified.

Background

Building a standalone vivarium which maintains pressure relationships between various communicating spaces and that maintains positive pressure with respect to exterior environment is a huge challenge. The exterior walls had to be designed as breathable and as well as cleanable for the level of cleanliness required in a hot and humid climate. The following wall detail was used to build the lab envelope so that above goals could be achieved. Exterior water proofing had water vapor permeance less than 1 perm and interior water based epoxy coating had approximately 5 perms.

Typically, there are options for orienting a building and the selecting the most optimum building orientation for the least amount of energy use. However, this site was selected based on adjacency, security, and available utility constraints. Therefore, developing a building footprint and floor plan that meets the functional requirements of a demanding lab with all the functionalities included was a huge challenge. Several design meetings were conducted to finalize, select the most optimum acceptable layout by the users and facility maintenance personnel and to meet life safety regulations.

Besides the normal structural goals for ordinary structure, there were additional challenges for this facility. To provide the optimum facility within budget and schedule, both engineers and architects held several meetings with the various construction trades to select the most durable and available construction materials for the new Science Annex. The following paragraphs summarize some of the challenges and how they were overcome.

To be sustainable and green, this project opted to use materials that have high recycling contents such as concrete masonry units (CMU), concrete with slag and fly ash, structural steel, steel joists, and steel deck. The use of these materials helped capture some LEED points.

To control humidity precisely, chilled water option was selected for this small building by the mechanical design team. Routing chilled water supply and return from the adjacent SSPF mechanical room (approximately 200 ft. away with 80 ft. in change in elevation) to the Science Annex was challenging. The selected option was to route the pipes up to the SSPF roof, continue to run the pipes on supports over the SSPF High Bay (contains space station modules and other flight hardware), and then run the pipes down along the side of the 80 ft. high building to the AHUs located on the ground adjacent to the Science Annex. The challenge was to maintain water tight roof over the expensive flight hardware for a roof that is 20 years old. Then, select suitable structural members to support the curbs that carry the chilled water pipes. The pipe roof penetration curb and gooseneck was custom designed. The pipe supports were designed using finite element model to determine precisely the pipe deflections and reactions on the roof structure.

To meet the stringent wind pressures on the walls and roof of the Science Annex, reinforced CMU load bearing walls and steel deck for the roof were selected. Steel deck was modeled structurally as diaphragm system to resist lateral wind loads.

Since the facility footprint was very limited, it became clear as the design developed that more space was required to house mechanical equipment. To meet this demand, a mezzanine within the mechanical room was added during the design-build process. The design was challenging as the vertical clear space in the mechanical room was already established. Shallow roof framing members were utilized to maximize the head room above the mezzanine.

To meet the budget, only 8-in CMU block could be used for the exterior walls. To keep the 8-in CMU and deal with the 157 MPH wind speeds at the site location, and wall heights, the design engineers integrated the wall into the floor slab. This created a two span condition versus one simple span. By doing so, the use of reinforced 8-in CMU was made possible.

Mechanical Systems Challenges

The prime goals of this facility design included:

Maintain required air changes (15 ACH at minimum for several spaces) and adjust as needed based on facility occupancy
Maintain positive and negative pressures in various interconnected spaces at all times based on the type of space use
Design a couple of spaces with both +ve and –ve pressure option with respect to corridors with switching capabilities through control system when needed
Maintain space temperature from 65 to 78 F (adjustable in 0.5 F interval)
Maintain RH in critical rooms from 40 to 60% adjustable in one percent increments throughout the year
Maintain overall building pressure to be positive to ensure humidity control under all conditions
Provide highly energy-efficient systems meeting the above goals using once through air conditioning system.

To meet the above challenges, a variable speed direct expansion (DX) type AC system was initially selected. However, through the energy analysis exercise it was realized that getting enough LEED credits and control of precise humidity would be very difficult with this approach even though it is possible.

Therefore, we explored options to bring chilled water from a central water-cooled chiller plant located approximately 1,200 ft. away from the building. We had to incorporate a circulation pump to the existing primary/ secondary loop to achieve this. This option was achieved with no additional costs to the customer.

The air-handling unit was designed as a once through system to maintain the highest level of cleanliness specified. Filtration was achieved with UV lights and HEPA filters. All the mechanical and control systems were designed with 100% redundancy. Due to the fact that animals are very sensitive to the rate of change in temperature, we included electric heat for the terminal heats with SCR control instead of steam heat even though enough steam was available in the facility. Steam heat is more effective and would change the room temperature at a much faster rate than desired.

The steam boilers were designed to handle both autoclave and cage washer steam loads with condensate recovery without any pumps. Natural gas service was extended to this facility for steam boiler and water heaters. Water heaters were designed for 180 F high temperature hot water supply to minimize the steam use in cage washer and maximize energy savings.

The humidifier system uses RO/DI water so that cleanliness can be maintained. In addition, the DI water is used for animals’ consumption. Packaged DI water system was selected with a 500 gallon storage tank. Compressed air was extended from adjacent main building using one of the branch connections available and adding another isolation valve for future without disturbing existing operations.

The entire control system sequence of operations and failure analysis was developed based on different operating scenarios at this lab and possible impacts due to either equipment or a control device failure. Alternate means of control without losing temperature, humidity, and pressure relationships were identified. Switch over of major equipment was tested to ensure that facility conditions can be restored within three minutes in case of a major equipment failure such as an air handler or exhaust fan.

The project required receptacles every 4 ft. in each of the rooms. The required number of circuits created extensive conduit planning to coordinate with other disciplines. They had to relocate some of the existing feeds to other buildings to make room for feeds to this building.

LEED Certification

The SSPF Science Annex laboratory had to be LEED silver certified per NASA mandates for all new buildings. It was a very challenging endeavor as this is a lab building with once through air conditioning system with prescribed air changes per hour requirements. The lab operation is typically dictated by mission requirements. Therefore, the available flexibility in operation (based on whether the lab is in operation before the mission or in use aft.er the mission) was thoroughly modeled/controls programmed to save as much energy as possible without losing cleanliness requirements.

Figure 2 shows the various LEED points obtained for LEED silver certification. This building is designed with no windows for lighting control of various experiments. The roof was insulated with R-30 and walls were insulated with R-14 to minimize heat loads of perimeter spaces. Supply air temperature reset was incorporated to minimize reheat. Highest possible efficiency water heaters and steam boilers were used in this project. Several recycled materials were used to be environmentally friendly. The building operations were thoroughly reviewed for AAALAC certification.

Conclusion

In summary, the Science Annex design-build process was a huge success due to extensive planning, by modeling the building systems thoroughly and updating during construction phase, the ability to work with the selected group of contractors who got involved right from the design phase, an understanding the limitations from the existing utility services, extensive knowledge of the system and support from the customer side, and the fact that a design professional was involved from concepts to commissioning phase to make various critical decisions.

In conclusion, the integrated design-build delivery process is successful for highly complex projects with the right team of engineers, architects, and contractors with customer involvement throughout the process.

Acknowledgements:

NASA KSC Team, CDE Design and Construction Team
DJ Design Architects, Daytona, FL, Doug Wilson General Contractors, Cape Canaveral, FL
ALC Controls, Orlando, FL, Enthalpy ENC Mechanical Contractors, Orlando, FL

Kannan Rengarajan, P.E., is one of the founders of CDE serves as the Lead Mechanical Engineer. He holds a Masters degree in Mechanical Engineering. He has over 32 years of multi-disciplinary engineering projects experience and has authored several articles in the HVAC field for hot and humid climates. www.cdeco.com

Luft.i Mized, P.E., is one of the founders of CDE serves as the Lead Structural Engineer. He holds a Masters degree in Structural Engineering. Mr. Mized has over 32 years of multi-disciplinary engineering projects experience and was nominated as the “Engineer of the Year” by Canaveral Council of Technical Societies/NSPE. www.cdeco.com

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